--- loncom/interface/lonnavmaps.pm	2002/09/26 16:56:21	1.55
+++ loncom/interface/lonnavmaps.pm	2003/09/30 15:37:18	1.236
@@ -1,7 +1,7 @@
 # The LearningOnline Network with CAPA
 # Navigate Maps Handler
 #
-# $Id: lonnavmaps.pm,v 1.55 2002/09/26 16:56:21 bowersj2 Exp $
+# $Id: lonnavmaps.pm,v 1.236 2003/09/30 15:37:18 bowersj2 Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -36,1071 +36,1655 @@
 # 3/1/1,6/1,17/1,29/1,30/1,2/8,9/21,9/24,9/25 Gerd Kortemeyer
 # YEAR=2002
 # 1/1 Gerd Kortemeyer
-#
+# Oct-Nov Jeremy Bowers
+# YEAR=2003
+# Jeremy Bowers ... lots of days
 
 package Apache::lonnavmaps;
 
 use strict;
 use Apache::Constants qw(:common :http);
-use Apache::lonnet();
 use Apache::loncommon();
-use HTML::TokeParser;
-use GDBM_File;
-
-# -------------------------------------------------------------- Module Globals
-my %hash;
-my @rows;
+use Apache::lonmenu();
+use Apache::lonlocal;
+use POSIX qw (floor strftime);
+use Data::Dumper; # for debugging, not always used
+
+# symbolic constants
+sub SYMB { return 1; }
+sub URL { return 2; }
+sub NOTHING { return 3; }
+
+# Some data
+
+my $resObj = "Apache::lonnavmaps::resource";
+
+# Keep these mappings in sync with lonquickgrades, which uses the colors
+# instead of the icons.
+my %statusIconMap = 
+    (
+     $resObj->CLOSED       => '',
+     $resObj->OPEN         => 'navmap.open.gif',
+     $resObj->CORRECT      => 'navmap.correct.gif',
+     $resObj->INCORRECT    => 'navmap.wrong.gif',
+     $resObj->ATTEMPTED    => 'navmap.ellipsis.gif',
+     $resObj->ERROR        => ''
+     );
+
+my %iconAltTags = 
+    ( 'navmap.correct.gif' => 'Correct',
+      'navmap.wrong.gif'   => 'Incorrect',
+      'navmap.open.gif'    => 'Open' );
+
+# Defines a status->color mapping, null string means don't color
+my %colormap = 
+    ( $resObj->NETWORK_FAILURE        => '',
+      $resObj->CORRECT                => '',
+      $resObj->EXCUSED                => '#3333FF',
+      $resObj->PAST_DUE_ANSWER_LATER  => '',
+      $resObj->PAST_DUE_NO_ANSWER     => '',
+      $resObj->ANSWER_OPEN            => '#006600',
+      $resObj->OPEN_LATER             => '',
+      $resObj->TRIES_LEFT             => '',
+      $resObj->INCORRECT              => '',
+      $resObj->OPEN                   => '',
+      $resObj->NOTHING_SET            => '',
+      $resObj->ATTEMPTED              => '',
+      $resObj->ANSWER_SUBMITTED       => ''
+      );
+# And a special case in the nav map; what to do when the assignment
+# is not yet done and due in less then 24 hours
+my $hurryUpColor = "#FF0000";
 
-#
-# These cache hashes need to be independent of user, resource and course
-# (user and course can/should be in the keys)
-#
+sub handler {
+    my $r = shift;
+    real_handler($r);
+}
 
-my %courserdatas;
-my %userrdatas;
+sub real_handler {
+    my $r = shift;
 
-#
-# These global hashes are dependent on user, course and resource, 
-# and need to be initialized every time when a sheet is calculated
-#
-my %courseopt;
-my %useropt;
-my %parmhash;
+    # Handle header-only request
+    if ($r->header_only) {
+        if ($ENV{'browser.mathml'}) {
+            &Apache::loncommon::content_type($r,'text/xml');
+        } else {
+            &Apache::loncommon::content_type($r,'text/html');
+        }
+        $r->send_http_header;
+        return OK;
+    }
 
-# This parameter keeps track of whether obtaining the user's information
-# failed, which the colorizer in astatus can use
-my $networkFailedFlag = 0;
+    # Send header, don't cache this page
+    if ($ENV{'browser.mathml'}) {
+        &Apache::loncommon::content_type($r,'text/xml');
+    } else {
+        &Apache::loncommon::content_type($r,'text/html');
+    }
+    &Apache::loncommon::no_cache($r);
+    $r->send_http_header;
 
-# ------------------------------------------------------------------ Euclid gcd
+    # Create the nav map
+    my $navmap = Apache::lonnavmaps::navmap->new();
 
-sub euclid {
-    my ($e,$f)=@_;
-    my $a; my $b; my $r;
-    if ($e>$f) { $b=$e; $r=$f; } else { $r=$e; $b=$f; }
-    while ($r!=0) {
-        $a=$b; $b=$r;
-        $r=$a%$b;
+    if (!defined($navmap)) {
+        my $requrl = $r->uri;
+        $ENV{'user.error.msg'} = "$requrl:bre:0:0:Course not initialized";
+        return HTTP_NOT_ACCEPTABLE;
     }
-    return $b;
-}
 
-# --------------------------------------------------------------------- Parmval
-
-# -------------------------------------------- Figure out a cascading parameter
-#
-# For this function to work
-#
-# * parmhash needs to be tied
-# * courseopt and useropt need to be initialized for this user and course
-#
+    $r->print("<html><head>\n");
+    $r->print("<title>".&mt('Navigate Course Contents')."</title>");
+# ------------------------------------------------------------ Get query string
+    &Apache::loncommon::get_unprocessed_cgi($ENV{'QUERY_STRING'},['register']);
+    
+# ----------------------------------------------------- Force menu registration
+    my $addentries='';
+    if ($ENV{'form.register'}) {
+       $addentries=' onLoad="'.&Apache::lonmenu::loadevents().
+	   '" onUnload="'.&Apache::lonmenu::unloadevents().'"';
+       $r->print(&Apache::lonmenu::registerurl(1));
+    }
 
-sub parmval {
-    my ($what,$symb)=@_;
-    my $cid=$ENV{'request.course.id'};
-    my $csec=$ENV{'request.course.sec'};
-    my $uname=$ENV{'user.name'};
-    my $udom=$ENV{'user.domain'};
+    # Header
+    $r->print('</head>'.
+              &Apache::loncommon::bodytag('Navigate Course Contents','',
+                                    $addentries,'','',$ENV{'form.register'}));
+    $r->print('<script>window.focus();</script>');
 
-    unless ($symb) { return ''; }
-    my $result='';
+    $r->rflush();
 
-    my ($mapname,$id,$fn)=split(/\_\_\_/,$symb);
+    # Check that it's defined
+    if (!($navmap->courseMapDefined())) {
+        $r->print('<font size="+2" color="red">Coursemap undefined.</font>' .
+                  '</body></html>');
+        return OK;
+    }
 
-# ----------------------------------------------------- Cascading lookup scheme
-    my $rwhat=$what;
-    $what=~s/^parameter\_//;
-    $what=~s/\_/\./;
+    # See if there's only one map in the top-level, if we don't
+    # already have a filter... if so, automatically display it
+    # (older code; should use retrieveResources)
+    if ($ENV{QUERY_STRING} !~ /filter/) {
+        my $iterator = $navmap->getIterator(undef, undef, undef, 0);
+        my $curRes;
+        my $sequenceCount = 0;
+        my $sequenceId;
+        while ($curRes = $iterator->next()) {
+            if (ref($curRes) && $curRes->is_sequence()) {
+                $sequenceCount++;
+                $sequenceId = $curRes->map_pc();
+            }
+        }
+        
+        if ($sequenceCount == 1) {
+            # The automatic iterator creation in the render call 
+            # will pick this up. We know the condition because
+            # the defined($ENV{'form.filter'}) also ensures this
+            # is a fresh call.
+            $ENV{'form.filter'} = "$sequenceId";
+        }
+    }
 
-    my $symbparm=$symb.'.'.$what;
-    my $mapparm=$mapname.'___(all).'.$what;
-    my $usercourseprefix=$uname.'_'.$udom.'_'.$cid;
+    my $jumpToFirstHomework = 0;
+    # Check to see if the student is jumping to next open, do-able problem
+    if ($ENV{QUERY_STRING} eq 'jumpToFirstHomework') {
+        $jumpToFirstHomework = 1;
+        # Find the next homework problem that they can do.
+        my $iterator = $navmap->getIterator(undef, undef, undef, 1);
+        my $curRes;
+        my $foundDoableProblem = 0;
+        my $problemRes;
+        
+        while (($curRes = $iterator->next()) && !$foundDoableProblem) {
+            if (ref($curRes) && $curRes->is_problem()) {
+                my $status = $curRes->status();
+                if ($curRes->completable()) {
+                    $problemRes = $curRes;
+                    $foundDoableProblem = 1;
+
+                    # Pop open all previous maps
+                    my $stack = $iterator->getStack();
+                    pop @$stack; # last resource in the stack is the problem
+                                 # itself, which we don't need in the map stack
+                    my @mapPcs = map {$_->map_pc()} @$stack;
+                    $ENV{'form.filter'} = join(',', @mapPcs);
 
-    my $seclevel= $usercourseprefix.'.['.$csec.'].'.$what;
-    my $seclevelr=$usercourseprefix.'.['.$csec.'].'.$symbparm;
-    my $seclevelm=$usercourseprefix.'.['.$csec.'].'.$mapparm;
+                    # Mark as both "here" and "jump"
+                    $ENV{'form.postsymb'} = $curRes->symb();
+                }
+            }
+        }
 
-    my $courselevel= $usercourseprefix.'.'.$what;
-    my $courselevelr=$usercourseprefix.'.'.$symbparm;
-    my $courselevelm=$usercourseprefix.'.'.$mapparm;
+        # If we found no problems, print a note to that effect.
+        if (!$foundDoableProblem) {
+            $r->print("<font size='+2'>All homework assignments have been completed.</font><br /><br />");
+        }
+    } else {
+        $r->print("<a href='navmaps?jumpToFirstHomework'>" .
+       &mt("Go To My First Homework Problem")."</a>&nbsp;&nbsp;&nbsp;&nbsp;");
+    }
 
-# ---------------------------------------------------------- first, check user
-    if ($uname) {
-        if ($useropt{$courselevelr}) { return $useropt{$courselevelr}; }
-        if ($useropt{$courselevelm}) { return $useropt{$courselevelm}; }
-        if ($useropt{$courselevel}) { return $useropt{$courselevel}; }
+    my $suppressEmptySequences = 0;
+    my $filterFunc = undef;
+    my $resource_no_folder_link = 0;
+
+    # Display only due homework.
+    my $showOnlyHomework = 0;
+    if ($ENV{QUERY_STRING} eq 'showOnlyHomework') {
+        $showOnlyHomework = 1;
+        $suppressEmptySequences = 1;
+        $filterFunc = sub { my $res = shift; 
+                            return $res->completable() || $res->is_map();
+                        };
+        $r->print("<p><font size='+2'>".&mt("Uncompleted Homework")."</font></p>");
+        $ENV{'form.filter'} = '';
+        $ENV{'form.condition'} = 1;
+	$resource_no_folder_link = 1;
+    } else {
+        $r->print("<a href='navmaps?showOnlyHomework'>" .
+       &mt("Show Only Uncompleted Homework")."</a>&nbsp;&nbsp;&nbsp;&nbsp;");
     }
 
-# ------------------------------------------------------- second, check course
-    if ($csec) {
-        if ($courseopt{$seclevelr}) { return $courseopt{$seclevelr}; }
-        if ($courseopt{$seclevelm}) { return $courseopt{$seclevelm}; }
-        if ($courseopt{$seclevel}) { return $courseopt{$seclevel}; }
+    # renderer call
+    my $renderArgs = { 'cols' => [0,1,2,3],
+                       'url' => '/adm/navmaps',
+                       'navmap' => $navmap,
+                       'suppressNavmap' => 1,
+                       'suppressEmptySequences' => $suppressEmptySequences,
+                       'filterFunc' => $filterFunc,
+		       'resource_no_folder_link' => $resource_no_folder_link,
+                       'r' => $r};
+    my $render = render($renderArgs);
+    $navmap->untieHashes();
+
+    # If no resources were printed, print a reassuring message so the
+    # user knows there was no error.
+    if ($renderArgs->{'counter'} == 0) {
+        if ($showOnlyHomework) {
+            $r->print("<p><font size='+1'>".&mt("All homework is currently completed").".</font></p>");
+        } else { # both jumpToFirstHomework and normal use the same: course must be empty
+            $r->print("<p><font size='+1'>This course is empty.</font></p>");
+        }
     }
 
-    if ($courseopt{$courselevelr}) { return $courseopt{$courselevelr}; }
-    if ($courseopt{$courselevelm}) { return $courseopt{$courselevelm}; }
-    if ($courseopt{$courselevel}) { return $courseopt{$courselevel}; }
+    $r->print("</body></html>");
+    $r->rflush();
 
-# ----------------------------------------------------- third, check map parms
+    return OK;
+}
 
-    my $thisparm=$parmhash{$symbparm};
-    if ($thisparm) { return $thisparm; }
+# Convenience functions: Returns a string that adds or subtracts
+# the second argument from the first hash, appropriate for the 
+# query string that determines which folders to recurse on
+sub addToFilter {
+    my $hashIn = shift;
+    my $addition = shift;
+    my %hash = %$hashIn;
+    $hash{$addition} = 1;
 
-# ----------------------------------------------------- fourth , check default
+    return join (",", keys(%hash));
+}
 
-    my $default=&Apache::lonnet::metadata($fn,$rwhat.'.default');
-    if ($default) { return $default}
+sub removeFromFilter {
+    my $hashIn = shift;
+    my $subtraction = shift;
+    my %hash = %$hashIn;
 
-# --------------------------------------------------- fifth , cascade up parts
+    delete $hash{$subtraction};
+    return join(",", keys(%hash));
+}
 
-    my ($space,@qualifier)=split(/\./,$rwhat);
-    my $qualifier=join('.',@qualifier);
-    unless ($space eq '0') {
-        my ($part,$id)=split(/\_/,$space);
-        if ($id) {
-            my $partgeneral=&parmval($part.".$qualifier",$symb);
-            if ($partgeneral) { return $partgeneral; }
-        } else {
-            my $resourcegeneral=&parmval("0.$qualifier",$symb);
-            if ($resourcegeneral) { return $resourcegeneral; }
+# Convenience function: Given a stack returned from getStack on the iterator,
+# return the correct src() value.
+# Later, this should add an anchor when we start putting anchors in pages.
+sub getLinkForResource {
+    my $stack = shift;
+    my $res;
+
+    # Check to see if there are any pages in the stack
+    foreach $res (@$stack) {
+        if (defined($res) && $res->is_page()) {
+            return $res->src();
         }
     }
-    return '';
+
+    # Failing that, return the src of the last resource that is defined
+    # (when we first recurse on a map, it puts an undefined resource
+    # on the bottom because $self->{HERE} isn't defined yet, and we
+    # want the src for the map anyhow)
+    foreach (@$stack) {
+        if (defined($_)) { $res = $_; }
+    }
+
+    return $res->src();
 }
 
+# Convenience function: This seperates the logic of how to create
+# the problem text strings ("Due: DATE", "Open: DATE", "Not yet assigned",
+# etc.) into a seperate function. It takes a resource object as the
+# first parameter, and the part number of the resource as the second.
+# It's basically a big switch statement on the status of the resource.
 
+sub getDescription {
+    my $res = shift;
+    my $part = shift;
+    my $status = $res->status($part);
 
-# ------------------------------------------------------------- Find out status
-# return codes
-# tcode (timecode)
-# 1: will open later
-# 2: is open and not past due yet
-# 3: is past due date
-# 4: due in the next 24 hours
-#
-# code (curent solved status)
-# 1: not attempted
-# 2: attempted but wrong, or incorrect by instructor
-# 3: solved or correct by instructor
-# 4: partially correct (one or more parts correct)
-# "excused" needs to be supported, but is not yet.
-sub astatus {
-    my $rid=shift;
-    my $code=0;
-    my $ctext='';
-    $rid=~/(\d+)\.(\d+)/;
-    my $symb=&Apache::lonnet::declutter($hash{'map_id_'.$1}).'___'.$2.'___'.
-        &Apache::lonnet::declutter($hash{'src_'.$rid});
-    my %duedate=();
-    my %opendate=();
-    my %answerdate=();
-    # need to always check part 0's open/due/answer status
-    foreach (sort(split(/\,/,&Apache::lonnet::metadata($hash{'src_'.$rid},'allpo\ssiblekeys')))) {
-        if ($_=~/^parameter\_(.*)\_opendate$/) {
-            my $part=$1;
-            $duedate{$part}=&parmval($part.'.duedate',$symb);
-            $opendate{$part}=&parmval($part.'.opendate',$symb);
-            $answerdate{$part}=&parmval($part.'.answerdate',$symb);
-            if (&parmval($part.'.opendate.type',$symb) eq 'date_interval') {
-                $opendate{$part}=$duedate{$part}-$opendate{$part};
-            }
-            if (&parmval($part.'.answerdate.type',$symb) eq 'date_interval') {
-                $answerdate{$part}=$duedate{$part}+$answerdate{$part};
-            }
+    if ($status == $res->NETWORK_FAILURE) { 
+        return &mt("Having technical difficulties; please check status later"); 
+    }
+    if ($status == $res->NOTHING_SET) {
+        return &mt("Not currently assigned.");
+    }
+    if ($status == $res->OPEN_LATER) {
+        return "Open " . timeToHumanString($res->opendate($part));
+    }
+    if ($status == $res->OPEN) {
+        if ($res->duedate($part)) {
+            return &mt("Due")."  " .timeToHumanString($res->duedate($part));
+        } else {
+            return &mt("Open, no due date");
         }
     }
-    my $now=time;
-    my $tcode=0;
-
-    my %returnhash=&Apache::lonnet::restore($symb);
-
-    foreach (sort(keys(%opendate))) {
-        my $duedate=$duedate{$_};
-        my $opendate=$opendate{$_};
-        my $answerdate=$answerdate{$_};
-        my $preface='';
-        unless ($_ eq '0') { $preface=' Part: '.$_.' '; }
-        if ($opendate) {
-            if ($now<$duedate || (!$duedate)) {
-                unless ($tcode==4) { $tcode=2; }
-                if ($duedate) {
-                    $ctext.=$preface.'Due: '.localtime($duedate);
-                } else {
-                    $ctext.=$preface.'No Due Date';
-                }
-                if ($now<$opendate) {
-                    unless ($tcode) { $tcode=1; }
-                    $ctext.=$preface.'Open: '.localtime($opendate);
-                }
-                if ($duedate && $duedate-$now<86400) {
-                    $tcode=4;
-                    $ctext.=$preface.'Due: '.localtime($duedate);
-                }
-            } else {
-                unless (($tcode==4) || ($tcode eq 2)) { $tcode=3; }
-                if ($now<$answerdate) {
-                    $ctext.='Answer: '.localtime($duedate);
-                }
+    if ($status == $res->PAST_DUE_ANSWER_LATER) {
+        return &mt("Answer open")." " . timeToHumanString($res->answerdate($part));
+    }
+    if ($status == $res->PAST_DUE_NO_ANSWER) {
+        return &mt("Was due")." " . timeToHumanString($res->duedate($part));
+    }
+    if ($status == $res->ANSWER_OPEN) {
+        return &mt("Answer available");
+    }
+    if ($status == $res->EXCUSED) {
+        return &mt("Excused by instructor");
+    }
+    if ($status == $res->ATTEMPTED) {
+        return &mt("Answer submitted, not yet graded");
+    }
+    if ($status == $res->TRIES_LEFT) {
+        my $tries = $res->tries($part);
+        my $maxtries = $res->maxtries($part);
+        my $triesString = "";
+        if ($tries && $maxtries) {
+            $triesString = "<font size=\"-1\"><i>($tries of $maxtries tries used)</i></font>";
+            if ($maxtries > 1 && $maxtries - $tries == 1) {
+                $triesString = "<b>$triesString</b>";
             }
-        } else {
-            unless (($tcode==2) || ($tcode==4)) { $tcode=1; }
         }
-        
-        my $status=$returnhash{'resource.'.$_.'.solved'};
-        
-        if ($status eq 'correct_by_student') {
-            if ($code==0||$code==3) { $code=3; } else { $code=4; }
-            $ctext.=' solved';
-        } elsif ($status eq 'correct_by_override') {
-            if ($code==0||$code==3) { $code=3; } else { $code=4; }
-            $ctext.=' override';
-        } elsif ($status eq 'incorrect_attempted') {
-            if ($code!=4 && $code!=3) { $code=2; }
-            if ($code==3) { $code=4; }
-            $ctext.=' ('.
-                ($returnhash{'resource.'.$_.'.tries'}?
-                 $returnhash{'resource.'.$_.'.tries'}:'0');
-            my $numtries = &parmval($_.'.maxtries',$symb);
-            if ($numtries) { $ctext.='/'.$numtries.' tries'; }
-            $ctext.=')';
-        } elsif ($status eq 'incorrect_by_override') {
-            if ($code!=4 && $code!=3) { $code=2; }
-            if ($code==3) { $code=4; }
-            $ctext.=' override';
-        } elsif ($status eq 'excused') {
-            if ($code==0||$code==3) { $code=3; } else { $code=4; }
-            $ctext.=' excused';
+        if ($res->duedate()) {
+            return &mt("Due")." " . timeToHumanString($res->duedate($part)) .
+                " $triesString";
         } else {
-            if ($code==0) { $code=1; }
+            return &mt("No due date")." $triesString";
         }
     }
+    if ($status == $res->ANSWER_SUBMITTED) {
+        return &mt('Answer submitted');
+    }
+}
+
+# Convenience function, so others can use it: Is the problem due in less then
+# 24 hours, and still can be done?
+
+sub dueInLessThen24Hours {
+    my $res = shift;
+    my $part = shift;
+    my $status = $res->status($part);
 
-    return 'p'.$code.$tcode.'"'.$ctext.'"';
+    return ($status == $res->OPEN() ||
+            $status == $res->TRIES_LEFT()) &&
+           $res->duedate() && $res->duedate() < time()+(24*60*60) &&
+           $res->duedate() > time();
 }
 
+# Convenience function, so others can use it: Is there only one try remaining for the
+# part, with more then one try to begin with, not due yet and still can be done?
+sub lastTry {
+    my $res = shift;
+    my $part = shift;
 
-sub addresource {
-    my ($resource,$sofar,$rid,$showtypes,$indent,$linkid)=@_;
-    if ($showtypes eq 'problems') {
-        if ($resource!~/\.(problem|exam|quiz|assess|survey|form)$/) {
-            return;
-        }
+    my $tries = $res->tries($part);
+    my $maxtries = $res->maxtries($part);
+    return $tries && $maxtries && $maxtries > 1 &&
+        $maxtries - $tries == 1 && $res->duedate() &&
+        $res->duedate() > time();
+}
+
+# This puts a human-readable name on the ENV variable.
+
+sub advancedUser {
+    return $ENV{'request.role.adv'};
+}
+
+
+# timeToHumanString takes a time number and converts it to a
+# human-readable representation, meant to be used in the following
+# manner:
+# print "Due $timestring"
+# print "Open $timestring"
+# print "Answer available $timestring"
+# Very, very, very, VERY English-only... goodness help a localizer on
+# this func...
+sub timeToHumanString {
+    my ($time) = @_;
+    # zero, '0' and blank are bad times
+    if (!$time) {
+        return &mt('never');
+    }
+    unless (&Apache::lonlocal::current_language()=~/^en/) {
+	return localtime($time);
+    } 
+    my $now = time();
+
+    my @time = localtime($time);
+    my @now = localtime($now);
+
+    # Positive = future
+    my $delta = $time - $now;
+
+    my $minute = 60;
+    my $hour = 60 * $minute;
+    my $day = 24 * $hour;
+    my $week = 7 * $day;
+    my $inPast = 0;
+
+    # Logic in comments:
+    # Is it now? (extremely unlikely)
+    if ( $delta == 0 ) {
+        return "this instant";
     }
-    my $brepriv=&Apache::lonnet::allowed('bre',$resource);
-    if ($hash{'src_'.$rid}) {
-        if (($brepriv eq '2') || ($brepriv eq 'F')) {
-            my $pprefix='';
-            if ($resource=~/\.(problem|exam|quiz|assess|survey|form)$/) {
-                $pprefix=&astatus($rid);
-            }
-            $$sofar++;
-            if ($indent) { $pprefix='i'.$indent.','.$pprefix; }
-            if ($linkid) { $pprefix='l'.$linkid.','.$pprefix; }
-            if (defined($rows[$$sofar])) {
-                $rows[$$sofar].='&'.$pprefix.$rid;
-            } else {
-                $rows[$$sofar]=$pprefix.$rid;
-            }
-        }
+
+    if ($delta < 0) {
+        $inPast = 1;
+        $delta = -$delta;
     }
-}
 
-sub followlinks () {
-    my ($rid,$sofar,$beenhere,$further,$showtypes,$indent,$linkid)=@_;
-    my $mincond=1;
-    my $next='';
-    foreach (split(/\,/,$hash{'to_'.$rid})) {
-        my $thiscond=
-            &Apache::lonnet::directcondval($hash{'condid_'.$hash{'undercond_'.$_}});
-        if ($thiscond>=$mincond) {
-            if ($next) {
-                $next.=','.$_.':'.$thiscond;
-            } else {
-                $next=$_.':'.$thiscond;
-            }
-            if ($thiscond>$mincond) { $mincond=$thiscond; }
+    if ( $delta > 0 ) {
+
+        my $tense = $inPast ? " ago" : "";
+        my $prefix = $inPast ? "" : "in ";
+        
+        # Less then a minute
+        if ( $delta < $minute ) {
+            if ($delta == 1) { return "${prefix}1 second$tense"; }
+            return "$prefix$delta seconds$tense";
         }
-    }
-    my $col=0;
-    &Apache::lonxml::debug("following links -$next-");
-    foreach (split(/\,/,$next)) {
-        my ($nextlinkid,$condval)=split(/\:/,$_);
-        if ($condval>=$mincond) {
-            my $now=&tracetable($sofar,$hash{'goesto_'.$nextlinkid},
-                                $beenhere,$showtypes,$indent,$linkid);
-            if ($now>$further) {                
-                if ($col>0) {
-                    my $string;
-                    for(my $i=0;$i<$col;$i++) { $string.='&'; }
-                    for(my $i=$further+1;$now-1>$i;$i++) {
-                        $rows[$i]=$string.$rows[$i];
-                    }
-                }
-                $further=$now;
+
+        # Less then an hour
+        if ( $delta < $hour ) {
+            # If so, use minutes
+            my $minutes = floor($delta / 60);
+            if ($minutes == 1) { return "${prefix}1 minute$tense"; }
+            return "$prefix$minutes minutes$tense";
+        }
+        
+        # Is it less then 24 hours away? If so,
+        # display hours + minutes
+        if ( $delta < $hour * 24) {
+            my $hours = floor($delta / $hour);
+            my $minutes = floor(($delta % $hour) / $minute);
+            my $hourString = "$hours hours";
+            my $minuteString = ", $minutes minutes";
+            if ($hours == 1) {
+                $hourString = "1 hour";
+            }
+            if ($minutes == 1) {
+                $minuteString = ", 1 minute";
+            }
+            if ($minutes == 0) {
+                $minuteString = "";
             }
+            return "$prefix$hourString$minuteString$tense";
         }
-        $col++;
-    }
-    return $further;
-}
-# ------------------------------------------------------------ Build page table
 
-sub tracetable {
-    my ($sofar,$rid,$beenhere,$showtypes,$indent,$linkid)=@_;
-    my $newshowtypes=$showtypes;
-    my $further=$sofar;
-# $Apache::lonxml::debug=1;
-    &Apache::lonxml::debug("$rid ; $linkid ; $sofar ; $beenhere ; ".$hash{'src_'.$rid});
-    if ($beenhere=~/\&$rid\&/) { return $further; }
-    $beenhere.=$rid.'&';
-
-    if (defined($hash{'is_map_'.$rid})) {
-        $sofar++;
-        my $tprefix='';
-        if ($hash{'map_type_'.$hash{'map_pc_'.$hash{'src_'.$rid}}}
-            eq 'sequence') {
-            $tprefix='h';
-        } elsif ($hash{'map_type_'.$hash{'map_pc_'.$hash{'src_'.$rid}}}
-                 eq 'page') {
-            $tprefix='j';
-            if ($indent) { $tprefix='i'.$indent.','.$tprefix; }
-            if ($linkid) { $tprefix='l'.$linkid.','.$tprefix; }
-            $newshowtypes='problems';
-            $indent++;
-            #if in a .page continue to link the encompising .page
-            if (!$linkid) { $linkid=$rid; }
+        # Less then 5 days away, display day of the week and
+        # HH:MM
+        if ( $delta < $day * 5 ) {
+            my $timeStr = strftime("%A, %b %e at %I:%M %P", localtime($time));
+            $timeStr =~ s/12:00 am/midnight/;
+            $timeStr =~ s/12:00 pm/noon/;
+            return ($inPast ? "last " : "next ") .
+                $timeStr;
         }
-        if (defined($rows[$sofar])) {
-            $rows[$sofar].='&'.$tprefix.$rid;
-        } else {
-            $rows[$sofar]=$tprefix.$rid;
-        }
-        if ((defined($hash{'map_start_'.$hash{'src_'.$rid}})) &&
-            (defined($hash{'map_finish_'.$hash{'src_'.$rid}}))) {
-            my $frid=$hash{'map_finish_'.$hash{'src_'.$rid}};
-            $sofar=&tracetable($sofar,$hash{'map_start_'.$hash{'src_'.$rid}},
-                               '&'.$frid.'&',$newshowtypes,$indent,$linkid);
-            &addresource($hash{'src_'.$frid},\$sofar,$frid,$newshowtypes,
-                         $indent,$linkid);
-            if ($tprefix =~ /j$/) { $indent--; $linkid=''; }
+        
+        # Is it this year?
+        if ( $time[5] == $now[5]) {
+            # Return on Month Day, HH:MM meridian
+            my $timeStr = strftime("on %A, %b %e at %I:%M %P", localtime($time));
+            $timeStr =~ s/12:00 am/midnight/;
+            $timeStr =~ s/12:00 pm/noon/;
+            return $timeStr;
         }
-    } else {
-        &addresource($hash{'src_'.$rid},\$sofar,$rid,$showtypes,
-                     $indent,$linkid);
-    }
 
-    if (defined($hash{'to_'.$rid})) {
-        $further=&followlinks($rid,$sofar,$beenhere,$further,$showtypes,
-                              $indent,$linkid);
+        # Not this year, so show the year
+        my $timeStr = strftime("on %A, %b %e %G at %I:%M %P", localtime($time));
+        $timeStr =~ s/12:00 am/midnight/;
+        $timeStr =~ s/12:00 pm/noon/;
+        return $timeStr;
     }
-
-    return $further;
 }
 
-# ================================================================ Main Handler
 
-sub handler {
-    my $r=shift;
+=pod
 
-    &Apache::loncommon::get_unprocessed_cgi($ENV{QUERY_STRING});
+=head1 NAME
 
-    if ($ENV{'form.jtest'} ne "1")
-    {
-        return new_handle($r);
-    }
+Apache::lonnavmap - Subroutines to handle and render the navigation
+    maps
 
-# ------------------------------------------- Set document type for header only
+=head1 SYNOPSIS
 
-    if ($r->header_only) {
-        if ($ENV{'browser.mathml'}) {
-            $r->content_type('text/xml');
-        } else {
-            $r->content_type('text/html');
-        }
-        $r->send_http_header;
-        return OK;
-    }
-    my $requrl=$r->uri;
-    my $hashtied;
-# ----------------------------------------------------------------- Tie db file
-    my $fn;
-    if ($ENV{'request.course.fn'}) {
-        $fn=$ENV{'request.course.fn'};
-        if (-e "$fn.db") {
-            if ((tie(%hash,'GDBM_File',"$fn.db",&GDBM_READER(),0640)) &&
-                (tie(%parmhash,'GDBM_File',
-                     $ENV{'request.course.fn'}.'_parms.db',
-                     &GDBM_READER(),0640))) {
-                $hashtied=1;
-            }
-        }
-    }
-    if (!$hashtied) {
-        $ENV{'user.error.msg'}="$requrl:bre:0:0:Course not initialized";
-        return HTTP_NOT_ACCEPTABLE; 
-    }
+The main handler generates the navigational listing for the course,
+the other objects export this information in a usable fashion for
+other modules.
+
+=head1 OVERVIEW
+
+X<lonnavmaps, overview> When a user enters a course, LON-CAPA examines the
+course structure and caches it in what is often referred to as the
+"big hash" X<big hash>. You can see it if you are logged into
+LON-CAPA, in a course, by going to /adm/test. (You may need to
+tweak the /home/httpd/lonTabs/htpasswd file to view it.) The
+content of the hash will be under the heading "Big Hash".
+
+Big Hash contains, among other things, how resources are related
+to each other (next/previous), what resources are maps, which 
+resources are being chosen to not show to the student (for random
+selection), and a lot of other things that can take a lot of time
+to compute due to the amount of data that needs to be collected and
+processed.
+
+Apache::lonnavmaps provides an object model for manipulating this
+information in a higher-level fashion then directly manipulating 
+the hash. It also provides access to several auxilary functions 
+that aren't necessarily stored in the Big Hash, but are a per-
+resource sort of value, like whether there is any feedback on 
+a given resource.
+
+Apache::lonnavmaps also abstracts away branching, and someday, 
+conditions, for the times where you don't really care about those
+things.
+
+Apache::lonnavmaps also provides fairly powerful routines for
+rendering navmaps, and last but not least, provides the navmaps
+view for when the user clicks the NAV button.
+
+B<Note>: Apache::lonnavmaps I<only> works for the "currently
+logged in user"; if you want things like "due dates for another
+student" lonnavmaps can not directly retrieve information like
+that. You need the EXT function. This module can still help,
+because many things, such as the course structure, are constant
+between users, and Apache::lonnavmaps can help by providing
+symbs for the EXT call.
+
+The rest of this file will cover the provided rendering routines, 
+which can often be used without fiddling with the navmap object at
+all, then documents the Apache::lonnavmaps::navmap object, which
+is the key to accessing the Big Hash information, covers the use
+of the Iterator (which provides the logic for traversing the 
+somewhat-complicated Big Hash data structure), documents the
+Apache::lonnavmaps::Resource objects that are returned by 
+
+=head1 Subroutine: render
+
+The navmap renderer package provides a sophisticated rendering of the
+standard navigation maps interface into HTML. The provided nav map
+handler is actually just a glorified call to this.
+
+Because of the large number of parameters this function accepts,
+instead of passing it arguments as is normal, pass it in an anonymous
+hash with the desired options.
+
+The package provides a function called 'render', called as
+Apache::lonnavmaps::render({}).
+
+=head2 Overview of Columns
+
+The renderer will build an HTML table for the navmap and return
+it. The table is consists of several columns, and a row for each
+resource (or possibly each part). You tell the renderer how many
+columns to create and what to place in each column, optionally using
+one or more of the prepared columns, and the renderer will assemble
+the table.
+
+Any additional generally useful column types should be placed in the
+renderer code here, so anybody can use it anywhere else. Any code
+specific to the current application (such as the addition of <input>
+elements in a column) should be placed in the code of the thing using
+the renderer.
+
+At the core of the renderer is the array reference COLS (see Example
+section below for how to pass this correctly). The COLS array will
+consist of entries of one of two types of things: Either an integer
+representing one of the pre-packaged column types, or a sub reference
+that takes a resource reference, a part number, and a reference to the
+argument hash passed to the renderer, and returns a string that will
+be inserted into the HTML representation as it.
 
-# ------------------------------------------------------------------- Hash tied
+All other parameters are ways of either changing how the columns
+are printing, or which rows are shown.
 
-    if ($ENV{'browser.mathml'}) {
-        $r->content_type('text/xml');
-    } else {
-        $r->content_type('text/html');
-    }
-    &Apache::loncommon::no_cache($r);
-    $r->send_http_header;
+The pre-packaged column names are refered to by constants in the
+Apache::lonnavmaps namespace. The following currently exist:
 
-    my $firstres=$hash{'map_start_'.
-           &Apache::lonnet::clutter($ENV{'request.course.uri'})};
-    my $lastres=$hash{'map_finish_'.
-           &Apache::lonnet::clutter($ENV{'request.course.uri'})};
-    if (!(($firstres) && ($lastres))) {
-        $r->print('<html><body>Coursemap undefined.</body></html>');
-    } else {
+=over 4
 
-# ----------------------------------------------------------------- Render page
-# -------------------------------------------------------------- Set parameters
+=item * B<Apache::lonnavmaps::resource>:
 
+The general info about the resource: Link, icon for the type, etc. The
+first column in the standard nav map display. This column provides the
+indentation effect seen in the B<NAV> screen. This column also accepts
+the following parameters in the renderer hash:
 
-# ---------------------------- initialize coursedata and userdata for this user
-        undef %courseopt;
-        undef %useropt;
-
-        my $uname=$ENV{'user.name'};
-        my $udom=$ENV{'user.domain'};
-        my $uhome=$ENV{'user.home'};
-        my $cid=$ENV{'request.course.id'};
-        my $chome=$ENV{'course.'.$cid.'.home'};
-        my ($cdom,$cnum)=split(/\_/,$cid);
+=over 4
 
-        my $userprefix=$uname.'_'.$udom.'_';
-        
-        unless ($uhome eq 'no_host') { 
-# ------------------------------------------------- Get coursedata (if present)
-            unless ((time-$courserdatas{$cid.'.last_cache'})<240) {
-                my $reply=&Apache::lonnet::reply('dump:'.$cdom.':'.$cnum.
-                                                 ':resourcedata',$chome);
-                if ($reply!~/^error\:/) {
-                    $courserdatas{$cid}=$reply;
-                    $courserdatas{$cid.'.last_cache'}=time;
-                }
-                # check to see if network failed
-                elsif ( $reply=~/no.such.host/i || $reply=~/con.*lost/i )
-                {
-                    $networkFailedFlag = 1;
-                }
-            }
-            foreach (split(/\&/,$courserdatas{$cid})) {
-                my ($name,$value)=split(/\=/,$_);
-                $courseopt{$userprefix.&Apache::lonnet::unescape($name)}=
-                    &Apache::lonnet::unescape($value);
-            }
-# --------------------------------------------------- Get userdata (if present)
-            unless ((time-$userrdatas{$uname.'___'.$udom.'.last_cache'})<240) {
-                my $reply=&Apache::lonnet::reply('dump:'.$udom.':'.$uname.':resourcedata',$uhome);
-                if ($reply!~/^error\:/) {
-                    $userrdatas{$uname.'___'.$udom}=$reply;
-                    $userrdatas{$uname.'___'.$udom.'.last_cache'}=time;
-                }
-            }
-            foreach (split(/\&/,$userrdatas{$uname.'___'.$udom})) {
-                my ($name,$value)=split(/\=/,$_);
-                $useropt{$userprefix.&Apache::lonnet::unescape($name)}=
-                    &Apache::lonnet::unescape($value);
-            }
-        }
+=item * B<resource_nolink>: default false
 
-        @rows=();
+If true, the resource will not be linked. By default, all non-folder
+resources are linked.
 
-        &tracetable(0,$firstres,'&','',0);
+=item * B<resource_part_count>: default true
 
-# ------------------------------------------------------------------ Page parms
+If true, the resource will show a part count B<if> the full
+part list is not displayed. (See "condense_parts" later.) If false,
+the resource will never show a part count.
 
-        my $j;
-        my $i;
-        my $lcm=1;
-        my $contents=0;
+=item * B<resource_no_folder_link>:
 
-# ---------------------------------------------- Go through table to get layout
+If true, the resource's folder will not be clickable to open or close
+it. Default is false. True implies printCloseAll is false, since you
+can't close or open folders when this is on anyhow.
 
-        for ($i=0;$i<=$#rows;$i++) {
-            if ($rows[$i]) {
-                &Apache::lonxml::debug("Row $i is:".$rows[$i]);
-                $contents++;
-                my @colcont=split(/\&/,$rows[$i]);
-                $lcm*=($#colcont+1)/euclid($lcm,($#colcont+1));
-            } 
-        }
+=back
 
+=item * B<Apache::lonnavmaps::communication_status>:
 
-        unless ($contents) {
-            $r->print('<html><body>Empty Map.</body></html>');
-        } else {
+Whether there is discussion on the resource, email for the user, or
+(lumped in here) perl errors in the execution of the problem. This is
+the second column in the main nav map.
 
-# ------------------------------------------------------------------ Build page
+=item * B<Apache::lonnavmaps::quick_status>:
 
-            my $currenturl=$ENV{'form.postdata'};
-            $currenturl=~s/^http\:\/\///;
-            $currenturl=~s/^[^\/]+//;
-
-# ---------------------------------------------------------------- Send headers
-
-            my $date=localtime;
-            my $now=time;
-# ----------------------------------------- Get email status and discussiontime
-
-            my %emailstatus=&Apache::lonnet::dump('email_status');
-            my $logouttime=$emailstatus{'logout'};
-            my $courseleave=$emailstatus{'logout_'.$ENV{'request.course.id'}};
-            my $lastcheck=($courseleave>$logouttime?$courseleave:$logouttime);
-
-            my %discussiontimes=&Apache::lonnet::dump('discussiontimes',
-                                                          $cdom,$cnum);
-
-            my %feedback=();
-            my %error=();
-            foreach my $msgid (split(/\&/,&Apache::lonnet::reply('keys:'.
-                                                                 $ENV{'user.domain'}.':'.
-                                                                 $ENV{'user.name'}.':nohist_email',
-                                                                 $ENV{'user.home'}))) {
-                $msgid=&Apache::lonnet::unescape($msgid);
-                my $plain=&Apache::lonnet::unescape(&Apache::lonnet::unescape($msgid));
-                if ($plain=~/(Error|Feedback) \[([^\]]+)\]/) {
-                    my ($what,$url)=($1,$2);
-                    my %status=
-                        &Apache::lonnet::get('email_status',[$msgid]);
-                    if ($status{$msgid}=~/^error\:/) { 
-                        $status{$msgid}=''; 
-                    }
-                        
-                    if (($status{$msgid} eq 'new') || 
-                        (!$status{$msgid})) { 
-                        if ($what eq 'Error') {
-                            $error{$url}.=','.$msgid; 
-                        } else {
-                            $feedback{$url}.=','.$msgid;
-                        }
-                    }
-                }
-            }
-# ----------------------------------------------------------- Start Page Output
-            my $bodytagadd='';
-            $r->print(
-                   '<html><head><title>Navigate Course Map</title></head>');
-            if (($currenturl=~/^\/res/) &&
-                ($currenturl!~/^\/res\/adm/)) {
-                $bodytagadd='onLoad="window.location.hash='."'curloc'".'"';
-            }
-            $r->print(&Apache::loncommon::bodytag('Navigate Course Map','',
-                                                  $bodytagadd));
-            $r->print('<script>window.focus();</script>');
-            my $desc=$ENV{'course.'.$ENV{'request.course.id'}.'.description'};
-            if (defined($desc)) { $r->print("<h2>$desc</h2>\n"); }
-            $r->print("<h3>$date</h3>\n");
-            $r->rflush();
-            $r->print('<img src="/adm/lonMisc/chat.gif"> New discussion since '.
-                      localtime($lastcheck).
-                      '<br><img src="/adm/lonMisc/feedback.gif"> New message (click to open)<p>'); 
-            if (($currenturl=~/^\/res/) &&
-                ($currenturl!~/^\/res\/adm/)) {
-                $r->print('<a href="#curloc">Current Location</a><p>');
-            }
+An icon for the status of a problem, with five possible states:
+Correct, incorrect, open, awaiting grading (for a problem where the
+computer's grade is suppressed, or the computer can't grade, like
+essay problem), or none (not open yet, not a problem). The
+third column of the standard navmap.
 
-            # Handle a network error
+=item * B<Apache::lonnavmaps::long_status>:
 
-            if ($networkFailedFlag)
-            {
-                $r->print('<H2>LON-CAPA network failure.</H2>'."\n");
-                $r->print("<p>LON-CAPA's network is having difficulties, some problem" .
-                          " information, such as due dates, will not be available.");
-            }
-# ----------------------------------------------------- The little content list
-            for ($i=0;$i<=$#rows;$i++) {
-                if ($rows[$i]) {
-                    my @colcont=split(/\&/,$rows[$i]);
-                    my $avespan=$lcm/($#colcont+1);
-                    for ($j=0;$j<=$#colcont;$j++) {
-                        my $rid=$colcont[$j];
-                        if ($rid=~/^h(.+)/) {
-                            $rid=$1;
-                            $r->print('&nbsp;&nbsp;&nbsp;<a href="#'.
-                                      $rid.'">'.$hash{'title_'.$rid}.
-                                      '</a><br>');
-                        }
-                    }
-                }
-            }
-# ----------------------------------------------------------------- Start table
-            $r->print('<hr><table cols="'.$lcm.'" border="0">');
-            for ($i=0;$i<=$#rows;$i++) {
-                if ($rows[$i]) {
-                    $r->print("\n<tr>");
-                    my @colcont=split(/\&/,$rows[$i]);
-                    my $avespan=$lcm/($#colcont+1);
-
-                    # for each item I wish to print on this row...
-                    for ($j=0;$j<=$#colcont;$j++) {
-                        my $indent;my $indentstr;
-                        my $linkid;
-                        my $rid=$colcont[$j];
-                        $rid=~/(\d+)\.(\d+)$/;
-                        my $src=
-                           &Apache::lonnet::declutter($hash{'src_'.$1.'.'.$2});
-                        my $symb=
-          &Apache::lonnet::declutter($hash{'map_id_'.$1}).'___'.$2.'___'.$src;
-                        my $add='<td>';
-                        my $adde='</td>';
-                        my $hwk='<font color="#223322">';
-                        my $hwke='</font>';
-                        if ($rid=~/^l(\d+\.\d+),(.+)/) { $linkid=$1; $rid=$2; }
-                        if ($rid=~/^i(\d+),(.+)/) { $indent=$1; $rid=$2; }
-                        if ($rid=~/^h(.+)/) {
-                            $rid=$1;
-                            $add='<th bgcolor="#AAFF55"><a name="'.$rid.'">';
-                            $adde='</th>';
-                            if (($ENV{'user.adv'}) && 
-                                ($parmhash{$symb.'.0.parameter_randompick'})) {
-                               $adde=' (randomly select '.
-                                   $parmhash{$symb.'.0.parameter_randompick'}.
-                                   ')</th>';
-                            }
-                        }
-                        if ($rid=~/^j(.+)/) { $rid=$1; }
-                        if ($rid=~/^p(\d)(\d)\"([\w\: \(\)\/\,]*)\"(.+)/) {
-                            # sub astatus describes what code/tcode mean
-                            my $code=$1;
-                            my $tcode=$2;
-                            my $ctext=$3;
-                            $rid=$4;
-                            
-                            # will open later
-                            if ($tcode eq '1') { 
-                                $add='<td bgcolor="#AAAAAA">';
-                            }
-
-                            # solved/correct
-                            if ($code eq '3') {
-                                $add='<td bgcolor="#AAFFAA">';
-                            } elsif ($code eq '4') { # partially correct
-                                $add='<td bgcolor="#E0FFAA">';
-                            } else {
-                                # not attempted
-                                
-                                # we end up here on network failure, so pick a neutral
-                                # color if the network failed instead of bright red.
-                                if ( $networkFailedFlag )
-                                {
-                                    $add = '<td bgcolor="#AAAAAA">';
-                                }
-                                else
-                                {
-                                    $add='<td bgcolor="#FFAAAA">';
-                                }
-
-                                if ($tcode eq '2') { # open, not past due
-                                    $add='<td bgcolor="#FFFFAA">';
-                                }
-
-                                if ($tcode eq '4') { # due in next 24 hours
-                                    $add='<td bgcolor="#FFFF33">';
-                                    $adde='</td>';
-                                }
-                            }
-                            $hwk='<font color="#888811"><b>';
-                            $hwke='</b></font>';
-                            if ($code eq '1') {
-                                $hwke='</b> ('.$ctext.')</font>';
-                            }
-                            if ($code eq '2' || $code eq '4') {
-                                $hwk='<font color="#992222"><b>';
-                                $hwke='</b> ('.$ctext.')</font>';
-                            }
-                            if ($code eq '3') {
-                                $hwk='<font color="#229922"><b>';
-                                $hwke='</b> ('.$ctext.')</font>';
-                            }
-                            if ($networkFailedFlag) 
-                            {
-                                $hwke='</b> (status unavailable)</font>';
-                            }
-                        }
-                        if ($rid && $hash{'src_'.$rid} eq $currenturl) {
-                            $add=$add.'<a name="curloc"></a>'.
-                                '<font color=red size=+2><b>&gt; </b></font>';
-                            $adde=
-                                '<font color=red size=+2><b> &lt;</b></font>'.$adde;
-                        }
-                        if ($discussiontimes{$symb}>$lastcheck) {
-                            $adde=
-                                '<img border=0 src="/adm/lonMisc/chat.gif">'.
-                                    $adde;
-                        }
-                        if ($error{$src}) {
-                            foreach (split(/\,/,$error{$src})) {
-                                if ($_) {
-                                    $adde=
-                                        '&nbsp;<a href="/adm/email?display='.
-                                            &Apache::lonnet::escape($_).
-                                                '"><img src="/adm/lonMisc/bomb.gif" border=0></a>'
-                                                    .$adde;
-                                }
-                            }
-                        }
-                        if ($feedback{$src}) {
-                            foreach (split(/\,/,$feedback{$src})) {
-                                if ($_) {
-                                    $adde=
-                                        '&nbsp;<a href="/adm/email?display='.
-                                            &Apache::lonnet::escape($_).
-                                                '"><img src="/adm/lonMisc/feedback.gif" border=0></a>'
-                                                    .$adde;
-                                }
-                            }
-                        }
-                        if ($indent) {
-                            my $is="&nbsp;&nbsp;";
-                            for(my $i=-1;$i<$indent;$i++) { $indentstr.=$is; }
-                        }
-                        if (!$linkid) { $linkid=$rid; }
-                        if ($hash{'randomout_'.$rid}) {
-                            $adde=' <i>(hidden)</i>'.$adde;
-                        }
-                        $r->print($add.$indentstr);
-                        if ($rid) {
-                            $r->print('<a href="'.$hash{'src_'.$linkid}.
-                                      (($hash{'src_'.$linkid}=~/\?/)?'&':'?').
-                                      'symb='.&Apache::lonnet::escape($symb)
-                                       .'">'.
-                                      $hwk.$hash{'title_'.$rid}.$hwke.'</a>');
-                        }
-                        $r->print($adde);
-                    }
-                    $r->print('</tr>');
-                }
-            }
-            $r->print("\n</table>");
-            $r->print('</body></html>');
-# -------------------------------------------------------------------- End page
-        }                  
-# ------------------------------------------------------------- End render page
-    }
-# ------------------------------------------------------------------ Untie hash
-    unless (untie(%hash)) {
-        &Apache::lonnet::logthis("<font color=blue>WARNING: ".
-                                 "Could not untie coursemap $fn (browse).</font>"); 
-    }
-    unless (untie(%parmhash)) {
-        &Apache::lonnet::logthis("<font color=blue>WARNING: ".
-                                 "Could not untie parmhash (browse).</font>"); 
+A text readout of the details of the current status of the problem,
+such as "Due in 22 hours". The fourth column of the standard navmap.
+
+=item * B<Apache::lonnavmaps::part_status_summary>:
+
+A text readout summarizing the status of the problem. If it is a
+single part problem, will display "Correct", "Incorrect", 
+"Not yet open", "Open", "Attempted", or "Error". If there are
+multiple parts, this will output a string that in HTML will show a
+status of how many parts are in each status, in color coding, trying
+to match the colors of the icons within reason.
+
+Note this only makes sense if you are I<not> showing parts. If 
+C<showParts> is true (see below), this column will not output
+anything. 
+
+=back
+
+If you add any others please be sure to document them here.
+
+An example of a column renderer that will show the ID number of a
+resource, along with the part name if any:
+
+ sub { 
+  my ($resource, $part, $params) = @_;   
+  if ($part) { return '<td>' . $resource->{ID} . ' ' . $part . '</td>'; }
+  return '<td>' . $resource->{ID} . '</td>';
+ }
+
+Note these functions are responsible for the TD tags, which allow them
+to override vertical and horizontal alignment, etc.
+
+=head2 Parameters
+
+Minimally, you should be
+able to get away with just using 'cols' (to specify the columns
+shown), 'url' (necessary for the folders to link to the current screen
+correctly), and possibly 'queryString' if your app calls for it. In
+that case, maintaining the state of the folders will be done
+automatically.
+
+=over 4
+
+=item * B<iterator>: default: constructs one from %ENV
+
+A reference to a fresh ::iterator to use from the navmaps. The
+rendering will reflect the options passed to the iterator, so you can
+use that to just render a certain part of the course, if you like. If
+one is not passed, the renderer will attempt to construct one from
+ENV{'form.filter'} and ENV{'form.condition'} information, plus the
+'iterator_map' parameter if any.
+
+=item * B<iterator_map>: default: not used
+
+If you are letting the renderer do the iterator handling, you can
+instruct the renderer to render only a particular map by passing it
+the source of the map you want to process, like
+'/res/103/jerf/navmap.course.sequence'.
+
+=item * B<navmap>: default: constructs one from %ENV
+
+A reference to a navmap, used only if an iterator is not passed in. If
+this is necessary to make an iterator but it is not passed in, a new
+one will be constructed based on ENV info. This is useful to do basic
+error checking before passing it off to render.
+
+=item * B<r>: default: must be passed in
+
+The standard Apache response object. This must be passed to the
+renderer or the course hash will be locked.
+
+=item * B<cols>: default: empty (useless)
+
+An array reference
+
+=item * B<showParts>:default true
+
+A flag. If true, a line for the resource itself, and a line
+for each part will be displayed. If not, only one line for each
+resource will be displayed.
+
+=item * B<condenseParts>: default true
+
+A flag. If true, if all parts of the problem have the same
+status and that status is Nothing Set, Correct, or Network Failure,
+then only one line will be displayed for that resource anyhow. If no,
+all parts will always be displayed. If showParts is 0, this is
+ignored.
+
+=item * B<jumpCount>: default: determined from %ENV
+
+A string identifying the URL to place the anchor 'curloc' at.
+It is the responsibility of the renderer user to
+ensure that the #curloc is in the URL. By default, determined through
+the use of the ENV{} 'jump' information, and should normally "just
+work" correctly.
+
+=item * B<here>: default: empty string
+
+A Symb identifying where to place the 'here' marker. The empty
+string means no marker.
+
+=item * B<indentString>: default: 25 pixel whitespace image
+
+A string identifying the indentation string to use. 
+
+=item * B<queryString>: default: empty
+
+A string which will be prepended to the query string used when the
+folders are opened or closed. You can use this to pass
+application-specific values.
+
+=item * B<url>: default: none
+
+The url the folders will link to, which should be the current
+page. Required if the resource info column is shown, and you 
+are allowing the user to open and close folders.
+
+=item * B<currentJumpIndex>: default: no jumping
+
+Describes the currently-open row number to cause the browser to jump
+to, because the user just opened that folder. By default, pulled from
+the Jump information in the ENV{'form.*'}.
+
+=item * B<printKey>: default: false
+
+If true, print the key that appears on the top of the standard
+navmaps.
+
+=item * B<printCloseAll>: default: true
+
+If true, print the "Close all folders" or "open all folders"
+links.
+
+=item * B<filterFunc>: default: sub {return 1;} (accept everything)
+
+A function that takes the resource object as its only parameter and
+returns a true or false value. If true, the resource is displayed. If
+false, it is simply skipped in the display.
+
+=item * B<suppressEmptySequences>: default: false
+
+If you're using a filter function, and displaying sequences to orient
+the user, then frequently some sequences will be empty. Setting this to
+true will cause those sequences not to display, so as not to confuse the
+user into thinking that if the sequence is there there should be things
+under it; for example, see the "Show Uncompleted Homework" view on the
+B<NAV> screen.
+
+=item * B<suppressNavmaps>: default: false
+
+If true, will not display Navigate Content resources. 
+
+=back
+
+=head2 Additional Info
+
+In addition to the parameters you can pass to the renderer, which will
+be passed through unchange to the column renderers, the renderer will
+generate the following information which your renderer may find
+useful:
+
+=over 4
+
+=item * B<counter>: 
+
+Contains the number of rows printed. Useful after calling the render 
+function, as you can detect whether anything was printed at all.
+
+=item * B<isNewBranch>:
+
+Useful for renderers: If this resource is currently the first resource
+of a new branch, this will be true. The Resource column (leftmost in the
+navmaps screen) uses this to display the "new branch" icon 
+
+=back
+
+=cut
+
+sub resource { return 0; }
+sub communication_status { return 1; }
+sub quick_status { return 2; }
+sub long_status { return 3; }
+sub part_status_summary { return 4; }
+
+sub render_resource {
+    my ($resource, $part, $params) = @_;
+
+    my $nonLinkedText = ''; # stuff after resource title not in link
+
+    my $link = $params->{"resourceLink"};
+    my $src = $resource->src();
+    my $it = $params->{"iterator"};
+    my $filter = $it->{FILTER};
+
+    my $title = $resource->compTitle();
+    if ($src =~ /^\/uploaded\//) {
+        $nonLinkedText=$title;
+        $title = '';
+    }
+    my $partLabel = "";
+    my $newBranchText = "";
+    
+    # If this is a new branch, label it so
+    if ($params->{'isNewBranch'}) {
+        $newBranchText = "<img src='/adm/lonIcons/branch.gif' border='0' />";
     }
-    return OK;
-}
 
-sub new_handle {
-    my $r = shift;
+    # links to open and close the folder
+    my $linkopen = "<a href='$link'>";
+    my $linkclose = "</a>";
 
-    # Handle header-only request
-    if ($r->header_only) {
-        if ($ENV{'browser.mathml'}) {
-            $r->content_type('text/xml');
+    # Default icon: unknown page
+    my $icon = "<img src='/adm/lonIcons/unknown.gif' alt='' border='0' />";
+    
+    if ($resource->is_problem()) {
+        if ($part eq '0' || $params->{'condensed'}) {
+            $icon = '<img src="/adm/lonIcons/problem.gif" alt="" border="0" />';
         } else {
-            $r->content_type('text/html');
+            $icon = $params->{'indentString'};
         }
-        $r->send_http_header;
-        return OK;
+    } else {
+	my $curfext= (split (/\./,$resource->src))[-1];
+	my $embstyle = &Apache::loncommon::fileembstyle($curfext);
+	# The unless conditional that follows is a bit of overkill
+	if (!(!defined($embstyle) || $embstyle eq 'unk' || $embstyle eq 'hdn')) {
+	    $icon = "<img src='/adm/lonIcons/$curfext.gif' alt='' border='0' />";
+	}
     }
 
-    # Send header, don't cache this page
-    if ($ENV{'browser.mathml'}) {
-        $r->content_type('text/xml');
-    } else {
-        $r->content_type('text/html');
+    # Display the correct map icon to open or shut map
+    if ($resource->is_map()) {
+        my $mapId = $resource->map_pc();
+        my $nowOpen = !defined($filter->{$mapId});
+        if ($it->{CONDITION}) {
+            $nowOpen = !$nowOpen;
+        }
+
+	my $folderType = $resource->is_sequence() ? 'folder' : 'page';
+
+        if (!$params->{'resource_no_folder_link'}) {
+            $icon = "navmap.$folderType." . ($nowOpen ? 'closed' : 'open') . '.gif';
+            $icon = "<img src='/adm/lonIcons/$icon' alt='' border='0' />";
+
+            $linkopen = "<a href='" . $params->{'url'} . '?' . 
+                $params->{'queryString'} . '&filter=';
+            $linkopen .= ($nowOpen xor $it->{CONDITION}) ?
+                addToFilter($filter, $mapId) :
+                removeFromFilter($filter, $mapId);
+            $linkopen .= "&condition=" . $it->{CONDITION} . '&hereType='
+                . $params->{'hereType'} . '&here=' .
+                &Apache::lonnet::escape($params->{'here'}) . 
+                '&jump=' .
+                &Apache::lonnet::escape($resource->symb()) . 
+                "&folderManip=1'>";
+        } else {
+            # Don't allow users to manipulate folder
+            $icon = "navmap.$folderType." . ($nowOpen ? 'closed' : 'open') .
+                '.nomanip.gif';
+            $icon = "<img src='/adm/lonIcons/$icon' alt='' border='0' />";
+
+            $linkopen = "";
+            $linkclose = "";
+        }
     }
-    &Apache::loncommon::no_cache($r);
-    $r->send_http_header;
 
-    # Header
-    $r->print(&Apache::loncommon::bodytag('Navigate Course Map','',
-                                          ''));
-    # Initialize the nav map
-    my $navmap = Apache::lonnavmaps::navmap->new(
-                        $ENV{"request.course.fn"}.".db",
-                        $ENV{"request.course.fn"}."_parms.db", 1);
+    if ($resource->randomout()) {
+        $nonLinkedText .= ' <i>(hidden)</i> ';
+    }
+    
+    # We're done preparing and finally ready to start the rendering
+    my $result = "<td align='left' valign='center'>";
 
+    my $indentLevel = $params->{'indentLevel'};
+    if ($newBranchText) { $indentLevel--; }
 
-    if (!defined($navmap)) {
-        my $requrl = $r->uri;
-        $ENV{'user.error.msg'} = "$requrl:bre:0:0:Course not initialized";
-        return HTTP_NOT_ACCEPTABLE;
+    # print indentation
+    for (my $i = 0; $i < $indentLevel; $i++) {
+        $result .= $params->{'indentString'};
     }
 
-    # Check that it's defined
-    if (!($navmap->courseMapDefined())) {
-        $r->print('<font size="+2" color="red">Coursemap undefined.</font>' .
-                  '</body></html>');
-        return OK;
+    # Decide what to display
+    $result .= "$newBranchText$linkopen$icon$linkclose";
+    
+    my $curMarkerBegin = '';
+    my $curMarkerEnd = '';
+
+    # Is this the current resource?
+    if (!$params->{'displayedHereMarker'} && 
+        $resource->symb() eq $params->{'here'} ) {
+        $curMarkerBegin = '<font color="red" size="+2">&gt; </font>';
+        $curMarkerEnd = '<font color="red" size="+2">&lt;</font>';
+        $params->{'displayedHereMarker'} = 1;
     }
 
-    # Grab a resource object so we have access to the constants; this
-    # is technically not proper, but should be harmless
-    my $res = $navmap->firstResource();
-
-    # Defines a status->color mapping, null string means don't color
-    my %colormap = 
-    ( $res->NETWORK_FAILURE        => '',
-      $res->CORRECT                => '#BBFFBB',
-      $res->EXCUSED                => '#BBBBFF',
-      $res->PAST_DUE_ANSWER_LATER  => '#FFAA00',
-      $res->PAST_DUE_NO_ANSWER     => '#FFAA00',
-      $res->ANSWER_OPEN            => '#FF00AA',
-      $res->OPEN_LATER             => '',
-      $res->TRIES_LEFT             => '#FFFF00',
-      $res->INCORRECT              => '#FFAA00',
-      $res->OPEN                   => '#FFFF88',
-      $res->NOTHING_SET            => ''        );
+    if ($resource->is_problem() && $part ne '0' && 
+        !$params->{'condensed'}) {
+        $partLabel = " (Part $part)";
+        $title = "";
+    }
 
-    my %filterHash;
-    # Figure out what we're not displaying
-    foreach (split(/\,/, $ENV{"form.filter"})) {
-        if ($_) {
-            $filterHash{$_} = "1";
-        }
+    if ($params->{'condensed'} && $resource->countParts() > 1) {
+        $nonLinkedText .= ' (' . $resource->countParts() . ' parts)';
+    }
+
+    if (!$params->{'resource_nolink'} && $src !~ /^\/uploaded\// &&
+	!$resource->is_sequence()) {
+        $result .= "  $curMarkerBegin<a href='$link'>$title$partLabel</a>$curMarkerEnd $nonLinkedText</td>";
+    } else {
+        $result .= "  $curMarkerBegin$title$partLabel$curMarkerEnd $nonLinkedText</td>";
     }
 
-    # Begin the HTML table
-    # two columns: the title/icon on the left, the info on the right
-    $r->print('<table cellspacing="3" cellpadding="0" bgcolor="#FFFFFF">' ."\n");
+    return $result;
+}
 
-    my $mapIterator = $navmap->getIterator(undef, undef, \%filterHash);
-    my $curRes = $mapIterator->next();
-    undef $res; # so we don't accidentally use it later
-    my $indentLevel = -1;
-    my $indentString = "&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;";
+sub render_communication_status {
+    my ($resource, $part, $params) = @_;
+    my $discussionHTML = ""; my $feedbackHTML = ""; my $errorHTML = "";
 
-    my $isNewBranch = 0;
+    my $link = $params->{"resourceLink"};
+    my $linkopen = "<a href='$link'>";
+    my $linkclose = "</a>";
 
-    while ($curRes != $mapIterator->END_NAV_MAP) {
-        if ($curRes == $mapIterator->BEGIN_MAP() ||
-            $curRes == $mapIterator->BEGIN_BRANCH()) {
-            $indentLevel++;
-        }
-        if ($curRes == $mapIterator->END_MAP() ||
-            $curRes == $mapIterator->END_BRANCH()) {
-            $indentLevel--;
+    if ($resource->hasDiscussion()) {
+        $discussionHTML = $linkopen .
+            '<img border="0" src="/adm/lonMisc/chat.gif" />' .
+            $linkclose;
+    }
+    
+    if ($resource->getFeedback()) {
+        my $feedback = $resource->getFeedback();
+        foreach (split(/\,/, $feedback)) {
+            if ($_) {
+                $feedbackHTML .= '&nbsp;<a href="/adm/email?display='
+                    . &Apache::lonnet::escape($_) . '">'
+                    . '<img src="/adm/lonMisc/feedback.gif" '
+                    . 'border="0" /></a>';
+            }
         }
-        if ($curRes == $mapIterator->BEGIN_BRANCH()) {
-            $isNewBranch = 1;
+    }
+    
+    if ($resource->getErrors()) {
+        my $errors = $resource->getErrors();
+        foreach (split(/,/, $errors)) {
+            if ($_) {
+                $errorHTML .= '&nbsp;<a href="/adm/email?display='
+                    . &Apache::lonnet::escape($_) . '">'
+                    . '<img src="/adm/lonMisc/bomb.gif" '
+                    . 'border="0" /></a>';
+            }
         }
+    }
+
+    if ($params->{'multipart'} && $part != '0') {
+	$discussionHTML = $feedbackHTML = $errorHTML = '';
+    }
 
-        if (ref($curRes) && $curRes->src()) {
+    return "<td width=\"75\" align=\"left\" valign=\"center\">$discussionHTML$feedbackHTML$errorHTML&nbsp;</td>";
 
-            my @parts;
-            if ($curRes->is_problem()) {
-                @parts = @{$curRes->parts()};
-                if (scalar(@parts) > 1) { shift(@parts); }
-            } else {
-                @parts[0] = "0"; # this is to get past foreach loop below
-                 # you can consider a non-problem resource as a resource
-                 # with only one part without loss
-            }
+}
+sub render_quick_status {
+    my ($resource, $part, $params) = @_;
+    my $result = "";
+    my $firstDisplayed = !$params->{'condensed'} && 
+        $params->{'multipart'} && $part eq "0";
+
+    my $link = $params->{"resourceLink"};
+    my $linkopen = "<a href='$link'>";
+    my $linkclose = "</a>";
+
+    if ($resource->is_problem() &&
+        !$firstDisplayed) {
+	
+        my $icon = $statusIconMap{$resource->simpleStatus($part)};
+        my $alt = $iconAltTags{$icon};
+        if ($icon) {
+            $result .= "<td width='30' valign='center' width='50' align='right'>$linkopen<img width='25' height='25' src='/adm/lonIcons/$icon' border='0' alt='$alt' />$linkclose</td>\n";
+        } else {
+            $result .= "<td width='30'>&nbsp;</td>\n";
+        }
+    } else { # not problem, no icon
+        $result .= "<td width='30'>&nbsp;</td>\n";
+    }
 
-            foreach my $part (@parts) {
+    return $result;
+}
+sub render_long_status {
+    my ($resource, $part, $params) = @_;
+    my $result = "<td align='right' valign='center'>\n";
+    my $firstDisplayed = !$params->{'condensed'} && 
+        $params->{'multipart'} && $part eq "0";
                 
-                # For each thing we're displaying...
+    my $color;
+    if ($resource->is_problem()) {
+        $color = $colormap{$resource->status};
+        
+        if (dueInLessThen24Hours($resource, $part) ||
+            lastTry($resource, $part)) {
+            $color = $hurryUpColor;
+        }
+    }
+    
+    if ($resource->kind() eq "res" &&
+        $resource->is_problem() &&
+        !$firstDisplayed) {
+        if ($color) {$result .= "<font color=\"$color\"><b>"; }
+        $result .= getDescription($resource, $part);
+        if ($color) {$result .= "</b></font>"; }
+    }
+    if ($resource->is_map() && advancedUser() && $resource->randompick()) {
+        $result .= '(randomly select ' . $resource->randompick() .')';
+    }
+
+    # Debugging code
+    #$result .= " " . $resource->awarded($part) . '/' . $resource->weight($part) .
+    #	' - Part: ' . $part;
 
-                my $stack = $mapIterator->getStack();
-                my $src = getLinkForResource($stack);
+    $result .= "</td>\n";
+    
+    return $result;
+}
 
-                my $srcHasQuestion = $src =~ /\?/;
-                my $link = $src.
-                    ($srcHasQuestion?'&':'?') .
-                    'symb='.&Apache::lonnet::escape($curRes->symb()).
-                    '"';
-                my $title = $curRes->title();
-                my $partLabel = "";
-                my $newBranchText = "";
-
-                # If this is a new branch, label it so
-                # (temporary, this should be an icon w/ alt text)
-                if ($isNewBranch) {
-                    $newBranchText = "NB -> ";
-                    $isNewBranch = 0;
-                }
+# Colors obtained by taking the icons, matching the colors, and
+# possibly reducing the Value (HSV) of the color, if it's too bright
+# for text, generally by one third or so.
+my %statusColors = 
+    (
+     $resObj->CLOSED => '#000000',
+     $resObj->OPEN   => '#998b13',
+     $resObj->CORRECT => '#26933f',
+     $resObj->INCORRECT => '#c48207',
+     $resObj->ATTEMPTED => '#a87510',
+     $resObj->ERROR => '#000000'
+     );
+my %statusStrings = 
+    (
+     $resObj->CLOSED => 'Not yet open',
+     $resObj->OPEN   => 'Open',
+     $resObj->CORRECT => 'Correct',
+     $resObj->INCORRECT => 'Incorrect',
+     $resObj->ATTEMPTED => 'Attempted',
+     $resObj->ERROR => 'Network Error'
+     );
+my @statuses = ($resObj->CORRECT, $resObj->ATTEMPTED, $resObj->INCORRECT, $resObj->OPEN, $resObj->CLOSED, $resObj->ERROR);
+
+use Data::Dumper;
+sub render_parts_summary_status {
+    my ($resource, $part, $params) = @_;
+    if (!$resource->is_problem()) { return '<td></td>'; }
+    if ($params->{showParts}) { 
+	return '<td></td>';
+    }
+
+    my $td = "<td align='right'>\n";
+    my $endtd = "</td>\n";
+
+    # If there is a single part, just show the simple status
+    if ($resource->singlepart()) {
+	my $status = $resource->simpleStatus('0');
+	return $td . "<font color='" . $statusColors{$status} . "'>"
+	    . $statusStrings{$status} . "</font>" . $endtd;
+    }
+
+    # Now we can be sure the $part doesn't really matter.
+    my $statusCount = $resource->simpleStatusCount();
+    my @counts;
+    foreach my $status(@statuses) {
+	# decouple display order from the simpleStatusCount order
+	my $slot = Apache::lonnavmaps::resource::statusToSlot($status);
+	if ($statusCount->[$slot]) {
+	    push @counts, "<font color='" . $statusColors{$status} .
+		"'>" . $statusCount->[$slot] . ' '
+		. $statusStrings{$status} . "</font>";
+	}
+    }
+
+    return $td . $resource->countParts() . ' parts: ' . join (', ', @counts) . $endtd;
+}
+
+my @preparedColumns = (\&render_resource, \&render_communication_status,
+                       \&render_quick_status, \&render_long_status,
+		       \&render_parts_summary_status);
+
+sub setDefault {
+    my ($val, $default) = @_;
+    if (!defined($val)) { return $default; }
+    return $val;
+}
 
-                # links to open and close the folders
-                my $linkopen = "<a href=\"$link\">";
-                my $linkclose = "</a>";
-
-                my $icon = "html.gif";
-                if ($curRes->is_problem()) { 
-                    $icon = "problem.gif"; 
-                }
+sub render {
+    my $args = shift;
+    &Apache::loncommon::get_unprocessed_cgi($ENV{QUERY_STRING});
+    my $result = '';
 
-                # Display the correct icon, link to open or shut map
-                if ($curRes->is_map()) { 
-                    my $mapId = $curRes->map_pc();
-                    my $nowOpen = !defined($filterHash{$mapId});
-                    $icon = $nowOpen ?
-                        "folder_opened.gif" : "folder_closed.gif";
-                    $linkopen = "<a href=\"/adm/navmaps?filter=";
-                    $linkopen .= $nowOpen ? 
-                        addToFilter(\%filterHash, $mapId) :
-                        removeFromFilter(\%filterHash, $mapId);
-                    $linkopen .= "\">";
-                    $linkclose = "</a>";
-                    
-                }
+    # Configure the renderer.
+    my $cols = $args->{'cols'};
+    if (!defined($cols)) {
+        # no columns, no nav maps.
+        return '';
+    }
+    my $mustCloseNavMap = 0;
+    my $navmap;
+    if (defined($args->{'navmap'})) {
+        $navmap = $args->{'navmap'};
+    }
+
+    my $r = $args->{'r'};
+    my $queryString = $args->{'queryString'};
+    my $jump = $args->{'jump'};
+    my $here = $args->{'here'};
+    my $suppressNavmap = setDefault($args->{'suppressNavmap'}, 0);
+    my $currentJumpDelta = 2; # change this to change how many resources are displayed
+                             # before the current resource when using #current
+
+    # If we were passed 'here' information, we are not rendering
+    # after a folder manipulation, and we were not passed an
+    # iterator, make sure we open the folders to show the "here"
+    # marker
+    my $filterHash = {};
+    # Figure out what we're not displaying
+    foreach (split(/\,/, $ENV{"form.filter"})) {
+        if ($_) {
+            $filterHash->{$_} = "1";
+        }
+    }
+
+    # Filter: Remember filter function and add our own filter: Refuse
+    # to show hidden resources unless the user can see them.
+    my $userCanSeeHidden = advancedUser();
+    my $filterFunc = setDefault($args->{'filterFunc'},
+                                sub {return 1;});
+    if (!$userCanSeeHidden) {
+        # Without renaming the filterfunc, the server seems to go into
+        # an infinite loop
+        my $oldFilterFunc = $filterFunc;
+        $filterFunc = sub { my $res = shift; return !$res->randomout() && 
+                                &$oldFilterFunc($res);};
+    }
+
+    my $condition = 0;
+    if ($ENV{'form.condition'}) {
+        $condition = 1;
+    }
+
+    if (!$ENV{'form.folderManip'} && !defined($args->{'iterator'})) {
+        # Step 1: Check to see if we have a navmap
+        if (!defined($navmap)) {
+            $navmap = Apache::lonnavmaps::navmap->new();
+            $mustCloseNavMap = 1;
+        }
+
+        # Step two: Locate what kind of here marker is necessary
+        # Determine where the "here" marker is and where the screen jumps to.
+
+        if ($ENV{'form.postsymb'}) {
+            $here = $jump = $ENV{'form.postsymb'};
+        } elsif ($ENV{'form.postdata'}) {
+            # couldn't find a symb, is there a URL?
+            my $currenturl = $ENV{'form.postdata'};
+            #$currenturl=~s/^http\:\/\///;
+            #$currenturl=~s/^[^\/]+//;
+            
+            $here = $jump = &Apache::lonnet::symbread($currenturl);
+        }
+
+        # Step three: Ensure the folders are open
+        my $mapIterator = $navmap->getIterator(undef, undef, undef, 1);
+        my $curRes;
+        my $found = 0;
+        
+        # We only need to do this if we need to open the maps to show the
+        # current position. This will change the counter so we can't count
+        # for the jump marker with this loop.
+        while (($curRes = $mapIterator->next()) && !$found) {
+            if (ref($curRes) && $curRes->symb() eq $here) {
+                my $mapStack = $mapIterator->getStack();
                 
-                my $colorizer = "";
-                if ($curRes->is_problem()) {
-                    my $status = $curRes->status($part);
-                    my $color = $colormap{$status};
-                    if ($color ne "") {
-                        $colorizer = "bgcolor=\"$color\"";
+                # Ensure the parent maps are open
+                for my $map (@{$mapStack}) {
+                    if ($condition) {
+                        undef $filterHash->{$map->map_pc()};
+                    } else {
+                        $filterHash->{$map->map_pc()} = 1;
                     }
                 }
+                $found = 1;
+            }
+        }            
+    }        
 
-                $r->print("  <tr><td align=\"left\" valign=\"top\">\n");
+    if ( !defined($args->{'iterator'}) && $ENV{'form.folderManip'} ) { # we came from a user's manipulation of the nav page
+        # If this is a click on a folder or something, we want to preserve the "here"
+        # from the querystring, and get the new "jump" marker
+        $here = $ENV{'form.here'};
+        $jump = $ENV{'form.jump'};
+    } 
+    
+    my $it = $args->{'iterator'};
+    if (!defined($it)) {
+        # Construct a default iterator based on $ENV{'form.'} information
+        
+        # Step 1: Check to see if we have a navmap
+        if (!defined($navmap)) {
+            $navmap = Apache::lonnavmaps::navmap->new();
+            $mustCloseNavMap = 1;
+        }
 
-                # print indentation
-                for (my $i = 0; $i < $indentLevel; $i++) {
-                    $r->print($indentString);
-                }
+        # See if we're being passed a specific map
+        if ($args->{'iterator_map'}) {
+            my $map = $args->{'iterator_map'};
+            $map = $navmap->getResourceByUrl($map);
+            my $firstResource = $map->map_start();
+            my $finishResource = $map->map_finish();
 
-                $r->print("  ${newBranchText}${linkopen}<img border=\"0\" src=\"" .
-                          "/adm/lonIcons/$icon\" alt=\"\">${linkclose}\n");
+            $args->{'iterator'} = $it = $navmap->getIterator($firstResource, $finishResource, $filterHash, $condition);
+        } else {
+            $args->{'iterator'} = $it = $navmap->getIterator(undef, undef, $filterHash, $condition);
+        }
+    }
+    
+    # (re-)Locate the jump point, if any
+    # Note this does not take filtering or hidden into account... need
+    # to be fixed?
+    my $mapIterator = $navmap->getIterator(undef, undef, $filterHash, 0);
+    my $curRes;
+    my $foundJump = 0;
+    my $counter = 0;
+    
+    while (($curRes = $mapIterator->next()) && !$foundJump) {
+        if (ref($curRes)) { $counter++; }
+        
+        if (ref($curRes) && $jump eq $curRes->symb()) {
+            
+            # This is why we have to use the main iterator instead of the
+            # potentially faster DFS: The count has to be the same, so
+            # the order has to be the same, which DFS won't give us.
+            $args->{'currentJumpIndex'} = $counter;
+            $foundJump = 1;
+        }
+    }
 
-                if ($curRes->is_problem() && $part != "0") { $partLabel = " (Part $part)"; }
+    my $showParts = setDefault($args->{'showParts'}, 1);
+    my $condenseParts = setDefault($args->{'condenseParts'}, 1);
+    # keeps track of when the current resource is found,
+    # so we can back up a few and put the anchor above the
+    # current resource
+    my $printKey = $args->{'printKey'};
+    my $printCloseAll = $args->{'printCloseAll'};
+    if (!defined($printCloseAll)) { $printCloseAll = 1; }
+    
+    # Print key?
+    if ($printKey) {
+        $result .= '<table border="0" cellpadding="2" cellspacing="0">';
+        my $date=localtime;
+        $result.='<tr><td align="right" valign="bottom">Key:&nbsp;&nbsp;</td>';
+        if ($navmap->{LAST_CHECK}) {
+            $result .= 
+                '<img src="/adm/lonMisc/chat.gif"> '.&mt('New discussion since').' '.
+                strftime("%A, %b %e at %I:%M %P", localtime($navmap->{LAST_CHECK})).
+                '</td><td align="center" valign="bottom">&nbsp;&nbsp;'.
+                '<img src="/adm/lonMisc/feedback.gif"> '.&mt('New message (click to open)').'<p>'.
+                '</td>'; 
+        } else {
+            $result .= '<td align="center" valign="bottom">&nbsp;&nbsp;'.
+                '<img src="/adm/lonMisc/chat.gif"> '.&mt('Discussions').'</td><td align="center" valign="bottom">'.
+                '&nbsp;&nbsp;<img src="/adm/lonMisc/feedback.gif"> '.&mt('New message (click to open)').
+                '</td>'; 
+        }
 
-                $r->print("  <a href=\"$link\">$title$partLabel</a></td>".
-                          "<td $colorizer align=\"right\">\n");
-                
-                if ($curRes->kind() eq "res" and 
-                    $curRes->is_problem() ) {
-                    $r->print (getDescription($curRes, $part));
+        $result .= '</tr></table>';
+    }
+
+    if ($printCloseAll && !$args->{'resource_no_folder_link'}) {
+        if ($condition) {
+            $result.="<a href=\"navmaps?condition=0&filter=&$queryString" .
+                "&here=" . Apache::lonnet::escape($here) .
+                "\">".&mt('Close All Folders')."</a>";
+        } else {
+            $result.="<a href=\"navmaps?condition=1&filter=&$queryString" .
+                "&here=" . Apache::lonnet::escape($here) . 
+                "\">".&mt('Open All Folders')."</a>";
+        }
+        $result .= "<br /><br />\n";
+    }    
+
+    if ($r) {
+        $r->print($result);
+        $r->rflush();
+        $result = "";
+    }
+    # End parameter setting
+            
+    # Data
+    $result .= '<table cellspacing="0" cellpadding="3" border="0" bgcolor="#FFFFFF">' ."\n";
+    my $res = "Apache::lonnavmaps::resource";
+    my %condenseStatuses =
+        ( $res->NETWORK_FAILURE    => 1,
+          $res->NOTHING_SET        => 1,
+          $res->CORRECT            => 1 );
+    my @backgroundColors = ("#FFFFFF", "#F6F6F6");
+
+    # Shared variables
+    $args->{'counter'} = 0; # counts the rows
+    $args->{'indentLevel'} = 0;
+    $args->{'isNewBranch'} = 0;
+    $args->{'condensed'} = 0;    
+    $args->{'indentString'} = setDefault($args->{'indentString'}, "<img src='/adm/lonIcons/whitespace1.gif' width='25' height='1' alt='' border='0' />");
+    $args->{'displayedHereMarker'} = 0;
+
+    # If we're suppressing empty sequences, look for them here. Use DFS for speed,
+    # since structure actually doesn't matter, except what map has what resources.
+    if ($args->{'suppressEmptySequences'}) {
+        my $dfsit = Apache::lonnavmaps::DFSiterator->new($navmap,
+                                                         $it->{FIRST_RESOURCE},
+                                                         $it->{FINISH_RESOURCE},
+                                                         {}, undef, 1);
+        my $depth = 0;
+        $dfsit->next();
+        my $curRes = $dfsit->next();
+        while ($depth > -1) {
+            if ($curRes == $dfsit->BEGIN_MAP()) { $depth++; }
+            if ($curRes == $dfsit->END_MAP()) { $depth--; }
+
+            if (ref($curRes)) { 
+                # Parallel pre-processing: Do sequences have non-filtered-out children?
+                if ($curRes->is_map()) {
+                    $curRes->{DATA}->{HAS_VISIBLE_CHILDREN} = 0;
+                    # Sequences themselves do not count as visible children,
+                    # unless those sequences also have visible children.
+                    # This means if a sequence appears, there's a "promise"
+                    # that there's something under it if you open it, somewhere.
+                } else {
+                    # Not a sequence: if it's filtered, ignore it, otherwise
+                    # rise up the stack and mark the sequences as having children
+                    if (&$filterFunc($curRes)) {
+                        for my $sequence (@{$dfsit->getStack()}) {
+                            $sequence->{DATA}->{HAS_VISIBLE_CHILDREN} = 1;
+                        }
+                    }
                 }
             }
+        } continue {
+            $curRes = $dfsit->next();
         }
-        $curRes = $mapIterator->next();
     }
 
-    $r->print("</table></body></html>");
-
-    return OK;
-}
-
-# Convenience functions: Returns a string that adds or subtracts
-# the second argument from the first hash, appropriate for the 
-# query string that determines which folders to recurse on
-sub addToFilter {
-    my $hashIn = shift;
-    my $addition = shift;
-    my %hash = %$hashIn;
-    $hash{$addition} = 1;
+    my $displayedJumpMarker = 0;
+    # Set up iteration.
+    my $now = time();
+    my $in24Hours = $now + 24 * 60 * 60;
+    my $rownum = 0;
 
-    return join (",", keys(%hash));
-}
+    # export "here" marker information
+    $args->{'here'} = $here;
 
-sub removeFromFilter {
-    my $hashIn = shift;
-    my $subtraction = shift;
-    my %hash = %$hashIn;
+    $args->{'indentLevel'} = -1; # first BEGIN_MAP takes this to 0
+    while ($curRes = $it->next()) {
+        # Maintain indentation level.
+        if ($curRes == $it->BEGIN_MAP() ||
+            $curRes == $it->BEGIN_BRANCH() ) {
+            $args->{'indentLevel'}++;
+        }
+        if ($curRes == $it->END_MAP() ||
+            $curRes == $it->END_BRANCH() ) {
+            $args->{'indentLevel'}--;
+        }
+        # Notice new branches
+        if ($curRes == $it->BEGIN_BRANCH()) {
+            $args->{'isNewBranch'} = 1;
+        }
 
-    delete $hash{$subtraction};
-    return join(",", keys(%hash));
-}
+        # If this isn't an actual resource, continue on
+        if (!ref($curRes)) {
+            next;
+        }
 
-# Convenience function: Given a stack returned from getStack on the iterator,
-# return the correct src() value.
-# Later, this should add an anchor when we start putting anchors in pages.
-sub getLinkForResource {
-    my $stack = shift;
-    my $res;
+        # If this has been filtered out, continue on
+        if (!(&$filterFunc($curRes))) {
+            $args->{'isNewBranch'} = 0; # Don't falsely remember this
+            next;
+        } 
+
+        # If this is an empty sequence and we're filtering them, continue on
+        if ($curRes->is_map() && $args->{'suppressEmptySequences'} &&
+            !$curRes->{DATA}->{HAS_VISIBLE_CHILDREN}) {
+            next;
+        }
 
-    # Check to see if there are any pages in the stack
-    foreach $res (@$stack) {
-        if (defined($res) && $res->is_page()) {
-            return $res->src();
+        # If we're suppressing navmaps and this is a navmap, continue on
+        if ($suppressNavmap && $curRes->src() =~ /^\/adm\/navmaps/) {
+            next;
         }
-    }
 
-    # Failing that, return the src of the last resource that is defined
-    # (when we first recurse on a map, it puts an undefined resource
-    # on the bottom because $self->{HERE} isn't defined yet, and we
-    # want the src for the map anyhow)
-    foreach (@$stack) {
-        if (defined($_)) { $res = $_; }
-    }
+        $args->{'counter'}++;
 
-    return $res->src();
-}
+        # Does it have multiple parts?
+        $args->{'multipart'} = 0;
+        $args->{'condensed'} = 0;
+        my @parts;
+            
+        # Decide what parts to show.
+        if ($curRes->is_problem() && $showParts) {
+            @parts = @{$curRes->parts()};
+            $args->{'multipart'} = $curRes->multipart();
+            
+            if ($condenseParts) { # do the condensation
+                if (!$curRes->opendate("0")) {
+                    @parts = ();
+                    $args->{'condensed'} = 1;
+                }
+                if (!$args->{'condensed'}) {
+                    # Decide whether to condense based on similarity
+                    my $status = $curRes->status($parts[0]);
+                    my $due = $curRes->duedate($parts[0]);
+                    my $open = $curRes->opendate($parts[0]);
+                    my $statusAllSame = 1;
+                    my $dueAllSame = 1;
+                    my $openAllSame = 1;
+                    for (my $i = 1; $i < scalar(@parts); $i++) {
+                        if ($curRes->status($parts[$i]) != $status){
+                            $statusAllSame = 0;
+                        }
+                        if ($curRes->duedate($parts[$i]) != $due ) {
+                            $dueAllSame = 0;
+                        }
+                        if ($curRes->opendate($parts[$i]) != $open) {
+                            $openAllSame = 0;
+                        }
+                    }
+                    # $*allSame is true if all the statuses were
+                    # the same. Now, if they are all the same and
+                    # match one of the statuses to condense, or they
+                    # are all open with the same due date, or they are
+                    # all OPEN_LATER with the same open date, display the
+                    # status of the first non-zero part (to get the 'correct'
+                    # status right, since 0 is never 'correct' or 'open').
+                    if (($statusAllSame && defined($condenseStatuses{$status})) ||
+                        ($dueAllSame && $status == $curRes->OPEN && $statusAllSame)||
+                        ($openAllSame && $status == $curRes->OPEN_LATER && $statusAllSame) ){
+                        @parts = ($parts[0]);
+                        $args->{'condensed'} = 1;
+                    }
+                }
+		# Multipart problem with one part: always "condense" (happens
+		#  to match the desirable behavior)
+		if ($curRes->countParts() == 1) {
+		    @parts = ($parts[0]);
+		    $args->{'condensed'} = 1;
+		}
+            }
+        } 
+            
+        # If the multipart problem was condensed, "forget" it was multipart
+        if (scalar(@parts) == 1) {
+            $args->{'multipart'} = 0;
+        } else {
+            # Add part 0 so we display it correctly.
+            unshift @parts, '0';
+        }
 
-# Convenience function: This seperates the logic of how to create
-# the problem text strings ("Due: DATE", "Open: DATE", "Not yet assigned",
-# etc.) into a seperate function. It takes a resource object as the
-# first parameter, and the part number of the resource as the second.
-# It's basically a big switch statement on the status of the resource.
+        # Now, we've decided what parts to show. Loop through them and
+        # show them.
+        foreach my $part (@parts) {
+            $rownum ++;
+            my $backgroundColor = $backgroundColors[$rownum % scalar(@backgroundColors)];
+            
+            $result .= "  <tr bgcolor='$backgroundColor'>\n";
+
+            # Set up some data about the parts that the cols might want
+            my $filter = $it->{FILTER};
+            my $stack = $it->getStack();
+            my $src = getLinkForResource($stack);
+            
+            my $srcHasQuestion = $src =~ /\?/;
+            $args->{"resourceLink"} = $src.
+                ($srcHasQuestion?'&':'?') .
+                'symb=' . &Apache::lonnet::escape($curRes->symb());
+            
+            # Now, display each column.
+            foreach my $col (@$cols) {
+                my $colHTML = '';
+                if (ref($col)) {
+                    $colHTML .= &$col($curRes, $part, $args);
+                } else {
+                    $colHTML .= &{$preparedColumns[$col]}($curRes, $part, $args);
+                }
 
-sub getDescription {
-    my $res = shift;
-    my $part = shift;
-    my $status = $res->getDateStatus();
+                # If this is the first column and it's time to print
+                # the anchor, do so
+                if ($col == $cols->[0] && 
+                    $args->{'counter'} == $args->{'currentJumpIndex'} - 
+                    $currentJumpDelta) {
+                    # Jam the anchor after the <td> tag;
+                    # necessary for valid HTML (which Mozilla requires)
+                    $colHTML =~ s/\>/\>\<a name="curloc" \/\>/;
+                    $displayedJumpMarker = 1;
+                }
+                $result .= $colHTML . "\n";
+            }
+            $result .= "    </tr>\n";
+            $args->{'isNewBranch'} = 0;
+        }
 
-    if ($status == $res->NETWORK_FAILURE) { return ""; }
-    if ($status == $res->NOTHING_SET) {
-        return "Not currently assigned.";
-    }
-    if ($status == $res->OPEN_LATER) {
-        return "Opens: " . timeToHumanString($res->opendate($part));
-    }
-    if ($status == $res->OPEN) {
-        return "Due: $status " . timeToHumanString($res->duedate($part));
-    }
-    if ($status == $res->PAST_DUE_ANSWER_LATER) {
-        return "Answer: " . timeToHumanString($res->answerdate($part));
+        if ($r && $rownum % 20 == 0) {
+            $r->print($result);
+            $result = "";
+            $r->rflush();
+        }
+    } continue {
+	if ($r) {
+	    # If we have the connection, make sure the user is still connected
+	    my $c = $r->connection;
+	    if ($c->aborted()) {
+		Apache::lonnet::logthis("navmaps aborted");
+		# Who cares what we do, nobody will see it anyhow.
+		return '';
+	    }
+	}
     }
-    if ($status == $res->PAST_DUE_NO_ANSWER) {
-        return "Was Due: " . timeToHumanString($res->duedate($part));
+    
+    # Print out the part that jumps to #curloc if it exists
+    # delay needed because the browser is processing the jump before
+    # it finishes rendering, so it goes to the wrong place!
+    # onload might be better, but this routine has no access to that.
+    # On mozilla, the 0-millisecond timeout seems to prevent this;
+    # it's quite likely this might fix other browsers, too, and 
+    # certainly won't hurt anything.
+    if ($displayedJumpMarker) {
+        $result .= "<script>setTimeout(\"location += '#curloc';\", 0)</script>\n";
     }
-    if ($status == $res->ANSWER_OPEN) {
-        return "Answer available";
+
+    $result .= "</table>";
+    
+    if ($r) {
+        $r->print($result);
+        $result = "";
+        $r->rflush();
     }
-}
+        
+    if ($mustCloseNavMap) { $navmap->untieHashes(); } 
 
-# I want to change this into something more human-friendly. For
-# now, this is a simple call to localtime. The final function
-# probably belongs in loncommon.
-sub timeToHumanString {
-    return localtime(shift);
+    return $result;
 }
 
 1;
 
 package Apache::lonnavmaps::navmap;
 
-# LEFT:
-# * Actual handler code (multi-part)
-# * Branches (aieee!) (and conditionals)
-
 =pod
 
-lonnavmaps provides functions and objects for dealing with the compiled course hashes generated when a user enters the course, and also provides the Apache handler for the "Navigation Map" button.
+=head1 Object: Apache::lonnavmaps::navmap
+
+=head2 Overview
+
+The navmap object's job is to provide access to the resources
+in the course as Apache::lonnavmaps::resource objects, and to
+query and manage the relationship between those resource objects.
+
+Generally, you'll use the navmap object in one of three basic ways.
+In order of increasing complexity and power:
+
+=over 4
+
+=item * C<$navmap-E<gt>getByX>, where X is B<Id>, B<Symb>, B<Url> or B<MapPc>. This provides
+    various ways to obtain resource objects, based on various identifiers.
+    Use this when you want to request information about one object or 
+    a handful of resources you already know the identities of, from some
+    other source. For more about Ids, Symbs, and MapPcs, see the
+    Resource documentation. Note that Url should be a B<last resort>,
+    not your first choice; it only works when there is only one
+    instance of the resource in the course, which only applies to
+    maps, and even that may change in the future.
+
+=item * C<my @resources = $navmap-E<gt>retrieveResources(args)>. This
+    retrieves resources matching some criterion and returns them
+    in a flat array, with no structure information. Use this when
+    you are manipulating a series of resources, based on what map
+    the are in, but do not care about branching, or exactly how
+    the maps and resources are related. This is the most common case.
+
+=item * C<$it = $navmap-E<gt>getIterator(args)>. This allows you traverse
+    the course's navmap in various ways without writing the traversal
+    code yourself. See iterator documentation below. Use this when
+    you need to know absolutely everything about the course, including
+    branches and the precise relationship between maps and resources.
 
-=head1 navmap object: Encapsulating the compiled nav map
+=back
 
-navmap is an object that encapsulates a compiled course map and provides a reasonable interface to it.
+=head2 Creation And Destruction
 
-Most notably it provides a way to navigate the map sensibly and a flexible iterator that makes it easy to write various renderers based on nav maps.
+To create a navmap object, use the following function:
+
+=over 4
 
-You must obtain resource objects through the navmap object.
+=item * B<Apache::lonnavmaps::navmap-E<gt>new>():
+
+Creates a new navmap object. Returns the navmap object if this is
+successful, or B<undef> if not.
+
+=back
+
+When you are done with the $navmap object, you I<must> call 
+$navmap->untieHashes(), or you'll prevent the current user from using that 
+course until the web server is restarted. (!)
 
 =head2 Methods
 
 =over 4
 
-=item * B<new>(filename, parmHashFile, genCourseAndUserOptions, genMailDiscussStatus): Binds a new navmap object to the compiled course representation and parmHashFile. genCourseAndUserOptions is a flag saying whether the course options and user options hash should be generated. This is for when you are using the parameters of the resources that require them; see documentation in resource object documentation. genMailDiscussStatus causes the nav map to retreive information about the email and discussion status of resources. Returns the navmap object if this is successful, or B<undef> if not. You must check for undef; errors will occur when you try to use the other methods otherwise.
+=item * B<getIterator>(first, finish, filter, condition):
 
-=item * B<getIterator>(first, finish, filter, condition): See iterator documentation below.
+See iterator documentation below.
 
 =cut
 
@@ -1113,12 +1697,7 @@ sub new {
     my $class = ref($proto) || $proto;
     my $self = {};
 
-    $self->{NAV_HASH_FILE} = shift;
-    $self->{PARM_HASH_FILE} = shift;
-    $self->{GENERATE_COURSE_USER_OPT} = shift;
-    $self->{GENERATE_EMAIL_DISCUSS_STATUS} = shift;
-
-    # Resource cache stores navmapresource's as we reference them. We generate
+    # Resource cache stores navmap resources as we reference them. We generate
     # them on-demand so we don't pay for creating resources unless we use them.
     $self->{RESOURCE_CACHE} = {};
 
@@ -1127,171 +1706,258 @@ sub new {
     $self->{NETWORK_FAILURE} = 0;
 
     # tie the nav hash
+
     my %navmaphash;
-    if (!(tie(%navmaphash, 'GDBM_File', $self->{NAV_HASH_FILE},
+    my %parmhash;
+    my $courseFn = $ENV{"request.course.fn"};
+    if (!(tie(%navmaphash, 'GDBM_File', "${courseFn}.db",
               &GDBM_READER(), 0640))) {
         return undef;
     }
-    $self->{NAV_HASH} = \%navmaphash;
     
-    my %parmhash;
-    if (!(tie(%parmhash, 'GDBM_File', $self->{PARM_HASH_FILE},
+    if (!(tie(%parmhash, 'GDBM_File', "${courseFn}_parms.db",
               &GDBM_READER(), 0640)))
     {
+        untie %{$self->{PARM_HASH}};
         return undef;
     }
+
+    $self->{NAV_HASH} = \%navmaphash;
     $self->{PARM_HASH} = \%parmhash;
-    $self->{HASH_TIED} = 1;
+    $self->{PARM_CACHE} = {};
 
-    # If the course opt hash and the user opt hash should be generated,
-    # generate them
-    if ($self->{GENERATE_COURSE_USER_OPT}) {
-        my $uname=$ENV{'user.name'};
-        my $udom=$ENV{'user.domain'};
-        my $uhome=$ENV{'user.home'};
-        my $cid=$ENV{'request.course.id'};
-        my $chome=$ENV{'course.'.$cid.'.home'};
-        my ($cdom,$cnum)=split(/\_/,$cid);
-        
-        my $userprefix=$uname.'_'.$udom.'_';
+    bless($self);
         
-        my %courserdatas; my %useropt; my %courseopt;
-        unless ($uhome eq 'no_host') { 
+    return $self;
+}
+
+sub generate_course_user_opt {
+    my $self = shift;
+    if ($self->{COURSE_USER_OPT_GENERATED}) { return; }
+
+    my $uname=$ENV{'user.name'};
+    my $udom=$ENV{'user.domain'};
+    my $uhome=$ENV{'user.home'};
+    my $cid=$ENV{'request.course.id'};
+    my $chome=$ENV{'course.'.$cid.'.home'};
+    my ($cdom,$cnum)=split(/\_/,$cid);
+    
+    my $userprefix=$uname.'_'.$udom.'_';
+    
+    my %courserdatas; my %useropt; my %courseopt; my %userrdatas;
+    unless ($uhome eq 'no_host') { 
 # ------------------------------------------------- Get coursedata (if present)
-            unless ((time-$courserdatas{$cid.'.last_cache'})<240) {
-                my $reply=&Apache::lonnet::reply('dump:'.$cdom.':'.$cnum.
-                                                 ':resourcedata',$chome);
-                if ($reply!~/^error\:/) {
-                    $courserdatas{$cid}=$reply;
-                    $courserdatas{$cid.'.last_cache'}=time;
-                }
-                # check to see if network failed
-                elsif ( $reply=~/no.such.host/i || $reply=~/con.*lost/i )
-                {
-                    $self->{NETWORK_FAILURE} = 1;
-                }
-            }
-            foreach (split(/\&/,$courserdatas{$cid})) {
-                my ($name,$value)=split(/\=/,$_);
-                $courseopt{$userprefix.&Apache::lonnet::unescape($name)}=
-                    &Apache::lonnet::unescape($value);
-            }
+	unless ((time-$courserdatas{$cid.'.last_cache'})<240) {
+	    my $reply=&Apache::lonnet::reply('dump:'.$cdom.':'.$cnum.
+					     ':resourcedata',$chome);
+	    # Check for network failure
+	    if ( $reply =~ /no.such.host/i || $reply =~ /con_lost/i) {
+		$self->{NETWORK_FAILURE} = 1;
+	    } elsif ($reply!~/^error\:/) {
+		$courserdatas{$cid}=$reply;
+		$courserdatas{$cid.'.last_cache'}=time;
+	    }
+	}
+	foreach (split(/\&/,$courserdatas{$cid})) {
+	    my ($name,$value)=split(/\=/,$_);
+	    $courseopt{$userprefix.&Apache::lonnet::unescape($name)}=
+		&Apache::lonnet::unescape($value);
+	}
 # --------------------------------------------------- Get userdata (if present)
-            unless ((time-$userrdatas{$uname.'___'.$udom.'.last_cache'})<240) {
-                my $reply=&Apache::lonnet::reply('dump:'.$udom.':'.$uname.':resourcedata',$uhome);
-                if ($reply!~/^error\:/) {
-                    $userrdatas{$uname.'___'.$udom}=$reply;
-                    $userrdatas{$uname.'___'.$udom.'.last_cache'}=time;
-                }
-                # check to see if network failed
-                elsif ( $reply=~/no.such.host/i || $reply=~/con.*lost/i )
-                {
-                    $self->{NETWORK_FAILURE} = 1;
-                }
-            }
-            foreach (split(/\&/,$userrdatas{$uname.'___'.$udom})) {
-                my ($name,$value)=split(/\=/,$_);
-                $useropt{$userprefix.&Apache::lonnet::unescape($name)}=
-                    &Apache::lonnet::unescape($value);
-            }
-            $self->{COURSE_OPT} = \%courseopt;
-            $self->{USER_OPT} = \%useropt;
-        }
-    }   
+	unless ((time-$userrdatas{$uname.'___'.$udom.'.last_cache'})<240) {
+	    my $reply=&Apache::lonnet::reply('dump:'.$udom.':'.$uname.':resourcedata',$uhome);
+	    if ($reply!~/^error\:/) {
+		$userrdatas{$uname.'___'.$udom}=$reply;
+		$userrdatas{$uname.'___'.$udom.'.last_cache'}=time;
+	    }
+	    # check to see if network failed
+	    elsif ( $reply=~/no.such.host/i || $reply=~/con.*lost/i )
+	    {
+		$self->{NETWORK_FAILURE} = 1;
+	    }
+	}
+	foreach (split(/\&/,$userrdatas{$uname.'___'.$udom})) {
+	    my ($name,$value)=split(/\=/,$_);
+	    $useropt{$userprefix.&Apache::lonnet::unescape($name)}=
+		&Apache::lonnet::unescape($value);
+	}
+	$self->{COURSE_OPT} = \%courseopt;
+	$self->{USER_OPT} = \%useropt;
+    }
 
-    if ($self->{GENERATE_EMAIL_DISCUSS_STATUS}) {
-        my $cid=$ENV{'request.course.id'};
-        my ($cdom,$cnum)=split(/\_/,$cid);
-        
-        my %emailstatus = &Apache::lonnet::dump('email_status');
-        my logoutTime = $emailstatus{'logout'};
-        my courseLeaveTime = $emailstatus{'logout_'.$ENV{'request.course.id'}};
-        $self->{LAST_CHECK} = ($courseLeaveTime > $logoutTime ?
-                               $courseLeaveTime : $logoutTime);
-        my %discussiontime = &Apache::lonnet::dump{'discussiontimes', 
-                                                   $cdom, $cnum);
-        my %feedback=();
-        my %error=();
-        my $keys = &Apache::lonnet::reply('keys:'.
-                                          $ENV{'user.domain'}.':'.
-                                          $ENV{'user.name'}.':nohist_email',
-                                          $ENV{'user.home'});
-
-        foreach my $msgid (split(/\&/, $keys)) {
-            $msgid=&Apache::lonnet::unescape($msgid);
-            my $plain=&Apache::lonnet::unescape(&Apache::lonnet::unescape($msgid));
-            if ($plain=~/(Error|Feedback) \[([^\]]+)\]/) {
-                my ($what,$url)=($1,$2);
-                my %status=
-                    &Apache::lonnet::get('email_status',[$msgid]);
-                if ($status{$msgid}=~/^error\:/) { 
-                    $status{$msgid}=''; 
-                }
-                
-                if (($status{$msgid} eq 'new') || 
-                    (!$status{$msgid})) { 
-                    if ($what eq 'Error') {
-                        $error{$url}.=','.$msgid; 
-                    } else {
-                        $feedback{$url}.=','.$msgid;
-                    }
-                }
-            }
-        }
-        
-        $self->{FEEDBACK} = \%feedback;
-        $self->{ERROR_MSG} = \%error; # what is this? JB
-        $self->{DISCUSSION_TIME} = \%discussiontime;
-        $self->{EMAIL_STATUS} = \%emailstatus;
-        
-    }    
+    $self->{COURSE_USER_OPT_GENERATED} = 1;
     
-    bless($self);
-        
-    return $self;
+    return;
 }
 
+sub generate_email_discuss_status {
+    my $self = shift;
+    if ($self->{EMAIL_DISCUSS_GENERATED}) { return; }
+
+    my $cid=$ENV{'request.course.id'};
+    my ($cdom,$cnum)=split(/\_/,$cid);
+    
+    my %emailstatus = &Apache::lonnet::dump('email_status');
+    my $logoutTime = $emailstatus{'logout'};
+    my $courseLeaveTime = $emailstatus{'logout_'.$ENV{'request.course.id'}};
+    $self->{LAST_CHECK} = (($courseLeaveTime > $logoutTime) ?
+			   $courseLeaveTime : $logoutTime);
+    my %discussiontime = &Apache::lonnet::dump('discussiontimes', 
+					       $cdom, $cnum);
+    my %feedback=();
+    my %error=();
+    my $keys = &Apache::lonnet::reply('keys:'.
+				      $ENV{'user.domain'}.':'.
+				      $ENV{'user.name'}.':nohist_email',
+				      $ENV{'user.home'});
+    
+    foreach my $msgid (split(/\&/, $keys)) {
+	$msgid=&Apache::lonnet::unescape($msgid);
+	my $plain=&Apache::lonnet::unescape(&Apache::lonnet::unescape($msgid));
+	if ($plain=~/(Error|Feedback) \[([^\]]+)\]/) {
+	    my ($what,$url)=($1,$2);
+	    my %status=
+		&Apache::lonnet::get('email_status',[$msgid]);
+	    if ($status{$msgid}=~/^error\:/) { 
+		$status{$msgid}=''; 
+	    }
+	    
+	    if (($status{$msgid} eq 'new') || 
+		(!$status{$msgid})) { 
+		if ($what eq 'Error') {
+		    $error{$url}.=','.$msgid; 
+		} else {
+		    $feedback{$url}.=','.$msgid;
+		}
+	    }
+	}
+    }
+    
+    $self->{FEEDBACK} = \%feedback;
+    $self->{ERROR_MSG} = \%error; # what is this? JB
+    $self->{DISCUSSION_TIME} = \%discussiontime;
+    $self->{EMAIL_STATUS} = \%emailstatus;
+    
+    $self->{EMAIL_DISCUSS_GENERATED} = 1;
+}
+
+sub get_user_data {
+    my $self = shift;
+    if ($self->{RETRIEVED_USER_DATA}) { return; }
+
+    # Retrieve performance data on problems
+    my %student_data = Apache::lonnet::currentdump($ENV{'request.course.id'},
+						   $ENV{'user.domain'},
+						   $ENV{'user.name'});
+    $self->{STUDENT_DATA} = \%student_data;
+
+    $self->{RETRIEVED_USER_DATA} = 1;
+}
+
+# Internal function: Takes a key to look up in the nav hash and implements internal
+# memory caching of that key.
+sub navhash {
+    my $self = shift; my $key = shift;
+    return $self->{NAV_HASH}->{$key};
+}
+
+=pod
+
+=item * B<courseMapDefined>(): Returns true if the course map is defined, 
+    false otherwise. Undefined course maps indicate an error somewhere in
+    LON-CAPA, and you will not be able to proceed with using the navmap.
+    See the B<NAV> screen for an example of using this.
+
+=cut
+
 # Checks to see if coursemap is defined, matching test in old lonnavmaps
 sub courseMapDefined {
     my $self = shift;
     my $uri = &Apache::lonnet::clutter($ENV{'request.course.uri'});
 
-    my $firstres = $self->{NAV_HASH}->{'map_start_$uri'};
-    my $lastres = $self->{NAV_HASH}->{'map_finish_$uri'};
+    my $firstres = $self->navhash("map_start_$uri");
+    my $lastres = $self->navhash("map_finish_$uri");
     return $firstres && $lastres;
 }
 
 sub getIterator {
     my $self = shift;
     my $iterator = Apache::lonnavmaps::iterator->new($self, shift, shift,
-                                                     shift, shift);
+                                                     shift, undef, shift);
     return $iterator;
 }
 
 # unties the hash when done
 sub untieHashes {
     my $self = shift;
-    untie $self->{NAV_HASH} if ($self->{HASH_TIED});
-    untie $self->{PARM_HASH} if ($self->{HASH_TIED});
-    $self->{HASH_TIED} = 0;
+    untie %{$self->{NAV_HASH}};
+    untie %{$self->{PARM_HASH}};
+}
+
+# Private method: Does the given resource (as a symb string) have
+# current discussion? Returns 0 if chat/mail data not extracted.
+sub hasDiscussion {
+    my $self = shift;
+    my $symb = shift;
+    
+    $self->generate_email_discuss_status();
+
+    if (!defined($self->{DISCUSSION_TIME})) { return 0; }
+
+    #return defined($self->{DISCUSSION_TIME}->{$symb});
+    return $self->{DISCUSSION_TIME}->{$symb} >
+           $self->{LAST_CHECK};
+}
+
+# Private method: Does the given resource (as a symb string) have
+# current feedback? Returns the string in the feedback hash, which
+# will be false if it does not exist.
+sub getFeedback { 
+    my $self = shift;
+    my $symb = shift;
+
+    $self->generate_email_discuss_status();
+
+    if (!defined($self->{FEEDBACK})) { return ""; }
+    
+    return $self->{FEEDBACK}->{$symb};
 }
 
-# when the object is destroyed, be sure to untie all the hashes we tied.
-sub DESTROY {
+# Private method: Get the errors for that resource (by source).
+sub getErrors { 
     my $self = shift;
-    $self->untieHashes();
+    my $src = shift;
+
+    $self->generate_email_discuss_status();
+
+    if (!defined($self->{ERROR_MSG})) { return ""; }
+    return $self->{ERROR_MSG}->{$src};
 }
 
 =pod
 
-=item * B<getById>(id): Based on the ID of the resource (1.1, 3.2, etc.), get a resource object for that resource. This method, or other methods that use it (as in the resource object) is the only proper way to obtain a resource object.
+=item * B<getById>(id):
+
+Based on the ID of the resource (1.1, 3.2, etc.), get a resource
+object for that resource. This method, or other methods that use it
+(as in the resource object) is the only proper way to obtain a
+resource object.
+
+=item * B<getBySymb>(symb):
+
+Based on the symb of the resource, get a resource object for that
+resource. This is one of the proper ways to get a resource object.
+
+=item * B<getMapByMapPc>(map_pc):
+
+Based on the map_pc of the resource, get a resource object for
+the given map. This is one of the proper ways to get a resource object.
 
 =cut
 
 # The strategy here is to cache the resource objects, and only construct them
 # as we use them. The real point is to prevent reading any more from the tied
 # hash then we have to, which should hopefully alleviate speed problems.
-# Caching is just an incidental detail I throw in because it makes sense.
 
 sub getById {
     my $self = shift;
@@ -1303,46 +1969,82 @@ sub getById {
     }
 
     # resource handles inserting itself into cache.
-    return Apache::lonnavmaps::resource->new($self, $id);
+    # Not clear why the quotes are necessary, but as of this
+    # writing it doesn't work without them.
+    return "Apache::lonnavmaps::resource"->new($self, $id);
+}
+
+sub getBySymb {
+    my $self = shift;
+    my $symb = shift;
+    my ($mapUrl, $id, $filename) = &Apache::lonnet::decode_symb($symb);
+    my $map = $self->getResourceByUrl($mapUrl);
+    return $self->getById($map->map_pc() . '.' . $id);
+}
+
+sub getByMapPc {
+    my $self = shift;
+    my $map_pc = shift;
+    my $map_id = $self->{NAV_HASH}->{'map_id_' . $map_pc};
+    $map_id = $self->{NAV_HASH}->{'ids_' . $map_id};
+    return $self->getById($map_id);
 }
 
 =pod
 
-=item * B<firstResource>(): Returns a resource object reference corresponding to the first resource in the navmap.
+=item * B<firstResource>():
+
+Returns a resource object reference corresponding to the first
+resource in the navmap.
 
 =cut
 
 sub firstResource {
     my $self = shift;
-    my $firstResource = $self->{NAV_HASH}->{'map_start_' .
-                     &Apache::lonnet::clutter($ENV{'request.course.uri'})};
+    my $firstResource = $self->navhash('map_start_' .
+                     &Apache::lonnet::clutter($ENV{'request.course.uri'}));
     return $self->getById($firstResource);
 }
 
 =pod
 
-=item * B<finishResource>(): Returns a resource object reference corresponding to the last resource in the navmap.
+=item * B<finishResource>():
+
+Returns a resource object reference corresponding to the last resource
+in the navmap.
 
 =cut
 
 sub finishResource {
     my $self = shift;
-    my $firstResource = $self->{NAV_HASH}->{'map_finish_' .
-                     &Apache::lonnet::clutter($ENV{'request.course.uri'})};
+    my $firstResource = $self->navhash('map_finish_' .
+                     &Apache::lonnet::clutter($ENV{'request.course.uri'}));
     return $self->getById($firstResource);
 }
 
-# -------------------------------------------- Figure out a cascading parameter
-#
-# For this function to work
-#
-# * parmhash needs to be tied
-# * courseopt and useropt need to be initialized for this user and course
-#
-
+# Parmval reads the parm hash and cascades the lookups. parmval_real does
+# the actual lookup; parmval caches the results.
 sub parmval {
     my $self = shift;
     my ($what,$symb)=@_;
+    my $hashkey = $what."|||".$symb;
+
+    if (defined($self->{PARM_CACHE}->{$hashkey})) {
+        return $self->{PARM_CACHE}->{$hashkey};
+    }
+
+    my $result = $self->parmval_real($what, $symb);
+    $self->{PARM_CACHE}->{$hashkey} = $result;
+    return $result;
+}
+
+sub parmval_real {
+    my $self = shift;
+    my ($what,$symb,$recurse) = @_;
+
+    # Make sure the {USER_OPT} and {COURSE_OPT} hashes are populated
+    $self->generate_course_user_opt();
+
     my $cid=$ENV{'request.course.id'};
     my $csec=$ENV{'request.course.sec'};
     my $uname=$ENV{'user.name'};
@@ -1351,7 +2053,7 @@ sub parmval {
     unless ($symb) { return ''; }
     my $result='';
 
-    my ($mapname,$id,$fn)=split(/\_\_\_/,$symb);
+    my ($mapname,$id,$fn)=&Apache::lonnet::decode_symb($symb);
 
 # ----------------------------------------------------- Cascading lookup scheme
     my $rwhat=$what;
@@ -1376,69 +2078,193 @@ sub parmval {
 
 # ---------------------------------------------------------- first, check user
     if ($uname and defined($useropt)) {
-        if ($$useropt{$courselevelr}) { return $$useropt{$courselevelr}; }
-        if ($$useropt{$courselevelm}) { return $$useropt{$courselevelm}; }
-        if ($$useropt{$courselevel}) { return $$useropt{$courselevel}; }
+        if (defined($$useropt{$courselevelr})) { return $$useropt{$courselevelr}; }
+        if (defined($$useropt{$courselevelm})) { return $$useropt{$courselevelm}; }
+        if (defined($$useropt{$courselevel})) { return $$useropt{$courselevel}; }
     }
 
 # ------------------------------------------------------- second, check course
     if ($csec and defined($courseopt)) {
-        if ($$courseopt{$seclevelr}) { return $$courseopt{$seclevelr}; }
-        if ($$courseopt{$seclevelm}) { return $$courseopt{$seclevelm}; }
-        if ($$courseopt{$seclevel}) { return $$courseopt{$seclevel}; }
+        if (defined($$courseopt{$seclevelr})) { return $$courseopt{$seclevelr}; }
+        if (defined($$courseopt{$seclevelm})) { return $$courseopt{$seclevelm}; }
+        if (defined($$courseopt{$seclevel})) { return $$courseopt{$seclevel}; }
     }
 
     if (defined($courseopt)) {
-        if ($$courseopt{$courselevelr}) { return $$courseopt{$courselevelr}; }
-        if ($$courseopt{$courselevelm}) { return $$courseopt{$courselevelm}; }
-        if ($$courseopt{$courselevel}) { return $$courseopt{$courselevel}; }
+        if (defined($$courseopt{$courselevelr})) { return $$courseopt{$courselevelr}; }
+        if (defined($$courseopt{$courselevelm})) { return $$courseopt{$courselevelm}; }
+        if (defined($$courseopt{$courselevel})) { return $$courseopt{$courselevel}; }
     }
 
 # ----------------------------------------------------- third, check map parms
 
     my $thisparm=$$parmhash{$symbparm};
-    if ($thisparm) { return $thisparm; }
+    if (defined($thisparm)) { return $thisparm; }
 
 # ----------------------------------------------------- fourth , check default
 
     my $default=&Apache::lonnet::metadata($fn,$rwhat.'.default');
-    if ($default) { return $default}
+    if (defined($default)) { return $default}
 
 # --------------------------------------------------- fifth , cascade up parts
 
     my ($space,@qualifier)=split(/\./,$rwhat);
     my $qualifier=join('.',@qualifier);
     unless ($space eq '0') {
-        my ($part,$id)=split(/\_/,$space);
-        if ($id) {
-            my $partgeneral=$self->parmval($part.".$qualifier",$symb);
-            if ($partgeneral) { return $partgeneral; }
-        } else {
-            my $resourcegeneral=$self->parmval("0.$qualifier",$symb);
-            if ($resourcegeneral) { return $resourcegeneral; }
+	my @parts=split(/_/,$space);
+	my $id=pop(@parts);
+	my $part=join('_',@parts);
+	if ($part eq '') { $part='0'; }
+	my $partgeneral=$self->parmval($part.".$qualifier",$symb,1);
+	if (defined($partgeneral)) { return $partgeneral; }
+    }
+    if ($recurse) { return undef; }
+    my $pack_def=&Apache::lonnet::packages_tab_default($fn,'resource.'.$what);
+    if (defined($pack_def)) { return $pack_def; }
+    return '';
+}
+
+=pod
+
+=item * B<getResourceByUrl>(url):
+
+Retrieves a resource object by URL of the resource. If passed a
+resource object, it will simply return it, so it is safe to use this
+method in code like "$res = $navmap->getResourceByUrl($res)", if
+you're not sure if $res is already an object, or just a URL. If the
+resource appears multiple times in the course, only the first instance
+will be returned. As a result, this is probably useful only for maps.
+
+=item * B<retrieveResources>(map, filterFunc, recursive, bailout):
+
+The map is a specification of a map to retreive the resources from,
+either as a url or as an object. The filterFunc is a reference to a
+function that takes a resource object as its one argument and returns
+true if the resource should be included, or false if it should not
+be. If recursive is true, the map will be recursively examined,
+otherwise it will not be. If bailout is true, the function will return
+as soon as it finds a resource, if false it will finish. By default,
+the map is the top-level map of the course, filterFunc is a function
+that always returns 1, recursive is true, bailout is false. The
+resources will be returned in a list containing the resource objects
+for the corresponding resources, with B<no structure information> in
+the list; regardless of branching, recursion, etc., it will be a flat
+list.
+
+Thus, this is suitable for cases where you don't want the structure,
+just a list of all resources. It is also suitable for finding out how
+many resources match a given description; for this use, if all you
+want to know is if I<any> resources match the description, the bailout
+parameter will allow you to avoid potentially expensive enumeration of
+all matching resources.
+
+=item * B<hasResources>(map, filterFunc, recursive):
+
+Convience method for
+
+ scalar(retrieveResources($map, $filterFunc, $recursive, 1)) > 0
+
+which will tell whether the map has resources matching the description
+in the filter function.
+
+=cut
+
+sub getResourceByUrl {
+    my $self = shift;
+    my $resUrl = shift;
+
+    if (ref($resUrl)) { return $resUrl; }
+
+    $resUrl = &Apache::lonnet::clutter($resUrl);
+    my $resId = $self->{NAV_HASH}->{'ids_' . $resUrl};
+    if ($resId =~ /,/) {
+        $resId = (split (/,/, $resId))[0];
+    }
+    if (!$resId) { return ''; }
+    return $self->getById($resId);
+}
+
+sub retrieveResources {
+    my $self = shift;
+    my $map = shift;
+    my $filterFunc = shift;
+    if (!defined ($filterFunc)) {
+        $filterFunc = sub {return 1;};
+    }
+    my $recursive = shift;
+    if (!defined($recursive)) { $recursive = 1; }
+    my $bailout = shift;
+    if (!defined($bailout)) { $bailout = 0; }
+
+    # Create the necessary iterator.
+    if (!ref($map)) { # assume it's a url of a map.
+        $map = $self->getResourceByUrl($map);
+    }
+
+    # If nothing was passed, assume top-level map
+    if (!$map) {
+	$map = $self->getById('0.0');
+    }
+
+    # Check the map's validity.
+    if (!$map->is_map()) {
+        # Oh, to throw an exception.... how I'd love that!
+        return ();
+    }
+
+    # Get an iterator.
+    my $it = $self->getIterator($map->map_start(), $map->map_finish(),
+                                undef, $recursive);
+
+    my @resources = ();
+
+    # Run down the iterator and collect the resources.
+    my $curRes;
+
+    while ($curRes = $it->next()) {
+        if (ref($curRes)) {
+            if (!&$filterFunc($curRes)) {
+                next;
+            }
+
+            push @resources, $curRes;
+
+            if ($bailout) {
+                return @resources;
+            }
         }
+
     }
-    return '';
+
+    return @resources;
 }
 
+sub hasResource {
+    my $self = shift;
+    my $map = shift;
+    my $filterFunc = shift;
+    my $recursive = shift;
+    
+    return scalar($self->retrieveResources($map, $filterFunc, $recursive, 1)) > 0;
+}
 
 1;
 
 package Apache::lonnavmaps::iterator;
 
-# This package must precede "navmap" because "navmap" uses it. In
-# order to keep the documentation order straight, the iterator is documented
-# after the navmap object.
-
 =pod
 
 =back
 
-=head1 navmap Iterator
-
-An I<iterator> encapsulates the logic required to traverse a data structure. navmap uses an iterator to traverse the course map according to the criteria you wish to use.
+=head1 Object: navmap Iterator
 
-To obtain an iterator, call the B<getIterator>() function of a B<navmap> object. (Do not instantiate Apache::lonnavmaps::iterator directly.) This will return a reference to the iterator:
+An I<iterator> encapsulates the logic required to traverse a data
+structure. navmap uses an iterator to traverse the course map
+according to the criteria you wish to use.
+
+To obtain an iterator, call the B<getIterator>() function of a
+B<navmap> object. (Do not instantiate Apache::lonnavmaps::iterator
+directly.) This will return a reference to the iterator:
 
 C<my $resourceIterator = $navmap-E<gt>getIterator();>
 
@@ -1450,32 +2276,114 @@ getIterator behaves as follows:
 
 =over 4
 
-=item B<getIterator>(nav_map, firstResource, finishResource, filterHash): All parameters are optional. firstResource is a resource reference corresponding to where the iterator should start. It defaults to navmap->firstResource() for the corresponding nav map. finishResource corresponds to where you want the iterator to end, defaulting to navmap->finishResource(). It is your responsibility to ensure that the iterator will actually get there. filterHash is a hash used as a set containing strings representing the resource IDs, defaulting to empty. Condition is a 1 or 0 that sets what to do with the filter hash: If a 1, then only resource that exist IN the filterHash will be recursed on. If it is a 0, only resources NOT in the filterHash will be recursed on. Defaults to 0.
-
-Thus, by default, all resources will be shown. Change the condition to a 1 without changing the hash, and only the top level of the map will be shown. Changing the condition to 1 and including some values in the hash will allow you to selectively examine parts of the navmap, while leaving it on 0 and adding things to the hash will allow you to selectively ignore parts of the nav map. See the handler code for examples.
+=item * B<getIterator>(firstResource, finishResource, filterHash, condition, forceTop, returnTopMap):
 
-The iterator will return either a reference to a resource object, or a token representing something in the map, such as the beginning of a new branch. The possible tokens are:
+All parameters are optional. firstResource is a resource reference
+corresponding to where the iterator should start. It defaults to
+navmap->firstResource() for the corresponding nav map. finishResource
+corresponds to where you want the iterator to end, defaulting to
+navmap->finishResource(). filterHash is a hash used as a set
+containing strings representing the resource IDs, defaulting to
+empty. Condition is a 1 or 0 that sets what to do with the filter
+hash: If a 0, then only resources that exist IN the filterHash will be
+recursed on. If it is a 1, only resources NOT in the filterHash will
+be recursed on. Defaults to 0. forceTop is a boolean value. If it is
+false (default), the iterator will only return the first level of map
+that is not just a single, 'redirecting' map. If true, the iterator
+will return all information, starting with the top-level map,
+regardless of content. returnTopMap, if true (default false), will
+cause the iterator to return the top-level map object (resource 0.0)
+before anything else.
+
+Thus, by default, only top-level resources will be shown. Change the
+condition to a 1 without changing the hash, and all resources will be
+shown. Changing the condition to 1 and including some values in the
+hash will allow you to selectively suppress parts of the navmap, while
+leaving it on 0 and adding things to the hash will allow you to
+selectively add parts of the nav map. See the handler code for
+examples.
+
+The iterator will return either a reference to a resource object, or a
+token representing something in the map, such as the beginning of a
+new branch. The possible tokens are:
 
 =over 4
 
-=item * some list of tokens here
+=item * B<END_ITERATOR>:
+
+The iterator has returned all that it's going to. Further calls to the
+iterator will just produce more of these. This is a "false" value, and
+is the only false value the iterator which will be returned, so it can
+be used as a loop sentinel.
+
+=item * B<BEGIN_MAP>:
+
+A new map is being recursed into. This is returned I<after> the map
+resource itself is returned.
+
+=item * B<END_MAP>:
+
+The map is now done.
+
+=item * B<BEGIN_BRANCH>:
+
+A branch is now starting. The next resource returned will be the first
+in that branch.
+
+=item * B<END_BRANCH>:
+
+The branch is now done.
 
 =back
 
-The tokens are retreivable via methods on the iterator object, i.e., $iterator->END_NAV_MAP. (Perl will automatically optimize these into constants.
+The tokens are retreivable via methods on the iterator object, i.e.,
+$iterator->END_MAP.
+
+Maps can contain empty resources. The iterator will automatically skip
+over such resources, but will still treat the structure
+correctly. Thus, a complicated map with several branches, but
+consisting entirely of empty resources except for one beginning or
+ending resource, will cause a lot of BRANCH_STARTs and BRANCH_ENDs,
+but only one resource will be returned.
+
+=head2 Normal Usage
+
+Normal usage of the iterator object is to do the following:
+
+ my $it = $navmap->getIterator([your params here]);
+ my $curRes;
+ while ($curRes = $it->next()) {
+   [your logic here]
+ }
+
+Note that inside of the loop, it's frequently useful to check if
+"$curRes" is a reference or not with the reference function; only
+resource objects will be references, and any non-references will 
+be the tokens described above.
+
+Also note there is some old code floating around that trys to track
+the depth of the iterator to see when it's done; do not copy that 
+code. It is difficult to get right and harder to understand then
+this. They should be migrated to this new style.
+
+=back
 
 =cut
 
 # Here are the tokens for the iterator:
 
-sub END_NAV_MAP { return 0; }  # Represents end of entire nav map
+sub END_ITERATOR { return 0; }
 sub BEGIN_MAP { return 1; }    # begining of a new map
 sub END_MAP { return 2; }      # end of the map
 sub BEGIN_BRANCH { return 3; } # beginning of a branch
 sub END_BRANCH { return 4; }   # end of a branch
+sub FORWARD { return 1; }      # go forward
+sub BACKWARD { return 2; }
 
-# Params: nav map, start resource, end resource, filter, condition, 
-# already seen hash ref
+sub min {
+    (my $a, my $b) = @_;
+    if ($a < $b) { return $a; } else { return $b; }
+}
 
 sub new {
     # magic invocation to create a class instance
@@ -1502,8 +2410,373 @@ sub new {
     # A hash, used as a set, of resource already seen
     $self->{ALREADY_SEEN} = shift;
     if (!defined($self->{ALREADY_SEEN})) { $self->{ALREADY_SEEN} = {} };
+    $self->{CONDITION} = shift;
 
-    # Flag: Have we started yet? If not, the first action is to return BEGIN_MAP.
+    # Do we want to automatically follow "redirection" maps?
+    $self->{FORCE_TOP} = shift;
+
+    # Do we want to return the top-level map object (resource 0.0)?
+    $self->{RETURN_0} = shift;
+    # have we done that yet?
+    $self->{HAVE_RETURNED_0} = 0;
+
+    # Now, we need to pre-process the map, by walking forward and backward
+    # over the parts of the map we're going to look at.
+
+    # The processing steps are exactly the same, except for a few small 
+    # changes, so I bundle those up in the following list of two elements:
+    # (direction_to_iterate, VAL_name, next_resource_method_to_call,
+    # first_resource).
+    # This prevents writing nearly-identical code twice.
+    my @iterations = ( [FORWARD(), 'TOP_DOWN_VAL', 'getNext', 
+                        'FIRST_RESOURCE'],
+                       [BACKWARD(), 'BOT_UP_VAL', 'getPrevious', 
+                        'FINISH_RESOURCE'] );
+
+    my $maxDepth = 0; # tracks max depth
+
+    # If there is only one resource in this map, and it's a map, we
+    # want to remember that, so the user can ask for the first map
+    # that isn't just a redirector.
+    my $resource; my $resourceCount = 0;
+
+    # Documentation on this algorithm can be found in the CVS repository at 
+    # /docs/lonnavdocs; these "**#**" markers correspond to documentation
+    # in that file.
+    # **1**
+
+    foreach my $pass (@iterations) {
+        my $direction = $pass->[0];
+        my $valName = $pass->[1];
+        my $nextResourceMethod = $pass->[2];
+        my $firstResourceName = $pass->[3];
+
+        my $iterator = Apache::lonnavmaps::DFSiterator->new($self->{NAV_MAP}, 
+                                                            $self->{FIRST_RESOURCE},
+                                                            $self->{FINISH_RESOURCE},
+                                                            {}, undef, 0, $direction);
+    
+        # prime the recursion
+        $self->{$firstResourceName}->{DATA}->{$valName} = 0;
+	$iterator->next();
+        my $curRes = $iterator->next();
+	my $depth = 1;
+        while ($depth > 0) {
+	    if ($curRes == $iterator->BEGIN_MAP()) { $depth++; }
+	    if ($curRes == $iterator->END_MAP()) { $depth--; }
+
+            if (ref($curRes)) {
+                # If there's only one resource, this will save it
+                # we have to filter empty resources from consideration here,
+                # or even "empty", redirecting maps have two (start & finish)
+                # or three (start, finish, plus redirector)
+                if($direction == FORWARD && $curRes->src()) { 
+                    $resource = $curRes; $resourceCount++; 
+                }
+                my $resultingVal = $curRes->{DATA}->{$valName};
+                my $nextResources = $curRes->$nextResourceMethod();
+                my $nextCount = scalar(@{$nextResources});
+
+                if ($nextCount == 1) { # **3**
+                    my $current = $nextResources->[0]->{DATA}->{$valName} || 999999999;
+                    $nextResources->[0]->{DATA}->{$valName} = min($resultingVal, $current);
+                }
+                
+                if ($nextCount > 1) { # **4**
+                    foreach my $res (@{$nextResources}) {
+                        my $current = $res->{DATA}->{$valName} || 999999999;
+                        $res->{DATA}->{$valName} = min($current, $resultingVal + 1);
+                    }
+                }
+            }
+            
+            # Assign the final val (**2**)
+            if (ref($curRes) && $direction == BACKWARD()) {
+                my $finalDepth = min($curRes->{DATA}->{TOP_DOWN_VAL},
+                                     $curRes->{DATA}->{BOT_UP_VAL});
+                
+                $curRes->{DATA}->{DISPLAY_DEPTH} = $finalDepth;
+                if ($finalDepth > $maxDepth) {$maxDepth = $finalDepth;}
+            }
+
+	    $curRes = $iterator->next();
+        }
+    }
+
+    # Check: Was this only one resource, a map?
+    if ($resourceCount == 1 && $resource->is_map() && !$self->{FORCE_TOP}) { 
+        my $firstResource = $resource->map_start();
+        my $finishResource = $resource->map_finish();
+        return 
+            Apache::lonnavmaps::iterator->new($self->{NAV_MAP}, $firstResource,
+                                              $finishResource, $self->{FILTER},
+                                              $self->{ALREADY_SEEN}, 
+                                              $self->{CONDITION}, 0);
+        
+    }
+
+    # Set up some bookkeeping information.
+    $self->{CURRENT_DEPTH} = 0;
+    $self->{MAX_DEPTH} = $maxDepth;
+    $self->{STACK} = [];
+    $self->{RECURSIVE_ITERATOR_FLAG} = 0;
+    $self->{FINISHED} = 0; # When true, the iterator has finished
+
+    for (my $i = 0; $i <= $self->{MAX_DEPTH}; $i++) {
+        push @{$self->{STACK}}, [];
+    }
+
+    # Prime the recursion w/ the first resource **5**
+    push @{$self->{STACK}->[0]}, $self->{FIRST_RESOURCE};
+    $self->{ALREADY_SEEN}->{$self->{FIRST_RESOURCE}->{ID}} = 1;
+
+    bless ($self);
+
+    return $self;
+}
+
+sub next {
+    my $self = shift;
+
+    if ($self->{FINISHED}) {
+	return END_ITERATOR();
+    }
+
+    # If we want to return the top-level map object, and haven't yet,
+    # do so.
+    if ($self->{RETURN_0} && !$self->{HAVE_RETURNED_0}) {
+        $self->{HAVE_RETURNED_0} = 1;
+        return $self->{NAV_MAP}->getById('0.0');
+    }
+
+    if ($self->{RECURSIVE_ITERATOR_FLAG}) {
+        # grab the next from the recursive iterator 
+        my $next = $self->{RECURSIVE_ITERATOR}->next();
+
+        # is it a begin or end map? If so, update the depth
+        if ($next == BEGIN_MAP() ) { $self->{RECURSIVE_DEPTH}++; }
+        if ($next == END_MAP() ) { $self->{RECURSIVE_DEPTH}--; }
+
+        # Are we back at depth 0? If so, stop recursing
+        if ($self->{RECURSIVE_DEPTH} == 0) {
+            $self->{RECURSIVE_ITERATOR_FLAG} = 0;
+        }
+
+        return $next;
+    }
+
+    if (defined($self->{FORCE_NEXT})) {
+        my $tmp = $self->{FORCE_NEXT};
+        $self->{FORCE_NEXT} = undef;
+        return $tmp;
+    }
+
+    # Have we not yet begun? If not, return BEGIN_MAP and
+    # remember we've started.
+    if ( !$self->{STARTED} ) { 
+        $self->{STARTED} = 1;
+        return $self->BEGIN_MAP();
+    }
+
+    # Here's the guts of the iterator.
+    
+    # Find the next resource, if any.
+    my $found = 0;
+    my $i = $self->{MAX_DEPTH};
+    my $newDepth;
+    my $here;
+    while ( $i >= 0 && !$found ) {
+        if ( scalar(@{$self->{STACK}->[$i]}) > 0 ) { # **6**
+            $here = pop @{$self->{STACK}->[$i]}; # **7**
+            $found = 1;
+            $newDepth = $i;
+        }
+        $i--;
+    }
+
+    # If we still didn't find anything, we're done.
+    if ( !$found ) {
+        # We need to get back down to the correct branch depth
+        if ( $self->{CURRENT_DEPTH} > 0 ) {
+            $self->{CURRENT_DEPTH}--;
+            return END_BRANCH();
+        } else {
+	    $self->{FINISHED} = 1;
+            return END_MAP();
+        }
+    }
+
+    # If this is not a resource, it must be an END_BRANCH marker we want
+    # to return directly.
+    if (!ref($here)) { # **8**
+        if ($here == END_BRANCH()) { # paranoia, in case of later extension
+            $self->{CURRENT_DEPTH}--;
+            return $here;
+        }
+    }
+
+    # Otherwise, it is a resource and it's safe to store in $self->{HERE}
+    $self->{HERE} = $here;
+
+    # Get to the right level
+    if ( $self->{CURRENT_DEPTH} > $newDepth ) {
+        push @{$self->{STACK}->[$newDepth]}, $here;
+        $self->{CURRENT_DEPTH}--;
+        return END_BRANCH();
+    }
+    if ( $self->{CURRENT_DEPTH} < $newDepth) {
+        push @{$self->{STACK}->[$newDepth]}, $here;
+        $self->{CURRENT_DEPTH}++;
+        return BEGIN_BRANCH();
+    }
+
+    # If we made it here, we have the next resource, and we're at the
+    # right branch level. So let's examine the resource for where
+    # we can get to from here.
+
+    # So we need to look at all the resources we can get to from here,
+    # categorize them if we haven't seen them, remember if we have a new
+    my $nextUnfiltered = $here->getNext();
+    my $maxDepthAdded = -1;
+    
+    for (@$nextUnfiltered) {
+        if (!defined($self->{ALREADY_SEEN}->{$_->{ID}})) {
+            my $depth = $_->{DATA}->{DISPLAY_DEPTH};
+            push @{$self->{STACK}->[$depth]}, $_;
+            $self->{ALREADY_SEEN}->{$_->{ID}} = 1;
+            if ($maxDepthAdded < $depth) { $maxDepthAdded = $depth; }
+        }
+    }
+
+    # Is this the end of a branch? If so, all of the resources examined above
+    # led to lower levels then the one we are currently at, so we push a END_BRANCH
+    # marker onto the stack so we don't forget.
+    # Example: For the usual A(BC)(DE)F case, when the iterator goes down the
+    # BC branch and gets to C, it will see F as the only next resource, but it's
+    # one level lower. Thus, this is the end of the branch, since there are no
+    # more resources added to this level or above.
+    # We don't do this if the examined resource is the finish resource,
+    # because the condition given above is true, but the "END_MAP" will
+    # take care of things and we should already be at depth 0.
+    my $isEndOfBranch = $maxDepthAdded < $self->{CURRENT_DEPTH};
+    if ($isEndOfBranch && $here != $self->{FINISH_RESOURCE}) { # **9**
+        push @{$self->{STACK}->[$self->{CURRENT_DEPTH}]}, END_BRANCH();
+    }
+
+    # That ends the main iterator logic. Now, do we want to recurse
+    # down this map (if this resource is a map)?
+    if ($self->{HERE}->is_map() &&
+        (defined($self->{FILTER}->{$self->{HERE}->map_pc()}) xor $self->{CONDITION})) {
+        $self->{RECURSIVE_ITERATOR_FLAG} = 1;
+        my $firstResource = $self->{HERE}->map_start();
+        my $finishResource = $self->{HERE}->map_finish();
+
+        $self->{RECURSIVE_ITERATOR} = 
+            Apache::lonnavmaps::iterator->new($self->{NAV_MAP}, $firstResource,
+                                              $finishResource, $self->{FILTER},
+                                              $self->{ALREADY_SEEN}, $self->{CONDITION});
+    }
+
+    # If this is a blank resource, don't actually return it.
+    # Should you ever find you need it, make sure to add an option to the code
+    #  that you can use; other things depend on this behavior.
+    my $browsePriv = $self->{HERE}->browsePriv();
+    if (!$self->{HERE}->src() || 
+        (!($browsePriv eq 'F') && !($browsePriv eq '2')) ) {
+        return $self->next();
+    }
+
+    return $self->{HERE};
+
+}
+
+=pod
+
+The other method available on the iterator is B<getStack>, which
+returns an array populated with the current 'stack' of maps, as
+references to the resource objects. Example: This is useful when
+making the navigation map, as we need to check whether we are under a
+page map to see if we need to link directly to the resource, or to the
+page. The first elements in the array will correspond to the top of
+the stack (most inclusive map).
+
+=cut
+
+sub getStack {
+    my $self=shift;
+
+    my @stack;
+
+    $self->populateStack(\@stack);
+
+    return \@stack;
+}
+
+# Private method: Calls the iterators recursively to populate the stack.
+sub populateStack {
+    my $self=shift;
+    my $stack = shift;
+
+    push @$stack, $self->{HERE} if ($self->{HERE});
+
+    if ($self->{RECURSIVE_ITERATOR_FLAG}) {
+        $self->{RECURSIVE_ITERATOR}->populateStack($stack);
+    }
+}
+
+1;
+
+package Apache::lonnavmaps::DFSiterator;
+
+# Not documented in the perldoc: This is a simple iterator that just walks
+#  through the nav map and presents the resources in a depth-first search
+#  fashion, ignorant of conditionals, randomized resources, etc. It presents
+#  BEGIN_MAP and END_MAP, but does not understand branches at all. It is
+#  useful for pre-processing of some kind, and is in fact used by the main
+#  iterator that way, but that's about it.
+# One could imagine merging this into the init routine of the main iterator,
+#  but this might as well be left seperate, since it is possible some other
+#  use might be found for it. - Jeremy
+
+# Unlike the main iterator, this DOES return all resources, even blank ones.
+#  The main iterator needs them to correctly preprocess the map.
+
+sub BEGIN_MAP { return 1; }    # begining of a new map
+sub END_MAP { return 2; }      # end of the map
+sub FORWARD { return 1; }      # go forward
+sub BACKWARD { return 2; }
+
+# Params: Nav map ref, first resource id/ref, finish resource id/ref,
+#         filter hash ref (or undef), already seen hash or undef, condition
+#         (as in main iterator), direction FORWARD or BACKWARD (undef->forward).
+sub new {
+    # magic invocation to create a class instance
+    my $proto = shift;
+    my $class = ref($proto) || $proto;
+    my $self = {};
+
+    $self->{NAV_MAP} = shift;
+    return undef unless ($self->{NAV_MAP});
+
+    $self->{FIRST_RESOURCE} = shift || $self->{NAV_MAP}->firstResource();
+    $self->{FINISH_RESOURCE} = shift || $self->{NAV_MAP}->finishResource();
+
+    # If the given resources are just the ID of the resource, get the
+    # objects
+    if (!ref($self->{FIRST_RESOURCE})) { $self->{FIRST_RESOURCE} = 
+             $self->{NAV_MAP}->getById($self->{FIRST_RESOURCE}); }
+    if (!ref($self->{FINISH_RESOURCE})) { $self->{FINISH_RESOURCE} = 
+             $self->{NAV_MAP}->getById($self->{FINISH_RESOURCE}); }
+
+    $self->{FILTER} = shift;
+
+    # A hash, used as a set, of resource already seen
+    $self->{ALREADY_SEEN} = shift;
+     if (!defined($self->{ALREADY_SEEN})) { $self->{ALREADY_SEEN} = {} };
+    $self->{CONDITION} = shift;
+    $self->{DIRECTION} = shift || FORWARD();
+
+    # Flag: Have we started yet?
     $self->{STARTED} = 0;
 
     # Should we continue calling the recursive iterator, if any?
@@ -1517,41 +2790,25 @@ sub new {
     $self->{RECURSIVE_DEPTH} = 0;
 
     # For keeping track of our branches, we maintain our own stack
-    $self->{BRANCH_STACK} = [];
-    # If the size shrinks, we exhausted a branch
-    $self->{BRANCH_STACK_SIZE} = 0;
-    $self->{BRANCH_DEPTH} = 0;
-
-    # For returning two things in a forced sequence
-    $self->{FORCE_NEXT} = undef;
+    $self->{STACK} = [];
 
     # Start with the first resource
-    push @{$self->{BRANCH_STACK}}, $self->{FIRST_RESOURCE};
-    $self->{BRANCH_STACK_SIZE} = 1;
+    if ($self->{DIRECTION} == FORWARD) {
+        push @{$self->{STACK}}, $self->{FIRST_RESOURCE};
+    } else {
+        push @{$self->{STACK}}, $self->{FINISH_RESOURCE};
+    }
 
     bless($self);
     return $self;
 }
 
-# Note... this function is *touchy*. I strongly recommend tracing
-# through it with the debugger a few times on a non-trivial map before
-# modifying it. Order is *everything*.
 sub next {
     my $self = shift;
     
-    # Iterator logic goes here
-
-    # Is this return value pre-determined?
-    if (defined($self->{FORCE_NEXT})) {
-        my $tmp = $self->{FORCE_NEXT};
-        $self->{FORCE_NEXT} = undef;
-        return $tmp;
-    }
-
     # Are we using a recursive iterator? If so, pull from that and
     # watch the depth; we want to resume our level at the correct time.
-    if ($self->{RECURSIVE_ITERATOR_FLAG})
-    {
+    if ($self->{RECURSIVE_ITERATOR_FLAG}) {
         # grab the next from the recursive iterator
         my $next = $self->{RECURSIVE_ITERATOR}->next();
         
@@ -1568,15 +2825,9 @@ sub next {
     }
 
     # Is there a current resource to grab? If not, then return
-    # END_BRANCH and END_MAP in succession.
-    if (scalar(@{$self->{BRANCH_STACK}}) == 0) {
-        if ($self->{BRANCH_DEPTH} > 0) {
-            $self->{FORCE_NEXT} = $self->END_MAP();
-            $self->{BRANCH_DEPTH}--;
-            return $self->END_BRANCH();
-        } else {
-            return $self->END_MAP();
-        }
+    # END_MAP, which will end the iterator.
+    if (scalar(@{$self->{STACK}}) == 0) {
+        return $self->END_MAP();
     }
 
     # Have we not yet begun? If not, return BEGIN_MAP and 
@@ -1586,115 +2837,52 @@ sub next {
         return $self->BEGIN_MAP;
     }
 
-    # Did the branch stack shrink since last run? If so,
-    # we exhausted a branch last time, therefore, we're about
-    # to start a new one. (We know because we already checked to see
-    # if the stack was empty.)
-    if ( scalar (@{$self->{BRANCH_STACK}}) < $self->{BRANCH_STACK_SIZE}) {
-        $self->{BRANCH_STACK_SIZE} = scalar(@{$self->{BRANCH_STACK}});
-        $self->{BRANCH_DEPTH}++;
-        return $self->BEGIN_BRANCH();
-    }
-
-    # Remember the size for comparision next time.
-    $self->{BRANCH_STACK_SIZE} = scalar(@{$self->{BRANCH_STACK}});
-
-    # If the next resource we mean to return is going to need
-    # a lower branch level, terminate branches until we get 
-    # there.
-
     # Get the next resource in the branch
-    $self->{HERE} = pop @{$self->{BRANCH_STACK}};
+    $self->{HERE} = pop @{$self->{STACK}};
 
-    # Are we at the right depth? If not, close a branch and return
-    # the current resource onto the branch stack
-    if (defined($self->{HERE}->{DATA}->{ITERATOR_DEPTH})
-        && $self->{HERE}->{DATA}->{ITERATOR_DEPTH} <
-        $self->{BRANCH_DEPTH} ) {
-        $self->{BRANCH_DEPTH}--;
-        # return it so we can pick it up eventually
-        push @{$self->{BRANCH_STACK}}, $self->{HERE};
-        return $self->END_BRANCH();
-    }
-
-    # We always return it after this point and never before
-    # (proof: look at just the return statements), so we
-    # remember that we've seen this.
+    # remember that we've seen this, so we don't return it again later
     $self->{ALREADY_SEEN}->{$self->{HERE}->{ID}} = 1;
     
-    # Are we at the utter end? If so, return the END_NAV_MAP marker.
-    if ($self->{HERE} == $self->{NAV_MAP}->finishResource() ) {
-        $self->{FORCE_NEXT} = $self->END_NAV_MAP;
-        return $self->{HERE};
-    }
-    
     # Get the next possible resources
-    my $nextUnfiltered = $self->{HERE}->getNext();
+    my $nextUnfiltered;
+    if ($self->{DIRECTION} == FORWARD()) {
+        $nextUnfiltered = $self->{HERE}->getNext();
+    } else {
+        $nextUnfiltered = $self->{HERE}->getPrevious();
+    }
     my $next = [];
 
     # filter the next possibilities to remove things we've 
-    # already seen. Also, remember what branch depth they should
-    # be displayed at, since there's no other reliable way to tell.
+    # already seen.
     foreach (@$nextUnfiltered) {
         if (!defined($self->{ALREADY_SEEN}->{$_->{ID}})) {
             push @$next, $_;
-            $_->{DATA}->{ITERATOR_DEPTH} = 
-                $self->{BRANCH_DEPTH} + 1;
         }
     }
 
-    # Handle branch cases:
-    # Nothing is available next: BRANCH_END
-    # 1 thing next: standard non-branch
-    # 2+ things next: have some branches
-    my $nextCount = scalar(@$next);
-    if ($nextCount == 0) {
-        # Return this and on the next run, close the branch up if we're 
-        # in a branch
-        if ($self->{BRANCH_DEPTH} > 0 ) {
-            $self->{FORCE_NEXT} = $self->END_BRANCH();
-            $self->{BRANCH_DEPTH}--;
-        }
-        return $self->{HERE};
-    }
-    
     while (@$next) {
-        # copy the next possibilities over to the branch stack
-        # in the right order
-        push @{$self->{BRANCH_STACK}}, shift @$next;
-    }
-
-    if ($nextCount >= 2) {
-        $self->{FORCE_NEXT} = $self->BEGIN_BRANCH();
-        $self->{BRANCH_DEPTH}++;
-        return $self->{HERE}; 
+        # copy the next possibilities over to the stack
+        push @{$self->{STACK}}, shift @$next;
     }
 
     # If this is a map and we want to recurse down it... (not filtered out)
     if ($self->{HERE}->is_map() && 
-         !defined($self->{FILTER}->{$self->{HERE}->map_pc()})) { 
+         (defined($self->{FILTER}->{$self->{HERE}->map_pc()}) xor $self->{CONDITION})) { 
         $self->{RECURSIVE_ITERATOR_FLAG} = 1;
         my $firstResource = $self->{HERE}->map_start();
         my $finishResource = $self->{HERE}->map_finish();
 
-        # Odd perl syntax here; $self->new allows one to create a new iterator
-        # can't figure out how to ref this package directly correctly
-        # isn't MAIN::new, __PACKAGE__::new or Apache::lonnavmaps::iterator->new
         $self->{RECURSIVE_ITERATOR} =
-          Apache::lonnavmaps::iterator->new ($self->{NAV_MAP}, $firstResource, 
-                     $finishResource, $self->{FILTER}, $self->{ALREADY_SEEN});
-        # prime the new iterator with the first resource
-        #push @{$self->{RECURSIVE_ITERATOR}->{BRANCH_STACK}}, $firstResource;
+          Apache::lonnavmaps::DFSiterator->new ($self->{NAV_MAP}, $firstResource, 
+                     $finishResource, $self->{FILTER}, $self->{ALREADY_SEEN},
+                                             $self->{CONDITION}, $self->{DIRECTION});
     }
 
     return $self->{HERE};
 }
 
-=pod
-
-The other method available on the iterator is B<getStack>, which returns an array populated with the current 'stack' of maps, as references to the resource objects. Example: This is useful when making the navigation map, as we need to check whether we are under a page map to see if we need to link directly to the resource, or to the page. The first elements in the array will correspond to the top of the stack (most inclusive map).
-
-=cut
+# Identical to the full iterator methods of the same name. Hate to copy/paste
+# but I also hate to "inherit" either iterator from the other.
 
 sub getStack {
     my $self=shift;
@@ -1711,7 +2899,7 @@ sub populateStack {
     my $self=shift;
     my $stack = shift;
 
-    push @$stack, $self->{HERE};
+    push @$stack, $self->{HERE} if ($self->{HERE});
 
     if ($self->{RECURSIVE_ITERATOR_FLAG}) {
         $self->{RECURSIVE_ITERATOR}->populateStack($stack);
@@ -1726,23 +2914,74 @@ use Apache::lonnet;
 
 =pod
 
-=head1 Object: resource
-
-A resource object encapsulates a resource in a resource map, allowing easy manipulation of the resource, querying the properties of the resource (including user properties), and represents a reference that can be used as the canonical representation of the resource by lonnavmap clients like renderers.
-
-A resource only makes sense in the context of a navmap, as some of the data is stored in the navmap object.
-
-You will probably never need to instantiate this object directly. Use Apache::lonnavmap::navmap, and use the "start" method to obtain the starting resource.
-
-=head2 Public Members
-
-resource objects have a hash called DATA ($resourceRef->{DATA}) that you can store whatever you want in. This allows you to easily do two-pass algorithms without worrying about managing your own resource->data hash.
-
-=head2 Methods
-
-=over 4
+=head1 Object: resource 
 
-=item * B<new>($navmapRef, $idString): The first arg is a reference to the parent navmap object. The second is the idString of the resource itself. 
+X<resource, navmap object>
+A resource object encapsulates a resource in a resource map, allowing
+easy manipulation of the resource, querying the properties of the
+resource (including user properties), and represents a reference that
+can be used as the canonical representation of the resource by
+lonnavmap clients like renderers.
+
+A resource only makes sense in the context of a navmap, as some of the
+data is stored in the navmap object.
+
+You will probably never need to instantiate this object directly. Use
+Apache::lonnavmaps::navmap, and use the "start" method to obtain the
+starting resource.
+
+Resource objects respect the parameter_hiddenparts, which suppresses 
+various parts according to the wishes of the map author. As of this
+writing, there is no way to override this parameter, and suppressed
+parts will never be returned, nor will their response types or ids be
+stored.
+
+=head2 Overview
+
+A B<Resource> is the most granular type of object in LON-CAPA that can
+be included in a course. It can either be a particular resource, like
+an HTML page, external resource, problem, etc., or it can be a
+container sequence, such as a "page" or a "map".
+
+To see a sequence from the user's point of view, please see the
+B<Creating a Course: Maps and Sequences> chapter of the Author's
+Manual.
+
+A Resource Object, once obtained from a navmap object via a B<getBy*>
+method of the navmap, or from an iterator, allows you to query
+information about that resource.
+
+Generally, you do not ever want to create a resource object yourself,
+so creation has been left undocumented. Always retrieve resources
+from navmap objects.
+
+=head3 Identifying Resources
+
+X<big hash>Every resource is identified by a Resource ID in the big hash that is
+unique to that resource for a given course. X<resource ID, in big hash>
+The Resource ID has the form #.#, where the first number is the same
+for every resource in a map, and the second is unique. For instance,
+for a course laid out like this:
+
+ * Problem 1
+ * Map
+   * Resource 2
+   * Resource 3
+
+C<Problem 1> and C<Map> will share a first number, and C<Resource 2>
+C<Resource 3> will share a first number. The second number may end up
+re-used between the two groups.
+
+The resource ID is only used in the big hash, but can be used in the
+context of a course to identify a resource easily. (For instance, the
+printing system uses it to record which resources from a sequence you 
+wish to print.)
+
+X<symb> X<resource, symb>
+All resources also have B<symb>s, which uniquely identify a resource
+in a course. Many internal LON-CAPA functions expect a symb. A symb
+carries along with it the URL of the resource, and the map it appears
+in. Symbs are much larger then resource IDs.
 
 =cut
 
@@ -1757,6 +2996,7 @@ sub new {
 
     # Store this new resource in the parent nav map's cache.
     $self->{NAV_MAP}->{RESOURCE_CACHE}->{$self->{ID}} = $self;
+    $self->{RESOURCE_ERROR} = 0;
 
     # A hash that can be used by two-pass algorithms to store data
     # about this resource in. Not used by the resource object
@@ -1768,38 +3008,88 @@ sub new {
     return $self;
 }
 
+# private function: simplify the NAV_HASH lookups we keep doing
+# pass the name, and to automatically append my ID, pass a true val on the
+# second param
+sub navHash {
+    my $self = shift;
+    my $param = shift;
+    my $id = shift;
+    return $self->{NAV_MAP}->navhash($param . ($id?$self->{ID}:""));
+}
+
 =pod
 
-=item * B<is_map>: Returns true if this is a map, false otherwise.
+=head2 Methods
+
+Once you have a resource object, here's what you can do with it:
+
+=head3 Attribute Retrieval
+
+Every resource has certain attributes that can be retrieved and used:
+
+=over 4
+
+=item * B<ID>: Every resource has an ID that is unique for that
+    resource in the course it is in. The ID is actually in the hash
+    representing the resource, so for a resource object $res, obtain
+    it via C<$res->{ID}).
+
+=item * B<compTitle>:
+
+Returns a "composite title", that is equal to $res->title() if the
+resource has a title, and is otherwise the last part of the URL (e.g.,
+"problem.problem").
+
+=item * B<ext>:
+
+Returns true if the resource is external.
+
+=item * B<kind>:
+
+Returns the kind of the resource from the compiled nav map.
+
+=item * B<randomout>:
+
+Returns true if this resource was chosen to NOT be shown to the user
+by the random map selection feature. In other words, this is usually
+false.
+
+=item * B<randompick>:
+
+Returns true for a map if the randompick feature is being used on the
+map. (?)
+
+=item * B<src>:
+
+Returns the source for the resource.
 
-=item * B<title>: Returns title.
+=item * B<symb>:
 
-=item * B<type>: Returns the type of the resource, "start", "normal", or "finish". 
+Returns the symb for the resource.
 
-=item * B<problem>: Returns true if the resource is a problem type, false otherwise. (Looks at the extension on the src field.)
+=item * B<title>:
+
+Returns the title of the resource.
 
 =back
 
 =cut
 
-# private function: simplify the NAV_HASH lookups we keep doing
-# pass the name, and to automatically append my ID, pass a true val on the
-# second param
-sub navHash {
-    my $self = shift;
-    my $param = shift;
-    my $id = shift;
-    return $self->{NAV_MAP}->{NAV_HASH}->{$param . ($id?$self->{ID}:"")};
-}
-
 # These info functions can be used directly, as they don't return
 # resource information.
-sub title { my $self=shift; return $self->navHash("title_", 1); }
-sub type { my $self=shift; return $self->navHash("type_", 1); }
+sub comesfrom { my $self=shift; return $self->navHash("comesfrom_", 1); }
+sub ext { my $self=shift; return $self->navHash("ext_", 1) eq 'true:'; }
+sub from { my $self=shift; return $self->navHash("from_", 1); }
+# considered private and undocumented
 sub goesto { my $self=shift; return $self->navHash("goesto_", 1); }
-# "to" can return a comma seperated list for branches
-sub to { my $self=shift; return $self->navHash("to_", 1); }
 sub kind { my $self=shift; return $self->navHash("kind_", 1); }
+sub randomout { my $self=shift; return $self->navHash("randomout_", 1); }
+sub randompick { 
+    my $self = shift;
+    return $self->{NAV_MAP}->{PARM_HASH}->{$self->symb .
+                                               '.0.parameter_randompick'};
+}
 sub src { 
     my $self=shift;
     return $self->navHash("src_", 1);
@@ -1808,78 +3098,157 @@ sub symb {
     my $self=shift;
     (my $first, my $second) = $self->{ID} =~ /(\d+).(\d+)/;
     my $symbSrc = &Apache::lonnet::declutter($self->src());
-    return &Apache::lonnet::declutter(
-         $self->navHash('map_id_'.$first)) 
+    my $symb = &Apache::lonnet::declutter($self->navHash('map_id_'.$first)) 
         . '___' . $second . '___' . $symbSrc;
+    return &Apache::lonnet::symbclean($symb);
 }
-sub is_problem {
-    my $self=shift;
-    my $src = $self->src();
-    return ($src =~ /problem$/);
+sub title { 
+    my $self=shift; 
+    if ($self->{ID} eq '0.0') {
+	# If this is the top-level map, return the title of the course
+	# since this map can not be titled otherwise.
+	return $ENV{'course.'.$ENV{'request.course.id'}.'.description'};
+    }
+    return $self->navHash("title_", 1); }
+# considered private and undocumented
+sub to { my $self=shift; return $self->navHash("to_", 1); }
+sub compTitle {
+    my $self = shift;
+    my $title = $self->title();
+    $title=~s/\&colon\;/\:/gs;
+    if (!$title) {
+        $title = $self->src();
+        $title = substr($title, rindex($title, '/') + 1);
+    }
+    return $title;
 }
+=pod
+
+B<Predicate Testing the Resource>
+
+These methods are shortcuts to deciding if a given resource has a given property.
+
+=over 4
+
+=item * B<is_map>:
+
+Returns true if the resource is a map type.
+
+=item * B<is_problem>:
+
+Returns true if the resource is a problem type, false
+otherwise. (Looks at the extension on the src field; might need more
+to work correctly.)
+
+=item * B<is_page>:
+
+Returns true if the resource is a page.
+
+=item * B<is_sequence>:
+
+Returns true if the resource is a sequence.
+
+=back
+
+=cut
+
+
 sub is_html {
     my $self=shift;
     my $src = $self->src();
     return ($src =~ /html$/);
 }
-sub is_sequence {
+sub is_map { my $self=shift; return defined($self->navHash("is_map_", 1)); }
+sub is_page {
     my $self=shift;
     my $src = $self->src();
-    return ($src =~ /sequence$/);
+    return $self->navHash("is_map_", 1) && 
+	$self->navHash("map_type_" . $self->map_pc()) eq 'page';
 }
-sub is_page {
+sub is_problem {
     my $self=shift;
     my $src = $self->src();
-    return ($src =~ /page$/);
+    return ($src =~ /problem$/);
+}
+sub is_sequence {
+    my $self=shift;
+    my $src = $self->src();
+    return $self->navHash("is_map_", 1) && 
+	$self->navHash("map_type_" . $self->map_pc()) eq 'sequence';
 }
 
-
-
-
-# Move this into POD: In order to use these correctly, courseopt
-# and useropt need to be generated
+# Private method: Shells out to the parmval in the nav map, handler parts.
 sub parmval {
     my $self = shift;
     my $what = shift;
-    my $part = shift || "0";
+    my $part = shift;
+    if (!defined($part)) { 
+        $part = '0'; 
+    }
     return $self->{NAV_MAP}->parmval($part.'.'.$what, $self->symb());
 }
 
-#####
-# Map Queries
-#####
+=pod
 
-# These methods relate to whether or not the resource is a map, and the 
-# attributes of that map.
+B<Map Methods>
+
+These methods are useful for getting information about the map
+properties of the resource, if the resource is a map (B<is_map>).
+
+=over 4
+
+=item * B<map_finish>:
+
+Returns a reference to a resource object corresponding to the finish
+resource of the map.
+
+=item * B<map_pc>:
+
+Returns the pc value of the map, which is the first number that
+appears in the resource ID of the resources in the map, and is the
+number that appears around the middle of the symbs of the resources in
+that map.
+
+=item * B<map_start>:
+
+Returns a reference to a resource object corresponding to the start
+resource of the map.
+
+=item * B<map_type>:
+
+Returns a string with the type of the map in it.
+
+=back
+
+=cut
 
-sub is_map { my $self=shift; return defined($self->navHash("is_map_", 1)); }
 sub map_finish {
     my $self = shift;
     my $src = $self->src();
+    $src = Apache::lonnet::clutter($src);
     my $res = $self->navHash("map_finish_$src", 0);
     $res = $self->{NAV_MAP}->getById($res);
     return $res;
 }
+sub map_pc {
+    my $self = shift;
+    my $src = $self->src();
+    return $self->navHash("map_pc_$src", 0);
+}
 sub map_start {
     my $self = shift;
     my $src = $self->src();
+    $src = Apache::lonnet::clutter($src);
     my $res = $self->navHash("map_start_$src", 0);
     $res = $self->{NAV_MAP}->getById($res);
     return $res;
 }
-sub map_pc {
-    my $self = shift;
-    my $src = $self->src();
-    return $self->navHash("map_pc_$src", 0);
-}
 sub map_type {
     my $self = shift;
     my $pc = $self->map_pc();
     return $self->navHash("map_type_$pc", 0);
 }
 
-
-
 #####
 # Property queries
 #####
@@ -1894,31 +3263,69 @@ sub map_type {
 
 =head2 Resource Parameters
 
-In order to use the resource parameters correctly, the nav map must have been instantiated with genCourseAndUserOptions set to true, so the courseopt and useropt is read correctly. Then, you can call these functions to get the relevant parameters for the resource. Each function defaults to "part 0", but can be directed to another part by passing the part as the second parameter.
-
-These methods are responsible for getting the parameter correct, not merely reflecting the contents of the GDBM hashes. As we move towards dates relative to other dates, these methods should be updated to reflect that. (Then, anybody using these methods won't have to update their code.)
+In order to use the resource parameters correctly, the nav map must
+have been instantiated with genCourseAndUserOptions set to true, so
+the courseopt and useropt is read correctly. Then, you can call these
+functions to get the relevant parameters for the resource. Each
+function defaults to part "0", but can be directed to another part by
+passing the part as the parameter.
+
+These methods are responsible for getting the parameter correct, not
+merely reflecting the contents of the GDBM hashes. As we move towards
+dates relative to other dates, these methods should be updated to
+reflect that. (Then, anybody using these methods will not have to update
+their code.)
 
 =over 4
 
-=item * B<acc>: Get the Client IP/Name Access Control information.
+=item * B<acc>:
+
+Get the Client IP/Name Access Control information.
+
+=item * B<answerdate>:
+
+Get the answer-reveal date for the problem.
+
+=item * B<awarded>: 
+
+Gets the awarded value for the problem part. Requires genUserData set to
+true when the navmap object was created.
+
+=item * B<duedate>:
+
+Get the due date for the problem.
+
+=item * B<tries>:
+
+Get the number of tries the student has used on the problem.
 
-=item * B<answerdate>: Get the answer-reveal date for the problem.
+=item * B<maxtries>:
 
-=item * B<duedate>: Get the due date for the problem.
+Get the number of max tries allowed.
 
-=item * B<tries>: Get the number of tries the student has used on the problem.
+=item * B<opendate>:
 
-=item * B<maxtries>: Get the number of max tries allowed.
+Get the open date for the problem.
 
-=item * B<opendate>: Get the open date for the problem.
+=item * B<sig>:
 
-=item * B<sig>: Get the significant figures setting.
+Get the significant figures setting.
 
-=item * B<tol>: Get the tolerance for the problem.
+=item * B<tol>:
 
-=item * B<type>: Get the question type for the problem.
+Get the tolerance for the problem.
 
-=item * B<weight>: Get the weight for the problem.
+=item * B<tries>:
+
+Get the number of tries the user has already used on the problem.
+
+=item * B<type>:
+
+Get the question type for the problem.
+
+=item * B<weight>:
+
+Get the weight for the problem.
 
 =back
 
@@ -1937,6 +3344,12 @@ sub answerdate {
     }
     return $self->parmval("answerdate", $part);
 }
+sub awarded { 
+    my $self = shift; my $part = shift;
+    $self->{NAV_MAP}->get_user_data();
+    if (!defined($part)) { $part = '0'; }
+    return $self->{NAV_MAP}->{STUDENT_DATA}->{$self->symb()}->{'resource.'.$part.'.awarded'};
+}
 sub duedate {
     (my $self, my $part) = @_;
     return $self->parmval("duedate", $part);
@@ -1953,6 +3366,10 @@ sub opendate {
     }
     return $self->parmval("opendate");
 }
+sub problemstatus {
+    (my $self, my $part) = @_;
+    return lc $self->parmval("problemstatus", $part);
+}
 sub sig {
     (my $self, my $part) = @_;
     return $self->parmval("sig", $part);
@@ -1961,25 +3378,24 @@ sub tol {
     (my $self, my $part) = @_;
     return $self->parmval("tol", $part);
 }
+sub tries { 
+    my $self = shift; 
+    my $tries = $self->queryRestoreHash('tries', shift);
+    if (!defined($tries)) { return '0';}
+    return $tries;
+}
 sub type {
     (my $self, my $part) = @_;
     return $self->parmval("type", $part);
 }
-sub weight {
-    (my $self, my $part) = @_;
-    return $self->parmval("weight", $part);
-}
-sub tries {
-    my $self = shift;
-    my $part = shift;
-    $part = '0' if (!defined($part));
+sub weight { 
+    my $self = shift; my $part = shift;
+    if (!defined($part)) { $part = '0'; }
+    return &Apache::lonnet::EXT('resource.'.$part.'.weight',
+				$self->symb(), $ENV{'user.domain'},
+				$ENV{'user.name'}, 
+				$ENV{'request.course.sec'});
 
-    # Make sure return hash is loaded, should error check
-    $self->getReturnHash();
-    
-    my $tries = $self->{RETURN_HASH}->{'resource.'.$part.'.tries'};
-    if (!defined($tries)) {return '0';}
-    return $tries;
 }
 
 # Multiple things need this
@@ -1987,7 +3403,7 @@ sub getReturnHash {
     my $self = shift;
     
     if (!defined($self->{RETURN_HASH})) {
-        my %tmpHash = &Apache::lonnet::restore($self->symb());
+        my %tmpHash  = &Apache::lonnet::restore($self->symb());
         $self->{RETURN_HASH} = \%tmpHash;
     }
 }       
@@ -2014,9 +3430,75 @@ Misc. functions for the resource.
 
 =over 4
 
-=item * B<parts>(): Returns a list reference containing sorted strings corresponding to each part of the problem. To count the number of parts, use the list in a scalar context, and subtract one if greater then two. (One part problems have a part 0. Multi-parts have a part 0, plus a part for each part. You may or may not wish to filter out part 0.)
+=item * B<hasDiscussion>:
+
+Returns a false value if there has been discussion since the user last
+logged in, true if there has. Always returns false if the discussion
+data was not extracted when the nav map was constructed.
+
+=item * B<getFeedback>:
 
-=item * B<countParts>(): Returns the number of parts of the problem a student can answer. Thus, for single part problems, returns 1. For multipart, it returns the number of parts in the problem, not including psuedo-part 0.
+Gets the feedback for the resource and returns the raw feedback string
+for the resource, or the null string if there is no feedback or the
+email data was not extracted when the nav map was constructed. Usually
+used like this:
+
+ for (split(/\,/, $res->getFeedback())) {
+    my $link = &Apache::lonnet::escape($_);
+    ...
+
+and use the link as appropriate.
+
+=cut
+
+sub hasDiscussion {
+    my $self = shift;
+    return $self->{NAV_MAP}->hasDiscussion($self->symb());
+}
+
+sub getFeedback {
+    my $self = shift;
+    my $source = $self->src();
+    if ($source =~ /^\/res\//) { $source = substr $source, 5; }
+    return $self->{NAV_MAP}->getFeedback($source);
+}
+
+sub getErrors {
+    my $self = shift;
+    my $source = $self->src();
+    if ($source =~ /^\/res\//) { $source = substr $source, 5; }
+    return $self->{NAV_MAP}->getErrors($source);
+}
+
+=pod
+
+=item * B<parts>():
+
+Returns a list reference containing sorted strings corresponding to
+each part of the problem. Single part problems have only a part '0'.
+Multipart problems do not return their part '0', since they typically
+do not really matter. 
+
+=item * B<countParts>():
+
+Returns the number of parts of the problem a student can answer. Thus,
+for single part problems, returns 1. For multipart, it returns the
+number of parts in the problem, not including psuedo-part 0. 
+
+=item * B<multipart>():
+
+Returns true if the problem is multipart, false otherwise. Use this instead
+of countParts if all you want is multipart/not multipart.
+
+=item * B<responseType>($part):
+
+Returns the response type of the part, without the word "response" on the
+end. Example return values: 'string', 'essay', 'numeric', etc.
+
+=item * B<responseIds>($part):
+
+Retreives the response IDs for the given part as an array reference containing
+strings naming the response IDs. This may be empty.
 
 =back
 
@@ -2025,6 +3507,8 @@ Misc. functions for the resource.
 sub parts {
     my $self = shift;
 
+    if ($self->ext) { return []; }
+
     $self->extractParts();
     return $self->{PARTS};
 }
@@ -2033,31 +3517,134 @@ sub countParts {
     my $self = shift;
     
     my $parts = $self->parts();
-    
-    if (scalar(@{$parts}) == 1) { return 1;}
 
-    return scalar(@{$parts}) - 1;
+    # If I left this here, then it's not necessary.
+    #my $delta = 0;
+    #for my $part (@$parts) {
+    #    if ($part eq '0') { $delta--; }
+    #}
+
+    if ($self->{RESOURCE_ERROR}) {
+        return 0;
+    }
+
+    return scalar(@{$parts}); # + $delta;
+}
+
+sub multipart {
+    my $self = shift;
+    return $self->countParts() > 1;
+}
+
+sub singlepart {
+    my $self = shift;
+    return $self->countParts() == 1;
+}
+
+sub responseType {
+    my $self = shift;
+    my $part = shift;
+
+    $self->extractParts();
+    if (defined($self->{RESPONSE_TYPES}->{$part})) {
+	return @{$self->{RESPONSE_TYPES}->{$part}};
+    } else {
+	return undef;
+    }
+}
+
+sub responseIds {
+    my $self = shift;
+    my $part = shift;
+
+    $self->extractParts();
+    if (defined($self->{RESPONSE_IDS}->{$part})) {
+	return @{$self->{RESPONSE_IDS}->{$part}};
+    } else {
+	return undef;
+    }
 }
 
-# Private function: Extracts the parts information and saves it
+# Private function: Extracts the parts information, both part names and
+# part types, and saves it. 
 sub extractParts { 
     my $self = shift;
     
-    return if ($self->{PARTS});
+    return if (defined($self->{PARTS}));
+    return if ($self->ext);
 
     $self->{PARTS} = [];
 
-    # Retrieve part count
-    foreach (split(/\,/,&Apache::lonnet::metadata($self->src(), 
-                                                  'allpossiblekeys'))) {
-        if ($_ =~ /^parameter\_(.*)\_opendate$/) {
-            push @{$self->{PARTS}}, $1;
+    my %parts;
+
+    # Retrieve part count, if this is a problem
+    if ($self->is_problem()) {
+        my $metadata = &Apache::lonnet::metadata($self->src(), 'packages');
+        if (!$metadata) {
+            $self->{RESOURCE_ERROR} = 1;
+            $self->{PARTS} = [];
+            $self->{PART_TYPE} = {};
+            return;
         }
+        foreach (split(/\,/,$metadata)) {
+            if ($_ =~ /^part_(.*)$/) {
+                my $part = $1;
+                # This floods the logs if it blows up
+                if (defined($parts{$part})) {
+                    Apache::lonnet::logthis("$part multiply defined in metadata for " . $self->symb());
+                  }
+
+                # check to see if part is turned off.
+
+                if (!Apache::loncommon::check_if_partid_hidden($part, $self->symb())) {
+                    $parts{$part} = 1;
+                }
+            }
+        }
+        
+        
+        my @sortedParts = sort keys %parts;
+        $self->{PARTS} = \@sortedParts;
+
+        my %responseIdHash;
+        my %responseTypeHash;
+
+
+        # Init the responseIdHash
+        foreach (@{$self->{PARTS}}) {
+            $responseIdHash{$_} = [];
+        }
+
+        # Now, the unfortunate thing about this is that parts, part name, and
+        # response if are delimited by underscores, but both the part
+        # name and response id can themselves have underscores in them.
+        # So we have to use our knowlege of part names to figure out 
+        # where the part names begin and end, and even then, it is possible
+        # to construct ambiguous situations.
+        foreach (split /,/, $metadata) {
+            if ($_ =~ /^([a-zA-Z]+)response_(.*)/) {
+                my $responseType = $1;
+                my $partStuff = $2;
+                my $partIdSoFar = '';
+                my @partChunks = split /_/, $partStuff;
+                my $i = 0;
+
+                for ($i = 0; $i < scalar(@partChunks); $i++) {
+                    if ($partIdSoFar) { $partIdSoFar .= '_'; }
+                    $partIdSoFar .= $partChunks[$i];
+                    if ($parts{$partIdSoFar}) {
+                        my @otherChunks = @partChunks[$i+1..$#partChunks];
+                        my $responseId = join('_', @otherChunks);
+                        push @{$responseIdHash{$partIdSoFar}}, $responseId;
+                        push @{$responseTypeHash{$partIdSoFar}}, $responseType;
+                    }
+                }
+            }
+        }
+
+        $self->{RESPONSE_IDS} = \%responseIdHash;
+        $self->{RESPONSE_TYPES} = \%responseTypeHash;
     }
-    
-    # Is this possible to do in one line? - Jeremy
-    my @sortedParts = sort @{$self->{PARTS}};
-    $self->{PARTS} = \@sortedParts;
 
     return;
 }
@@ -2066,22 +3653,40 @@ sub extractParts {
 
 =head2 Resource Status
 
-Problem resources have status information, reflecting their various dates and completion statuses. You can obtain this information and import symbolic constants to represent the status.
+Problem resources have status information, reflecting their various
+dates and completion statuses.
 
-There are two aspects to the status: the date-related information and the completion information.
+There are two aspects to the status: the date-related information and
+the completion information.
 
-Idiomatic usage of these two methods would probably look something like
+Idiomatic usage of these two methods would probably look something
+like
 
  foreach ($resource->parts()) {
     my $dateStatus = $resource->getDateStatus($_);
     my $completionStatus = $resource->getCompletionStatus($_);
 
+    or
+
+    my $status = $resource->status($_);
+
     ... use it here ...
  }
 
+Which you use depends on exactly what you are looking for. The
+status() function has been optimized for the nav maps display and may
+not precisely match what you need elsewhere.
+
+The symbolic constants shown below can be accessed through the
+resource object: C<$res->OPEN>.
+
 =over 4
 
-=item * B<getDateStatus>($part): ($part defaults to 0). A convenience function that returns a symbolic constant telling you about the date status of the part, with the following possible results:
+=item * B<getDateStatus>($part):
+
+($part defaults to 0). A convenience function that returns a symbolic
+constant telling you about the date status of the part. The possible
+return values are:
 
 =back
 
@@ -2089,17 +3694,30 @@ B<Date Codes>
 
 =over 4
 
-=item * B<OPEN_LATER>: The problem will be opened later.
+=item * B<OPEN_LATER>:
 
-=item * B<OPEN>: Open and not yet due.
+The problem will be opened later.
 
-=item * B<PAST_DUE_ANSWER_LATER>: The due date has passed, but the answer date has not yet arrived.
+=item * B<OPEN>:
 
-=item * B<PAST_DUE_NO_ANSWER>: The due date has passed and there is no answer opening date set.
+Open and not yet due.
 
-=item * B<ANSWER_OPEN>: The answer date is here.
 
-=item * B<NETWORK_FAILURE>: The information is unknown due to network failure.
+=item * B<PAST_DUE_ANSWER_LATER>:
+
+The due date has passed, but the answer date has not yet arrived.
+
+=item * B<PAST_DUE_NO_ANSWER>:
+
+The due date has passed and there is no answer opening date set.
+
+=item * B<ANSWER_OPEN>:
+
+The answer date is here.
+
+=item * B<NETWORK_FAILURE>:
+
+The information is unknown due to network failure.
 
 =back
 
@@ -2140,10 +3758,10 @@ sub getDateStatus {
         # should this be the same as "open later"? think multipart.
         return $self->NOTHING_SET;
     }
-    if (!$open || $now < $open) {return $self->OPEN_LATER};
-    if (!$due || $now < $due) {return $self->OPEN};
-    if ($answer && $now < $answer) {return $self->PAST_DUE_ANSWER_LATER};
-    if ($answer) { return $self->ANSWER_OPEN; };
+    if (!$open || $now < $open) {return $self->OPEN_LATER}
+    if (!$due || $now < $due) {return $self->OPEN}
+    if ($answer && $now < $answer) {return $self->PAST_DUE_ANSWER_LATER}
+    if ($answer) { return $self->ANSWER_OPEN; }
     return PAST_DUE_NO_ANSWER;
 }
 
@@ -2153,27 +3771,49 @@ B<>
 
 =over 4
 
-=item * B<getCompletionStatus>($part): ($part defaults to 0.) A convenience function that returns a symbolic constant telling you about the completion status of the part, with the following possible results:
+=item * B<getCompletionStatus>($part):
 
-=back 
+($part defaults to 0.) A convenience function that returns a symbolic
+constant telling you about the completion status of the part, with the
+following possible results:
+
+=back
 
 B<Completion Codes>
 
 =over 4
 
-=item * B<NOT_ATTEMPTED>: Has not been attempted at all.
+=item * B<NOT_ATTEMPTED>:
+
+Has not been attempted at all.
 
-=item * B<INCORRECT>: Attempted, but wrong by student.
+=item * B<INCORRECT>:
 
-=item * B<INCORRECT_BY_OVERRIDE>: Attempted, but wrong by instructor override.
+Attempted, but wrong by student.
 
-=item * B<CORRECT>: Correct or correct by instructor.
+=item * B<INCORRECT_BY_OVERRIDE>:
 
-=item * B<CORRECT_BY_OVERRIDE>: Correct by instructor override.
+Attempted, but wrong by instructor override.
 
-=item * B<EXCUSED>: Excused. Not yet implemented.
+=item * B<CORRECT>:
 
-=item * B<NETWORK_FAILURE>: Information not available due to network failure.
+Correct or correct by instructor.
+
+=item * B<CORRECT_BY_OVERRIDE>:
+
+Correct by instructor override.
+
+=item * B<EXCUSED>:
+
+Excused. Not yet implemented.
+
+=item * B<NETWORK_FAILURE>:
+
+Information not available due to network failure.
+
+=item * B<ATTEMPTED>:
+
+Attempted, and not yet graded.
 
 =back
 
@@ -2185,17 +3825,13 @@ sub INCORRECT_BY_OVERRIDE { return 12; }
 sub CORRECT               { return 13; }
 sub CORRECT_BY_OVERRIDE   { return 14; }
 sub EXCUSED               { return 15; }
+sub ATTEMPTED             { return 16; }
 
 sub getCompletionStatus {
     my $self = shift;
-    my $part = shift;
-    $part = "0" if (!defined($part));
     return $self->NETWORK_FAILURE if ($self->{NAV_MAP}->{NETWORK_FAILURE});
 
-    # Make sure return hash exists
-    $self->getReturnHash();
-    
-    my $status = $self->{RETURN_HASH}->{'resource.'.$part.'.solved'};
+    my $status = $self->queryRestoreHash('solved', shift);
 
     # Left as seperate if statements in case we ever do more with this
     if ($status eq 'correct_by_student') {return $self->CORRECT;}
@@ -2203,44 +3839,106 @@ sub getCompletionStatus {
     if ($status eq 'incorrect_attempted') {return $self->INCORRECT; }
     if ($status eq 'incorrect_by_override') {return $self->INCORRECT_BY_OVERRIDE; }
     if ($status eq 'excused') {return $self->EXCUSED; }
+    if ($status eq 'ungraded_attempted') {return $self->ATTEMPTED; }
     return $self->NOT_ATTEMPTED;
 }
 
+sub queryRestoreHash {
+    my $self = shift;
+    my $hashentry = shift;
+    my $part = shift;
+    $part = "0" if (!defined($part) || $part eq '');
+    return $self->NETWORK_FAILURE if ($self->{NAV_MAP}->{NETWORK_FAILURE});
+
+    $self->getReturnHash();
+
+    return $self->{RETURN_HASH}->{'resource.'.$part.'.'.$hashentry};
+}
+
 =pod
 
 B<Composite Status>
 
-Along with directly returning the date or completion status, the resource object includes a convenience function B<status>() that will combine the two status tidbits into one composite status that can represent the status of the resource as a whole. The precise logic is documented in the comments of the status method. The following results may be returned, all available as methods on the resource object ($res->NETWORK_FAILURE()):
+Along with directly returning the date or completion status, the
+resource object includes a convenience function B<status>() that will
+combine the two status tidbits into one composite status that can
+represent the status of the resource as a whole. This method represents
+the concept of the thing we want to display to the user on the nav maps
+screen, which is a combination of completion and open status. The precise logic is
+documented in the comments of the status method. The following results
+may be returned, all available as methods on the resource object
+($res->NETWORK_FAILURE): In addition to the return values that match
+the date or completion status, this function can return "ANSWER_SUBMITTED"
+if that problemstatus parameter value is set to No, suppressing the
+incorrect/correct feedback.
 
 =over 4
 
-=item * NETWORK_FAILURE: The network has failed and the information is not available.
+=item * B<NETWORK_FAILURE>:
+
+The network has failed and the information is not available.
+
+=item * B<NOTHING_SET>:
+
+No dates have been set for this problem (part) at all. (Because only
+certain parts of a multi-part problem may be assigned, this can not be
+collapsed into "open later", as we do not know a given part will EVER
+be opened. For single part, this is the same as "OPEN_LATER".)
+
+=item * B<CORRECT>:
+
+For any reason at all, the part is considered correct.
+
+=item * B<EXCUSED>:
+
+For any reason at all, the problem is excused.
+
+=item * B<PAST_DUE_NO_ANSWER>:
 
-=item * NOTHING_SET: No dates have been set for this problem (part) at all. (Because only certain parts of a multi-part problem may be assigned, this can not be collapsed into "open later", as we don't know a given part will EVER be opened.)
+The problem is past due, not considered correct, and no answer date is
+set.
 
-=item * CORRECT: For any reason at all, the part is considered correct.
+=item * B<PAST_DUE_ANSWER_LATER>:
 
-=item * EXCUSED: For any reason at all, the problem is excused.
+The problem is past due, not considered correct, and an answer date in
+the future is set.
 
-=item * PAST_DUE_NO_ANSWER: The problem is past due, not considered correct, and no answer date is set.
+=item * B<ANSWER_OPEN>:
 
-=item * PAST_DUE_ANSWER_LATER: The problem is past due, not considered correct, and an answer date in the future is set.
+The problem is past due, not correct, and the answer is now available.
 
-=item * ANSWER_OPEN: The problem is past due, not correct, and the answer is now available.
+=item * B<OPEN_LATER>:
 
-=item * OPEN_LATER: The problem is not yet open.
+The problem is not yet open.
 
-=item * TRIES_LEFT: The problem is open, has been tried, is not correct, but there are tries left.
+=item * B<TRIES_LEFT>:
 
-=item * INCORRECT: The problem is open, and all tries have been used without getting the correct answer.
+The problem is open, has been tried, is not correct, but there are
+tries left.
 
-=item * OPEN: The item is open and not yet tried.
+=item * B<INCORRECT>:
+
+The problem is open, and all tries have been used without getting the
+correct answer.
+
+=item * B<OPEN>:
+
+The item is open and not yet tried.
+
+=item * B<ATTEMPTED>:
+
+The problem has been attempted.
+
+=item * B<ANSWER_SUBMITTED>:
+
+An answer has been submitted, but the student should not see it.
 
 =back
 
 =cut
 
-sub TRIES_LEFT { return 10; }
+sub TRIES_LEFT       { return 20; }
+sub ANSWER_SUBMITTED { return 21; }
 
 sub status {
     my $self = shift;
@@ -2253,12 +3951,24 @@ sub status {
     # dimension and 5 entries on the other, which we want to colorize,
     # plus network failure and "no date data at all".
 
+    #if ($self->{RESOURCE_ERROR}) { return NETWORK_FAILURE; }
     if ($completionStatus == NETWORK_FAILURE) { return NETWORK_FAILURE; }
 
+    my $suppressFeedback = $self->problemstatus($part) eq 'no';
+    # If there's an answer date and we're past it, don't
+    # suppress the feedback; student should know
+    if ($self->answerdate($part) && $self->answerdate($part) < time()) {
+	$suppressFeedback = 0;
+    }
+
     # There are a few whole rows we can dispose of:
     if ($completionStatus == CORRECT ||
         $completionStatus == CORRECT_BY_OVERRIDE ) {
-        return CORRECT(); 
+        return $suppressFeedback? ANSWER_SUBMITTED : CORRECT; 
+    }
+
+    if ($completionStatus == ATTEMPTED) {
+        return ATTEMPTED;
     }
 
     # If it's EXCUSED, then return that no matter what
@@ -2270,11 +3980,11 @@ sub status {
         return NOTHING_SET;
     }
 
-    # Now we're down to a 3 (incorrect, incorrect_override, not_attempted)
-    # by 4 matrix (date status).
+    # Now we're down to a 4 (incorrect, incorrect_override, not_attempted)
+    # by 4 matrix (date statuses).
 
     if ($dateStatus == PAST_DUE_ANSWER_LATER ||
-        $dateStatus == PAST_DUE_NO_ANSWER) {
+        $dateStatus == PAST_DUE_NO_ANSWER ) {
         return $dateStatus; 
     }
 
@@ -2292,49 +4002,206 @@ sub status {
     # If it's WRONG...
     if ($completionStatus == INCORRECT || $completionStatus == INCORRECT_BY_OVERRIDE) {
         # and there are TRIES LEFT:
-        if ($self->tries() < $self->maxtries()) {
-            return TRIES_LEFT;
+        if ($self->tries($part) < $self->maxtries($part) || !$self->maxtries($part)) {
+            return $suppressFeedback ? ANSWER_SUBMITTED : TRIES_LEFT;
         }
-        return INCORRECT; # otherwise, return orange; student can't fix this
+        return $suppressFeedback ? ANSWER_SUBMITTED : INCORRECT; # otherwise, return orange; student can't fix this
     }
 
     # Otherwise, it's untried and open
     return OPEN; 
 }
 
+sub CLOSED { return 23; }
+sub ERROR { return 24; }
+
 =pod
 
-=head2 Resource/Nav Map Navigation
+B<Simple Status>
+
+Convenience method B<simpleStatus> provides a "simple status" for the resource.
+"Simple status" corresponds to "which icon is shown on the
+Navmaps". There are six "simple" statuses:
 
 =over 4
 
-=item * B<getNext>(): Gets the next resource in the navmap after this one.
+=item * B<CLOSED>: The problem is currently closed. (No icon shown.)
+
+=item * B<OPEN>: The problem is open and unattempted.
+
+=item * B<CORRECT>: The problem is correct for any reason.
+
+=item * B<INCORRECT>: The problem is incorrect and can still be
+completed successfully.
+
+=item * B<ATTEMPTED>: The problem has been attempted, but the student
+does not know if they are correct. (The ellipsis icon.)
+
+=item * B<ERROR>: There is an error retrieving information about this
+problem.
+
+=back
+
+=cut
+
+# This hash maps the composite status to this simple status, and
+# can be used directly, if you like
+my %compositeToSimple = 
+    (
+      NETWORK_FAILURE()       => ERROR,
+      NOTHING_SET()           => CLOSED,
+      CORRECT()               => CORRECT,
+      EXCUSED()               => CORRECT,
+      PAST_DUE_NO_ANSWER()    => INCORRECT,
+      PAST_DUE_ANSWER_LATER() => INCORRECT,
+      ANSWER_OPEN()           => INCORRECT,
+      OPEN_LATER()            => CLOSED,
+      TRIES_LEFT()            => OPEN,
+      INCORRECT()             => INCORRECT,
+      OPEN()                  => OPEN,
+      ATTEMPTED()             => ATTEMPTED,
+      ANSWER_SUBMITTED()      => ATTEMPTED
+     );
+
+sub simpleStatus {
+    my $self = shift;
+    my $part = shift;
+    my $status = $self->status($part);
+    return $compositeToSimple{$status};
+}
+
+=pod
+
+B<simpleStatusCount> will return an array reference containing, in
+this order, the number of OPEN, CLOSED, CORRECT, INCORRECT, ATTEMPTED,
+and ERROR parts the given problem has.
+
+=cut
+    
+# This maps the status to the slot we want to increment
+my %statusToSlotMap = 
+    (
+     OPEN()      => 0,
+     CLOSED()    => 1,
+     CORRECT()   => 2,
+     INCORRECT() => 3,
+     ATTEMPTED() => 4,
+     ERROR()     => 5
+     );
+
+sub statusToSlot { return $statusToSlotMap{shift()}; }
+
+sub simpleStatusCount {
+    my $self = shift;
+
+    my @counts = (0, 0, 0, 0, 0, 0, 0);
+    foreach my $part (@{$self->parts()}) {
+	$counts[$statusToSlotMap{$self->simpleStatus($part)}]++;
+    }
+
+    return \@counts;
+}
+
+=pod
+
+B<Completable>
+
+The completable method represents the concept of I<whether the student can
+currently do the problem>. If the student can do the problem, which means
+that it is open, there are tries left, and if the problem is manually graded
+or the grade is suppressed via problemstatus, the student has not tried it
+yet, then the method returns 1. Otherwise, it returns 0, to indicate that 
+either the student has tried it and there is no feedback, or that for
+some reason it is no longer completable (not open yet, successfully completed,
+out of tries, etc.). As an example, this is used as the filter for the
+"Uncompleted Homework" option for the nav maps.
+
+If this does not quite meet your needs, do not fiddle with it (unless you are
+fixing it to better match the student's conception of "completable" because
+it's broken somehow)... make a new method.
 
 =cut
 
-# For the simple single-link case, to get from a resource to the next
-# resource, you need to look up the "to_" link in the nav hash, then
-# follow that with the "goesto_" link.
+sub completable {
+    my $self = shift;
+    if (!$self->is_problem()) { return 0; }
+    my $partCount = $self->countParts();
+
+    foreach my $part (@{$self->parts()}) {
+        if ($part eq '0' && $partCount != 1) { next; }
+        my $status = $self->status($part);
+        # "If any of the parts are open, or have tries left (implies open),
+        # and it is not "attempted" (manually graded problem), it is
+        # not "complete"
+	if ($self->getCompletionStatus($part) == ATTEMPTED() ||
+	    $status == ANSWER_SUBMITTED() ) {
+	    # did this part already, as well as we can
+	    next;
+	}
+	if ($status == OPEN() || $status == TRIES_LEFT()) {
+	    return 1;
+	}
+    }
+        
+    # If all the parts were complete, so was this problem.
+    return 0;
+}
+
+=pod
+
+=head2 Resource/Nav Map Navigation
+
+=over 4
+
+=item * B<getNext>():
+
+Retreive an array of the possible next resources after this
+one. Always returns an array, even in the one- or zero-element case.
+
+=item * B<getPrevious>():
+
+Retreive an array of the possible previous resources from this
+one. Always returns an array, even in the one- or zero-element case.
+
+=cut
 
 sub getNext {
     my $self = shift;
-    my $alreadySeenHash = shift;
     my @branches;
     my $to = $self->to();
-    foreach my $branch ( split(/\,/, $to) ) {
+    foreach my $branch ( split(/,/, $to) ) {
         my $choice = $self->{NAV_MAP}->getById($branch);
         my $next = $choice->goesto();
         $next = $self->{NAV_MAP}->getById($next);
 
-        # Don't remember it if we've already seen it
-        if (!defined($alreadySeenHash) ||
-            !defined($alreadySeenHash->{$next->{ID}})) {
-                push @branches, $next;
-            }
+        push @branches, $next;
     }
     return \@branches;
 }
 
+sub getPrevious {
+    my $self = shift;
+    my @branches;
+    my $from = $self->from();
+    foreach my $branch ( split /,/, $from) {
+        my $choice = $self->{NAV_MAP}->getById($branch);
+        my $prev = $choice->comesfrom();
+        $prev = $self->{NAV_MAP}->getById($prev);
+
+        push @branches, $prev;
+    }
+    return \@branches;
+}
+
+sub browsePriv {
+    my $self = shift;
+    if (defined($self->{BROWSE_PRIV})) {
+        return $self->{BROWSE_PRIV};
+    }
+
+    $self->{BROWSE_PRIV} = &Apache::lonnet::allowed('bre', $self->src());
+}
+
 =pod
 
 =back