--- loncom/homework/structuretags.pm	2000/08/16 18:32:58	1.3
+++ loncom/homework/structuretags.pm	2002/12/05 22:59:37	1.142
@@ -1,33 +1,847 @@
-# The LearningOnline Network with CAPA
-# <script> definiton
+# The LearningOnline Network with CAPA 
+# definition of tags that give a structure to a document
+#
+# $Id: structuretags.pm,v 1.142 2002/12/05 22:59:37 albertel Exp $
+#
+# Copyright Michigan State University Board of Trustees
+#
+# This file is part of the LearningOnline Network with CAPA (LON-CAPA).
+#
+# LON-CAPA is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# LON-CAPA is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with LON-CAPA; if not, write to the Free Software
+# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+#
+# /home/httpd/html/adm/gpl.txt
+#
+# http://www.lon-capa.org/
+#
+# 2/19 Guy
+# 6/26/2001 fixed extra web display at end of <web></web> tags
+# 8/17,8/18,8/20 Gerd Kortemeyer
 
 
 package Apache::structuretags; 
 
 use strict;
 use Apache::lonnet;
+use Apache::File();
 
-sub BEGIN {
-  &Apache::lonxml::register('Apache::structuretags',('block'));
+BEGIN {
+  &Apache::lonxml::register('Apache::structuretags',('block','while','randomlist','problem','library','web','tex','part','preduedate','postanswerdate','solved','notsolved','startouttext','endouttext'));
+#  &Apache::lonxml::register_insert('problem','',('part','postanswerdate','preduedate'))
+}
+
+sub start_web {
+  my ($target,$token,$tagstack,$parstack,$parser,$safeeval)=@_;
+  my $bodytext=&Apache::lonxml::get_all_text("/web",$$parser[$#$parser]);
+  if ($target eq 'web') {
+    return $bodytext;
+  } 
+  return '';
+}
+
+sub end_web {
+    return '';
+}
+
+sub start_tex {
+  my ($target,$token,$tagstack,$parstack,$parser,$safeeval)=@_;
+  my $bodytext=&Apache::lonxml::get_all_text("/tex",$$parser[$#$parser]);
+  if ($target eq 'tex') {
+      return $bodytext.' ';
+  }
+  return '';
+}
+
+sub end_tex {
+    return '';
+}
+
+sub page_start {
+  my ($target,$token,$tagstack,$parstack,$parser,$safeeval)=@_;
+  my %found;
+  foreach my $taginside ($tagstack) {
+    foreach my $taglookedfor ('html','body','form') {
+      if ($taginside =~ /^$taglookedfor$/i) { $found{$taglookedfor} = 1; }
+    }
+  }
+
+  my $result;
+  my $head_tag_start;
+  if (!defined($found{'html'})) {
+    $result=&Apache::londefdef::start_html($target,$token,$tagstack,$parstack,
+					   $parser,$safeeval);
+    $head_tag_start='<head>'.&Apache::lonxml::registerurl(undef,$target);
+  }
+  my $body_tag_start;
+  if (!defined($found{'body'})) {
+    $body_tag_start='<body onLoad="'.&Apache::lonxml::loadevents().'" '.
+      'onUnload="'.&Apache::lonxml::unloadevents().'" ';
+    my $background=&Apache::lonxml::get_param('background',$parstack,$safeeval);
+    if ($background) {
+      $Apache::lonxml::extlinks[$#Apache::lonxml::extlinks+1]=
+	$background;
+      $body_tag_start.='background="'.$background.'" ';
+    } else {
+      my $bgcolor=&Apache::lonxml::get_param('bgcolor',$parstack,$safeeval);
+      if ($bgcolor) {
+	$body_tag_start.='bgcolor="'.$bgcolor.'" ';
+      } else {
+	$body_tag_start.='bgcolor="#ffffff"';
+      }
+    }
+    $body_tag_start.='>';
+    if ($target eq 'web' && $ENV{'request.state'} ne 'construct') {
+	my ($symb)=&Apache::lonxml::whichuser();
+	if ($symb eq '') {
+	    my $help = &Apache::loncommon::help_open_topic("Ambiguous_Reference");
+	    $help="Browsing or <a href=\"/adm/ambiguous\">ambiguous</a> reference, submissions ignored $help<br />";
+	    $body_tag_start.=$help;
+	}
+    }
+  }
+  my $form_tag_start;
+  if (!defined($found{'form'})) {
+    $form_tag_start='<form name="lonhomework" method="POST" action="'.
+      $ENV{'request.uri'}.'">';
+  }
+  return ($result,$head_tag_start,$body_tag_start,$form_tag_start);
+}
+
+#use Time::HiRes();
+sub get_resource_name {
+  my ($parstack,$safeeval)=@_;
+  my $name=&Apache::lonnet::gettitle();
+  &Apache::lonnet::logthis("Got $name");
+  if ($name eq '') {
+    $name=&Apache::lonnet::EXT('resource.title');
+    if ($name eq 'con_lost') { $name = ''; }
+  }
+  $Apache::lonhomework::name=$name;
+  return $name;
+}
+
+sub setup_rndseed {
+  my ($safeeval)=@_;
+  my $rndseed;
+  if ($ENV{'request.state'} eq "construct") {
+    $rndseed=$ENV{'form.rndseed'};
+    if (!$rndseed) {
+      $rndseed=time;
+      $ENV{'form.rndseed'}=$rndseed;
+    }
+    &Apache::lonxml::debug("Setting rndseed to $rndseed");
+    &Apache::run::run('$external::randomseed='.$rndseed.';',$safeeval);
+  }
+  return $rndseed;
+}
+
+sub problem_edit_header {
+  return '<input type="hidden" name="submitted" value="edit" />
+       <input type="hidden" name="problemmode" value="Edit" />
+       <input type="submit" name="problemmode" value="Discard Edits and View" />
+       <input type="submit" name="problemmode" value="EditXML" />
+       <input type="submit" name="Undo" value="undo" /> <hr />
+       <input type="submit" name="submit" value="Submit Changes and Edit" />
+       <input type="submit" name="submit" value="Submit Changes and View" /><br /><p>&nbsp;</p><table border="0"><tr><td bgcolor="#DDDDDD">
+      ';
+}
+
+sub problem_edit_footer {
+  return '</td></tr></table><br /><input type="submit" name="submit" value="Submit Changes and Edit" />
+    <input type="submit" name="submit" value="Submit Changes and View" />';
+}
+
+sub problem_web_to_edit_header {
+  my ($rndseed)=@_;
+  my $result.='<input type="hidden" name="problemmode" value="View" />
+             <input type="submit" name="problemmode" value="Edit" />
+             <input type="submit" name="problemmode" value="EditXML" />
+             Random Seed:<input type="text" name="rndseed" width="10" value="'.
+	       $rndseed.'" />
+             <input type="submit" name="changerandseed" value="Change" />
+             <input type="submit" name="resetdata" value="Reset Submissions" />
+             <input type="checkbox" name="showallfoils" ';
+  if (defined($ENV{'form.showallfoils'})) { $result.='checked="on"'; }
+  $result.= ' />&nbsp;Show&nbsp;All&nbsp;Foils
+             <hr />';
+  my $numtoanalyze=$ENV{'form.numtoanalyze'};
+  if (!$numtoanalyze) { $numtoanalyze=100; }
+  $result.= '<input type="submit" name="problemmode" value="Answer Distribution" />
+             <input type="text" name="numtoanalyze" value="'.
+	       $numtoanalyze.'" size="5" /> <hr />';
+  return $result;
+}
+
+sub initialize_storage {
+  %Apache::lonhomework::results=();
+  my ($symb,$courseid,$domain,$name) = &Apache::lonxml::whichuser();
+  if ($ENV{'request.state'} eq 'construct') {
+    %Apache::lonhomework::history=
+      &Apache::lonnet::tmprestore($ENV{'request.uri'},'',$domain,$name);
+    my ($temp)=keys %Apache::lonhomework::history ;
+    &Apache::lonxml::debug("Return message of $temp");
+  } else {
+    %Apache::lonhomework::history=
+      &Apache::lonnet::restore($symb,$courseid,$domain,$name);
+  }
+  #ignore error conditions
+  my ($temp)=keys %Apache::lonhomework::history ;
+  if ($temp =~ m/^error:.*/) { %Apache::lonhomework::history=(); }
+}
+
+# -------------------------------------------------------------finalize_storage
+# Stores away the result has to a student's environment
+# checks form.grade_ for specific values, other wises stores
+# to the running users environment
+sub finalize_storage {
+  my $result;
+  my ($temp) = keys %Apache::lonhomework::results;
+  if ( $temp ne '' ) {
+    my ($symb,$courseid,$domain,$name) = &Apache::lonxml::whichuser();
+    if ($ENV{'request.state'} eq 'construct') {
+      $result=&Apache::lonnet::tmpstore(\%Apache::lonhomework::results,
+				      $ENV{'request.uri'},'',$domain,$name);
+      &Apache::lonxml::debug('Construct Store return message:'.$result);
+    } else {
+      $result=&Apache::lonnet::cstore(\%Apache::lonhomework::results,
+				      $symb,$courseid,$domain,$name);
+      &Apache::lonxml::debug('Store return message:'.$result);
+    }
+  }
+  return $result;
+}
+
+sub checkout_msg {
+return (<<ENDCHECKOUT);
+<h2>The resource needs to be checked out</h2>
+As a resource gets checked out, a unique timestamped ID is given to it, and a
+permanent record is left in the system.<p />
+<font color=red>
+Checking out resources is subject to course policies, and may exclude future
+credit even if done erroneously.<p />
+</font>
+<form name="checkout" method="POST" action="$ENV{'request.uri'}">
+<input type="hidden" name="doescheckout" value="yes" />
+<input type="button" name="checkoutbutton" value="Check out Exam for Viewing" onClick="javascript:if (confirm('Check out Exam?')) { document.checkout.submit(); }" />
+</form>
+ENDCHECKOUT
+}
+
+sub start_problem {
+  my ($target,$token,$tagstack,$parstack,$parser,$safeeval)=@_;
+
+  # meta is called from lonpublisher, which doesn't uses the normal
+  # lonhomework method of parsing the file which means that inputtags 
+  # won't get reset
+  if ( $Apache::inputtags::part ne '' && $target != 'meta' ) {
+    &Apache::lonxml::error('Only one problem allowed in a .problem file');
+    my $bodytext=&Apache::lonxml::get_all_text("/problem",$$parser[-1]);
+    return '';
+  }
+#intialize globals
+  $Apache::inputtags::part='0';
+  @Apache::inputtags::responselist = ();
+  @Apache::inputtags::previous=();
+  if ($target ne 'analyze') {
+    &initialize_storage();
+    if ($target eq 'web') {
+      &Apache::lonhomework::showhash(%Apache::lonhomework::history);
+    }
+    $Apache::lonhomework::type=&Apache::lonnet::EXT('resource.0.type');
+    &Apache::lonxml::debug("Found this to be of type :$Apache::lonhomework::type:");
+  }
+  if ($Apache::lonhomework::type eq '') {
+    my $uri=$ENV{'request.uri'};
+    if ($uri=~/\.(\w+)$/) {
+      $Apache::lonhomework::type=$1;
+      &Apache::lonxml::debug("Using type of $1");
+    } else {
+      $Apache::lonhomework::type='problem';
+      &Apache::lonxml::debug("Using default type, problem, :$uri:");
+    }
+  }
+
+  #added vars to the scripting enviroment
+  my $expression='$external::part='.$Apache::inputtags::part.';';
+  &Apache::run::run($expression,$safeeval);
+  my $status;
+  my $accessmsg;
+
+  #should get back a <html> or the neccesary stuff to start XML/MathML
+  my ($result,$head_tag_start,$body_tag_start,$form_tag_start)=
+    &page_start($target,$token,$tagstack,$parstack,$parser,$safeeval);
+  if ($target eq 'tex' and $ENV{'request.symb'} =~ m/\.page_/) { $result = '';}
+
+  if ($target eq 'analyze') { my $rndseed=&setup_rndseed($safeeval); }
+  if ($target eq 'web' || $target eq 'grade' || $target eq 'answer' || $target eq 'tex') {
+    #handle exam checkout
+    if ($Apache::lonhomework::type eq 'exam') {
+      my $token=$Apache::lonhomework::history{"resource.0.outtoken"};
+      if (($ENV{'form.doescheckout'}) && (!$token)) {
+	$token=&Apache::lonxml::maketoken();
+	$Apache::lonhomework::history{"resource.0.outtoken"}=$token;
+      }
+      $body_tag_start.=&Apache::lonxml::printtokenheader($target,$token);
+    }
+
+    #handle rand seed in construction space
+    my $rndseed=&setup_rndseed($safeeval);
+    ($status,$accessmsg) = &Apache::lonhomework::check_access('0');
+    push (@Apache::inputtags::status,$status);
+    my $expression='$external::datestatus="'.$status.'";';
+    $expression.='$external::gradestatus="'.$Apache::lonhomework::history{"resource.0.solved"}.'";';
+    &Apache::run::run($expression,$safeeval);
+    &Apache::lonxml::debug("Got $status");
+    if (( $status eq 'CLOSED' ) ||
+        ( $status eq 'UNCHECKEDOUT') ||
+        ( $status eq 'BANNED') ||
+        ( $status eq 'UNAVAILABLE')) {
+      my $bodytext=&Apache::lonxml::get_all_text("/problem",$parser);
+      if ( $target eq "web" ) {
+	$result.= $head_tag_start.'</head>';
+        my $msg=$body_tag_start;
+	if ($status eq 'UNAVAILABLE') {
+	    $result.='<h1>Unable to determine if this resource is open due to network problems. Please try again later.</h1>';
+	} else {
+	    $result.='<h1>Not open to be viewed</h1>';
+	}
+        if ($status eq 'CLOSED') {
+	    $msg.='The problem '.$accessmsg;
+	} elsif ($status eq 'UNCHECKEDOUT') {
+            $msg.=&checkout_msg;
+        }
+	$result.=$msg.'<br />';
+      } elsif ($target eq 'tex') {
+	  $result.="\\begin{document}\\noindent \\vskip 1 mm \\begin{minipage}{\\textwidth}\\vskip 0 mm ";
+	if ($status eq 'UNAVAILABLE') {
+	    $result.='Unable to determine if this resource is open due to network problems. Please try again later.\vskip 0 mm ';
+	} else {
+	    $result.="Problem is not open to be viewed. It $accessmsg \\vskip 0 mm ";
+	}
+      }
+    } elsif ($target eq 'web') {
+      my $name= &get_resource_name($parstack,$safeeval);
+      if ($status eq 'CAN_ANSWER') {
+	# create a page header and exit
+	$result.="$head_tag_start<title>$name</title></head>
+              $body_tag_start \n $form_tag_start".	
+		'<input type="hidden" name="submitted" value="yes" />';
+	if ($ENV{'request.state'} eq "construct") {
+	  $result.= &problem_web_to_edit_header($rndseed);
+	}
+	# if we are viewing someone else preserve that info
+	if (defined $ENV{'form.grade_symb'}) {
+	  foreach my $field ('symb','courseid','domain','username') {
+	    $result .= '<input type="hidden" name="grade_'.$field.
+	      '" value="'.$ENV{"form.grade_$field"}.'" />'."\n";
+	  }
+	}
+      } elsif ($status eq 'SHOW_ANSWER' || $status eq 'CANNOT_ANSWER'
+	       || $status eq 'CLOSED' || $status eq 'UNAVALAILABLE') {
+	$result.=$head_tag_start.
+	  "<title>$name</title></head>\n$body_tag_start\n";
+      }
+    } elsif ($target eq 'tex') {
+	my $name= &Apache::lonxml::get_param('name',$parstack,$safeeval);
+	if ($name eq '') { 
+	    $name=&Apache::lonnet::EXT('resource.title');
+	    if ($name eq 'con_lost') { $name = ''; }
+	}
+	$Apache::lonhomework::name=$name;
+	my $id = $Apache::inputtags::part;
+	my $duedate = &Apache::lonnet::EXT("resource.$id.duedate"); 
+	$duedate = POSIX::strftime("%c",localtime($duedate));
+	my $temp_file;
+	my $filename = "/home/httpd/prtspool/$ENV{'user.name'}_$ENV{'user.domain'}_printout.due";
+        if (-e $filename) {
+	    $temp_file = Apache::File->new($filename); 
+	} else {
+	    $temp_file = Apache::File->new('>>'.$filename); 
+	}
+	my @due_file_content = <$temp_file>;
+	my $due_file_content = $due_file_content[$#due_file_content];
+        chomp $due_file_content;
+        if ($due_file_content ne $duedate) {	    
+	$temp_file = Apache::File->new('>'.$filename); 
+	    print $temp_file "$duedate\n";	    
+	    if (not $ENV{'request.symb'} =~ m/\.page_/) {
+		if(not $duedate=~m/1969/) {
+		    $result .= '\begin{document} \noindent\textit{Due date: '.$duedate.'} \vskip 1 mm\noindent \begin{minipage}{\textwidth}';	
+		} else {
+		    $result .= '\begin{document} \noindent \vskip 1 mm \noindent\begin{minipage}{\textwidth}';
+		}
+	    } else {
+		$result .= '\vskip 1mm\textit{Due date: '.$duedate.'} \\\\\\\\';
+	    } 
+	} else {
+	    if (not $ENV{'request.symb'} =~ m/\.page_/) {
+		$result .= '\begin{document} \noindent \vskip 1 mm\noindent\begin{minipage}{\textwidth}';	
+	    } else {
+		$result .= '\vskip 1mm \\\\\\\\';
+	    } 
+	}
+    }
+  } elsif ($target eq 'edit') {
+    $result.=$head_tag_start."</head>".$body_tag_start.$form_tag_start.
+      &problem_edit_header();
+    my $temp=&Apache::edit::insertlist($target,$token);
+    $result.=$temp;
+  } elsif ($target eq 'modified') {
+    $result=$token->[4];
+    $result.=&Apache::edit::handle_insert();
+  } else {
+    # page_start returned a starting result, delete it if we don't need it
+    $result = '';
+  }
+  return $result;
+}
+
+sub end_problem {
+  my ($target,$token,$tagstack,$parstack,$parser,$safeeval)=@_;
+  my $result='';
+  my $status=$Apache::inputtags::status['-1'];
+  if ($target eq 'grade' || $target eq 'web' || $target eq 'answer' || $target eq 'tex') {
+    if ( $target eq 'grade' && $Apache::inputtags::part eq '0') {
+      # if part is zero, no <part>s existed, so we need to the grading
+      &Apache::inputtags::grade;
+    } elsif ( ($target eq 'web' || $target eq 'tex') && $Apache::inputtags::part eq '0' && 
+	      $status ne 'UNCHECKEDOUT') {
+      # if part is zero, no <part>s existed, so we need show the current 
+      # grading status
+      my $gradestatus = &Apache::inputtags::gradestatus($Apache::inputtags::part,$target);
+      if ($Apache::lonhomework::type ne 'exam') {$result.= $gradestatus;}
+    }
+    if (
+	(($target eq 'web') && ($ENV{'request.state'} ne 'construct')) ||
+	($target eq 'answer') || ($target eq 'tex')
+       ) {
+      if ($status eq 'CAN_ANSWER') {
+	  if ($target ne 'tex') {
+	      $result.="</form></body>\n";
+	  } 
+      } elsif ($status eq 'SHOW_ANSWER' || $status eq 'CANNOT_ANSWER' ||
+	       $status eq 'UNCHECKEDOUT' ) {
+	  if ($target ne 'tex') {
+	      $result.="</body>\n";
+	  }
+      }
+      if ($target eq 'web') {
+	  $result.=&Apache::lonxml::xmlend();
+      } elsif ($target eq 'tex') {
+	  $result .= '\vskip 0.5mm\noindent\makebox[\textwidth/$number_of_columns][b]{\hrulefill}';
+	  if (not $ENV{'request.symb'} =~ m/\.page_/) {
+	      $result .= '\end{minipage}\end{document} ';
+	  } else {
+	      $result .= '';
+	  }
+      }
+    }
+    if ($target eq 'grade') { 
+      &Apache::lonhomework::showhash(%Apache::lonhomework::results);
+      &finalize_storage();
+    }
+  } elsif ($target eq 'meta') {
+    if ($Apache::inputtags::part eq '0') {
+      $result=&Apache::response::mandatory_part_meta;
+    }
+  } elsif ($target eq 'edit') {
+    &Apache::lonxml::debug("in end_problem with $target, edit");
+    $result = &problem_edit_footer();
+  }
+  return $result;
+}
+
+
+sub start_library {
+  my ($target,$token,$tagstack,$parstack,$parser,$safeeval)=@_;
+  my ($result,$head_tag_start,$body_tag_start,$form_tag_start);
+
+  if ($target eq 'edit') {
+    ($result,$head_tag_start,$body_tag_start,$form_tag_start)=
+      &page_start($target,$token,$tagstack,$parstack,$parser,$safeeval);
+    $result.=$head_tag_start."</head>".$body_tag_start.$form_tag_start.
+      &problem_edit_header();
+    my $temp=&Apache::edit::insertlist($target,$token);
+    $result.=$temp;
+  } elsif ($target eq 'modified') {
+    $result=$token->[4];
+    $result.=&Apache::edit::handle_insert();
+  } elsif ($target eq 'web' && $$tagstack[0] ne 'problem' &&
+	   $ENV{'request.state'} eq "construct" ) {
+    ($result,$head_tag_start,$body_tag_start,$form_tag_start)=
+      &page_start($target,$token,$tagstack,$parstack,$parser,$safeeval);
+    my $name=&get_resource_name($parstack,$safeeval);
+    my $rndseed=&setup_rndseed($safeeval);
+    $result.="$head_tag_start<title>$name</title></head>
+              $body_tag_start \n $form_tag_start".	
+		'<input type="hidden" name="submitted" value="yes" />';
+    $result.=&problem_web_to_edit_header($rndseed);
+  }
+  return $result;
+}
+
+sub end_library {
+  my ($target,$token,$tagstack,$parstack,$parser,$safeeval)=@_;
+  my $result='';
+  if ($target eq 'edit') {
+    $result=&problem_edit_footer();
+  } elsif ($target eq 'web' && $$tagstack[0] ne 'problem' &&
+	   $ENV{'request.state'} eq "construct") {
+    $result.='</form></body>'.&Apache::lonxml::xmlend();
+  }
+  return $result;
 }
 
 sub start_block {
-  my ($target,$token,$parstack,$parser,$safeeval)=@_;
+    my ($target,$token,$tagstack,$parstack,$parser,$safeeval)=@_;
+
+    my $result;
+
+    if ($target eq 'web' || $target eq 'grade' || $target eq 'answer' || 
+	$target eq 'tex' || $target eq 'analyze') {
+	my $code = @$parstack[$#$parstack];
+	if ($code) {
+	    $code =~ s/\"//g;
+	    $code .=';return $condition;';
+	    if (!$Apache::lonxml::default_homework_loaded) {
+		&Apache::lonxml::default_homework_load($safeeval);
+	    }
+	    $result = &Apache::run::run($code,$safeeval);
+	    &Apache::lonxml::debug("block :$code: returned :$result:");
+	} else {
+	    $result='1';
+	}
+	if ( ! $result ) {
+	    my $skip=&Apache::lonxml::get_all_text("/block",$$parser[-1]);
+	    &Apache::lonxml::debug("skipping ahead :$skip: $$parser[-1]");
+	}
+	$result='';
+    } elsif ($target eq 'edit') {
+	$result .=&Apache::edit::tag_start($target,$token);
+	$result .=&Apache::edit::text_arg('Test Condition:','condition',
+					  $token,40);
+	$result .=&Apache::edit::end_row().&Apache::edit::start_spanning_row();
+    } elsif ($target eq 'modified') {
+	my $constructtag=&Apache::edit::get_new_args($token,$parstack,
+						     $safeeval,'condition');
+	if ($constructtag) { $result = &Apache::edit::rebuild_tag($token); }
+    }
+    return $result;
+}
+
+sub end_block {
+  return '';
+}
+
+sub start_while {
+  my ($target,$token,$tagstack,$parstack,$parser,$safeeval)=@_;
 
   my $code = @$parstack[$#$parstack];
   $code =~ s/\"//g;
   $code .=';return $condition;';
-#  print "<br>$code<br>";
+
+  push( @Apache::structuretags::whileconds, $code); 
+  if (!$Apache::lonxml::default_homework_loaded) {
+      &Apache::lonxml::default_homework_load($safeeval);
+  }
   my $result = &Apache::run::run($code,$safeeval);
-  if ( ! $result ) { 
-#    my $skip=$$parser[$#$parser]->get_text("/block");
-    my $skip=&Apache::lonxml::get_all_text("block",$$parser[$#$parser]);
-#    print "skipped $skip";
+  my $bodytext=$$parser[$#$parser]->get_text("/while");
+  push( @Apache::structuretags::whilebody, $bodytext);
+  if ( $result ) { 
+    &Apache::lonxml::newparser($parser,\$bodytext);
   }
   return "";
 }
 
-sub end_block {
+sub end_while {
+  my ($target,$token,$tagstack,$parstack,$parser,$safeeval)=@_;
+  my $code = pop @Apache::structuretags::whileconds;
+  my $bodytext = pop @Apache::structuretags::whilebody;
+  my $result = &Apache::run::run($code,$safeeval);
+  if ( $result ) { 
+    &Apache::lonxml::newparser($parser,\$bodytext);
+  } 
+  return "";
+}
+
+# <randomlist show="1"> 
+#  <tag1>..</tag1>
+#  <tag2>..</tag2>
+#  <tag3>..</tag3>
+#  ... 
+# </randomlist>
+sub start_randomlist {
+  my ($target,$token,$tagstack,$parstack,$parser,$safeeval)=@_;
+  my $result;
+  if ($target eq 'answer' || $target eq 'grade' || $target eq 'web' ||
+      $target eq 'tex' || $target eq 'analyze') {
+    my $body= &Apache::lonxml::get_all_text("/randomlist",$$parser[$#$parser]);
+    my $b_parser= HTML::TokeParser->new(\$body);
+    my $b_tok;
+    my @randomlist;
+    my $list_item;
+    while($b_tok = $b_parser->get_token() ) {
+      if($b_tok->[0] eq 'S') { # start tag
+	# get content of the tag until matching end tag
+	# get all text upto the matching tag
+	# and push the content into @randomlist
+	$list_item = &Apache::lonxml::get_all_text('/'.$b_tok->[1],$b_parser);
+	$list_item = "$b_tok->[4]"."$list_item"."</$b_tok->[1]>";
+	push(@randomlist,$list_item);
+	#  print "<br /><b>START-TAG $b_tok->[1], $b_tok->[4], $list_item</b>";
+      }
+      if($b_tok->[0] eq 'T') { # text
+	# what to do with text in between tags?
+	#  print "<b>TEXT $b_tok->[1]</b><br />";
+      }
+      # if($b_tok->[0] eq 'E') { # end tag, should not happen
+      #  print "<b>END-TAG $b_tok->[1]</b><br />";
+      # }
+    }
+    my @idx_arr = (0 .. $#randomlist);
+    &Apache::structuretags::shuffle(\@idx_arr);
+    my $bodytext = '';
+    my $show=$#randomlist;
+    my $showarg=&Apache::lonxml::get_param('show',$parstack,$safeeval);
+    $showarg--;
+    if ( ($showarg >= 0) && ($showarg < $show) ) { $show = $showarg; }
+    for(0 .. $show) {
+      $bodytext .= "$randomlist[ $idx_arr[$_] ]";
+    }
+    &Apache::lonxml::newparser($parser,\$bodytext);
+  } elsif ($target eq 'edit' ) {
+    $result .= &Apache::edit::tag_start($target,$token);
+    $result .= &Apache::edit::text_arg('Maximum Tags to Show:','show',$token,5);
+    $result .= &Apache::edit::end_row().&Apache::edit::start_spanning_row();
+  } elsif ($target eq 'modified' ) {
+    my $constructtag=&Apache::edit::get_new_args($token,$parstack,$safeeval,
+						 'show');
+    if ($constructtag) { $result = &Apache::edit::rebuild_tag($token); }
+  }
+  return $result;
+}
+
+sub shuffle {
+    my $a=shift;
+    my $i;
+    if (defined(@$a)) {
+      &Apache::response::setrandomnumber();
+      for($i=@$a;--$i;) {
+	my $j=int(&Math::Random::random_uniform() * ($i+1));
+	next if $i == $j;
+	@$a[$i,$j] = @$a[$j,$i];
+      }
+    }
+}
+
+sub end_randomlist {
+  my ($target,$token,$tagstack,$parstack,$parser,$safeeval)=@_;
+  my $result;
+  if ($target eq 'edit' ) {
+    $result=&Apache::edit::tag_end($target,$token,'End Randomly Parsed Block');
+  }
+  return $result;
+}
+
+sub start_part {
+  my ($target,$token,$tagstack,$parstack,$parser,$safeeval)=@_;
+  my $result='';
+  my $id= &Apache::lonxml::get_param('id',$parstack,$safeeval);
+  if ($id eq '') { $id = $Apache::lonxml::curdepth; }
+  $Apache::inputtags::part=$id;
+  @Apache::inputtags::responselist = ();
+  @Apache::inputtags::previous=();
+  if ($target eq 'meta') {
+    return &Apache::response::mandatory_part_meta;
+  } elsif ($target eq 'web' || $target eq 'grade' || $target eq 'answer' || $target eq 'tex') {
+    my ($status,$accessmsg) = &Apache::lonhomework::check_access($id);
+    push (@Apache::inputtags::status,$status);
+    my $expression='$external::datestatus="'.$status.'";';
+    $expression.='$external::gradestatus="'.$Apache::lonhomework::history{"resource.$id.solved"}.'";';
+    &Apache::run::run($expression,$safeeval);
+    if ( $status eq 'CLOSED' ) {
+      my $bodytext=&Apache::lonxml::get_all_text("/part",$$parser[$#$parser]);
+      if ( $target eq "web" ) {
+	$result="<br />Part is not open to be viewed. It $accessmsg<br />";
+      } elsif ( $target eq 'tex' ) {
+	$result="\\end{minipage}\\vskip 0 mm Part is not open to be viewed. It $accessmsg \\\\\\begin{minipage}{\\textwidth}";
+      }
+    } else {
+      if ($target eq 'tex') {
+	if ($$tagstack[-2] ne 'problem') {
+	  $result.='\noindent \end{minipage}\vskip 0 mm \noindent \begin{minipage}{\textwidth}\noindent';
+	}
+      }
+    }
+  } elsif ($target eq 'edit') {
+      $result.=&Apache::edit::tag_start($target,$token);
+      $result.=&Apache::edit::text_arg('Part ID:','id',$token).
+	  &Apache::loncommon::help_open_topic("Part_Tag_Edit_Help").
+	      &Apache::edit::end_row().&Apache::edit::start_spanning_row();
+
+  } elsif ($target eq 'modified') {
+      my $constructtag=&Apache::edit::get_new_args($token,$parstack,$safeeval,
+						   'id');
+      if ($constructtag) {
+	  $result = &Apache::edit::rebuild_tag($token);
+	  $result.=&Apache::edit::handle_insert();
+      }
+  }
+  return $result;
+}
+
+sub end_part {
+  my ($target,$token,$tagstack,$parstack,$parser,$safeeval)=@_;
+  &Apache::lonxml::debug("in end_part $target ");
+  my $status=$Apache::inputtags::status['-1'];
+  my $result='';
+  if ( $target eq 'meta' ) {
+      $result='';
+  } elsif ( $target eq 'grade' && $status eq 'CAN_ANSWER') {
+    $result=&Apache::inputtags::grade;
+  } elsif ($target eq 'web' || $target eq 'tex' ) {
+    my $gradestatus=&Apache::inputtags::gradestatus($Apache::inputtags::part,
+						    $target);
+    if ($Apache::lonhomework::type eq 'exam') {$gradestatus='';}
+    $result=$gradestatus;
+  }
+  pop @Apache::inputtags::status;
+  return $result;
+}
+
+sub start_preduedate {
+  my ($target,$token,$tagstack,$parstack,$parser,$safeeval)=@_;
+  if ($target eq 'web' || $target eq 'grade' || $target eq 'answer' || $target eq 'tex') {
+    if ($Apache::inputtags::status['-1'] ne 'CAN_ANSWER' &&
+	$Apache::inputtags::status['-1'] ne 'CANNOT_ANSWER' && 
+        $Apache::inputtags::status['-1'] ne 'SHOW_ANSWER') {
+      &Apache::lonxml::get_all_text("/preduedate",$$parser[$#$parser]);
+    }
+  }
+  return '';
+}
+
+sub end_preduedate {
+  return '';
+}
+
+sub start_postanswerdate {
+  my ($target,$token,$tagstack,$parstack,$parser,$safeeval)=@_;
+  if ($target eq 'web' || $target eq 'grade' || $target eq 'tex') {
+    if ($Apache::inputtags::status['-1'] ne 'SHOW_ANSWER') {
+      &Apache::lonxml::get_all_text("/postanswerdate",$$parser[$#$parser]);
+    }
+  } elsif ($target eq 'tex') {
+      return '\vskip 0 mm \noindent';
+  }
+  return '';
+}
+
+sub end_postanswerdate {
+  return '';
+}
+
+sub start_notsolved {
+  my ($target,$token,$tagstack,$parstack,$parser,$safeeval)=@_;
+  if ($target eq 'web' || $target eq 'grade' || $target eq 'answer' || $target eq 'tex') {
+    my $gradestatus=$Apache::lonhomework::history{"resource.$Apache::inputtags::part.solved"};
+    &Apache::lonxml::debug("not solved has :$gradestatus:");
+    if ($gradestatus =~ /^correct/) {
+      &Apache::lonxml::debug("skipping");
+      &Apache::lonxml::get_all_text("/notsolved",$$parser[$#$parser]);
+    }
+  }
+  return '';
+}
+
+sub end_notsolved {
+  return '';
+}
+
+sub start_solved {
+  my ($target,$token,$tagstack,$parstack,$parser,$safeeval)=@_;
+  if ($target eq 'web' || $target eq 'grade' || $target eq 'answer' || $target eq 'tex') {
+    my $gradestatus=$Apache::lonhomework::history{"resource.$Apache::inputtags::part.solved"};
+    if ($gradestatus !~ /^correct/) {
+      &Apache::lonxml::get_all_text("/solved",$$parser[$#$parser]);
+    }
+  }
+  return '';
+}
+
+sub end_solved {
+  return '';
+}
+
+sub start_startouttext {
+  my ($target,$token,$tagstack,$parstack,$parser,$safeeval)=@_;
+  my @result=(''.'');
+  if ($target eq 'edit' || $target eq 'modified' ) { @result=('','no'); }
+  return (@result);
+}
+sub end_startouttext {
+  my ($target,$token,$tagstack,$parstack,$parser,$safeeval)=@_;
+  my $result='';
+  my $text='';
+
+  if ($target eq 'edit') {
+    $text=&Apache::lonxml::get_all_text("endouttext",$$parser[-1]);
+    $result.=&Apache::edit::start_table($token)."<tr><td>Text Block</td>
+<td>Delete:".
+  &Apache::edit::deletelist($target,$token)
+    ."</td>
+<td>".
+  &Apache::edit::insertlist($target,$token).
+    &Apache::edit::end_row().&Apache::edit::start_spanning_row()."\n".
+      &Apache::edit::editfield($token->[1],$text,"",80,4);
+  }
+  if ($target eq 'modified') {
+    $text=&Apache::lonxml::get_all_text("endouttext",$$parser['-1']);
+    $result='<startouttext />'.&Apache::edit::modifiedfield();
+  }
+  if ($target eq 'tex') {
+      $result .= '\noindent ';
+  }
+  return $result;
+}
+sub start_endouttext {
+  my ($target,$token,$tagstack,$parstack,$parser,$safeeval)=@_;
+  my $result='';
+  if ($target eq "edit" ) { $result="</td></tr>".&Apache::edit::end_table()."\n"; }
+  if ($target eq "modified") { 
+     $result='<endouttext />'.
+     &Apache::edit::handle_insertafter('startouttext'); }
+  return $result;
+}
+sub end_endouttext {
+  my ($target,$token,$tagstack,$parstack,$parser,$safeeval)=@_;
+  my @result=('','');
+  if ($target eq "edit" || $target eq 'modified') { @result=('','no'); }
+  return (@result);
+}
+sub delete_startouttext {
+  my ($target,$token,$tagstack,$parstack,$parser,$safeeval)=@_;
+#  my $text=&Apache::lonxml::get_all_text("endouttext",$$parser['-1']);
+  my $text=$$parser['-1']->get_text("/endouttext");
+  my $ntoken=$$parser['-1']->get_token();
+  &Apache::lonxml::debug("Deleting :$text: and :$ntoken->[0]:$ntoken->[1]:$ntoken->[2]: for startouttext");
+  &Apache::lonxml::end_tag($tagstack,$parstack,$ntoken);
+  # Deleting 2 parallel tag pairs, but we need the numbers later to look like 
+  # they did the last time round
+  &Apache::lonxml::increasedepth($ntoken);
+  &Apache::lonxml::decreasedepth($ntoken);
+  return 1;
 }
 
 1;
