File:  [LON-CAPA] / loncom / homework / structuretags.pm
Revision 1.188: download - view: text, annotated - select for diffs
Fri Jun 20 14:45:19 2003 UTC (20 years, 9 months ago) by bowersj2
Branches: MAIN
CVS tags: HEAD
Use Apache::loncommon::helpLatexCheatSheet instead of constructing it
manually.

# The LearningOnline Network with CAPA 
# definition of tags that give a structure to a document
#
# $Id: structuretags.pm,v 1.188 2003/06/20 14:45:19 bowersj2 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();
use Apache::lonmenu;

BEGIN {
    &Apache::lonxml::register('Apache::structuretags',('block','languageblock','instructorcomment','while','randomlist','problem','library','web','tex','part','preduedate','postanswerdate','solved','notsolved','startouttext','endouttext'));
}

sub start_web {
    my ($target,$token,$tagstack,$parstack,$parser,$safeeval)=@_;
    if (!($target eq 'web' || $target eq 'edit' || $target eq 'modified' ||
	  $target eq 'answer' || $target eq 'grade' || $target eq 'meta' )) {
	my $bodytext=&Apache::lonxml::get_all_text("/web",$parser);
    }
    return '';
}

sub end_web {
    return '';
}

sub start_tex {
    my ($target,$token,$tagstack,$parstack,$parser,$safeeval)=@_;
    if (!($target eq 'tex' || $target eq 'edit' || $target eq 'modified' ||
	  $target eq 'answer' || $target eq 'grade' || $target eq 'meta' )) {
	&Apache::lonxml::debug("tex 1");
	my $bodytext=&Apache::lonxml::get_all_text("/tex",$parser);
    }
    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);
	$head_tag_start='<head>'.&Apache::lonmenu::registerurl(undef,$target);
    }
    my $body_tag_start;
    if (!defined($found{'body'})) {
	$body_tag_start='<body onLoad="'.&Apache::lonmenu::loadevents().'" '.
	    'onUnload="'.&Apache::lonmenu::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"';
	    }
	}
	$body_tag_start.='>'.&Apache::lonmenu::menubuttons(undef,$target,1);
	if ($target eq 'web' && $ENV{'request.state'} ne 'construct') {
	    my ($symb,undef,undef,undef,$publicuser)=
		&Apache::lonxml::whichuser();
	    if ($symb eq '' && !$publicuser) {
		my $help = &Apache::loncommon::help_open_topic("Ambiguous_Reference");
		$help="Browsing resource, all submissions are temporary.<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 $name=&Apache::lonnet::gettitle();
    if ($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 $rndseed;
    my ($symb)=&Apache::lonxml::whichuser();
    if ($ENV{'request.state'} eq "construct" || $symb eq '') {
	$rndseed=$ENV{'form.rndseed'};
	if (!$rndseed) {
	    $rndseed=$Apache::lonhomework::history{'rndseed'};
	    if (!$rndseed) {
		$rndseed=time;
		$ENV{'form.rndseed'}=$rndseed;
	    }
	}
	if ($ENV{'form.resetdata'} eq 'New Problem Variation' ||
	    $ENV{'form.newrandomization'} eq 'New Randomization') {
	    $rndseed=time;
	    if ($rndseed eq $ENV{'form.rndseed'}) {
		srand($rndseed);
		$rndseed=int(rand(1000000000));
	    }
	    $ENV{'form.rndseed'}=$rndseed;
	    delete($ENV{'form.resetdata'});
	    delete($ENV{'form.newrandomization'});
	}
	if (defined($rndseed) && $rndseed ne int($rndseed)) {
	   $rndseed=join(',',&Math::Random::random_seed_from_phrase($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" />
             <input type="submit" name="newrandomization" value="New Randomization" />
             <input type="submit" name="resetdata" value="Reset Submissions" />
             <nobr><input type="submit" name="changerandseed" value="Change Random Seed To:" />
              <input type="text" name="rndseed" width="10" value="'.
	       $rndseed.'"
           onChange="javascript:document.lonhomework.changerandseed.click()" /></nobr>
             <input type="checkbox" name="showallfoils" ';
    if (defined($ENV{'form.showallfoils'})) { $result.='checked="on"'; }
    $result.= ' />&nbsp;Show&nbsp;All&nbsp;Foils
             <hr />';
    my $numtoanalyze=$ENV{'form.numtoanalyze'};
    if (!$numtoanalyze) { $numtoanalyze=20; }
    $result.= '<input type="submit" name="problemmode" value="Calculate answers" /> for
             <input type="text" name="numtoanalyze" value="'.
		 $numtoanalyze.'" size="5" /> versions of this problem.'.
		     &Apache::loncommon::help_open_topic("Analyze_Problem",
						     '',undef,undef,300).
		     '<hr />';
    return $result;
}

sub initialize_storage {
    %Apache::lonhomework::results=();
    %Apache::lonhomework::history=();
    my ($symb,$courseid,$domain,$name) = &Apache::lonxml::whichuser();
    if ($ENV{'request.state'} eq 'construct' || $symb eq '') {
	%Apache::lonhomework::history=
	    &Apache::lonnet::tmprestore($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' || $symb eq '') {
	    $Apache::lonhomework::results{'rndseed'}=$ENV{'form.rndseed'};
	    $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)=@_;

    if ( $Apache::inputtags::part ne '' ||
	 $Apache::lonhomework::parsing_a_problem) {
	&Apache::lonxml::error('Only one &lt;problem&gt; allowed in a .problem file');
	#my $bodytext=&Apache::lonxml::get_all_text("/problem",$parser);
	return '';
    }

    $Apache::lonhomework::parsing_a_problem=1;
#initialize globals
    $Apache::inputtags::part='0';
    @Apache::inputtags::partlist=('0');
    @Apache::inputtags::responselist = ();
    @Apache::inputtags::importlist = ();
    @Apache::inputtags::previous=();
    @Apache::inputtags::previous_version=();
    $Apache::structuretags::printanswer='No';
    @Apache::structuretags::whileconds=();
    @Apache::structuretags::whilebody=();
    @Apache::structuretags::whileline=();
    $Apache::lonhomework::scantronmode=0;
    $Apache::lonhomework::problemstatus=
	&Apache::lonnet::EXT('resource.0.problemstatus');

    if (defined($ENV{'scantron.maxquest'})) {
	$Apache::lonhomework::scantronmode=1;
    }

    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);
	my ($symb)=&Apache::lonxml::whichuser();
	if ($ENV{'request.state'} ne "construct" && $symb eq '') {
	    $form_tag_start.='<input type="hidden" name="rndseed" value="'.
		$rndseed.'" />'.
		    '<input type="submit" name="resetdata"
                             value="New Problem Variation" />'.
		    '<input type="hidden" name="username"
                             value="'.$ENV{'form.username'}.'" /> <br />';
	}
	($status,$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") {
		    $result.= &problem_web_to_edit_header($ENV{'form.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 $startminipage = '';
	    if ($ENV{'form.problem_split'} ne 'yes') {
		$startminipage = '\begin{minipage}{\textwidth}';
	    }
	    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 $weight = &Apache::lonnet::EXT("resource.$id.weight");
	    my $allkeys=&Apache::lonnet::metadata($ENV{'request.uri'},'keys');
	    my @allkeys = split /,/,$allkeys;
	    my $allow_print_points = 0;
	    foreach my $partial_key (@allkeys) {
		if ($partial_key=~m/weight/) {
		    $allow_print_points++;
		}
	    }
	    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;
	    my $name_of_resourse= &get_resource_name($parstack,$safeeval);
	    if ($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/ and $Apache::lonhomework::type ne 'exam') {
			$result .= '\begin{document} \typeout{STAMPOFPASSEDRESOURCESTART Resource <h2>"'.$name_of_resourse.'"</h2> located in <br /><small><b>'.$ENV{'request.uri'}.'</b></small><br /> STAMPOFPASSEDRESOURCEEND} \noindent\textit{Due date: '.$duedate.'} \vskip 1 mm\noindent '.$startminipage;	
		    } else {
			$result .= '\begin{document} \typeout{STAMPOFPASSEDRESOURCESTART Resource <h2>"'.$name_of_resourse.'"</h2> located in <br /><small><b>'.$ENV{'request.uri'}.'</b></small><br /> STAMPOFPASSEDRESOURCEEND} \noindent \vskip 1 mm \noindent'.$startminipage;
			if ($Apache::lonhomework::type eq 'exam' and $allow_print_points==1) { $result .= '\fbox{\textit{'.$weight.' pt}}';}
		    }
		} else {
		    $result .= '\vskip 1mm\textit{Due date: '.$duedate.'} \\\\\\\\';
		}
	    } else {
		if (not $ENV{'request.symb'} =~ m/\.page_/) {
		    $result .= '\begin{document} \typeout{STAMPOFPASSEDRESOURCESTART Resource <h2>"'.$name_of_resourse.'"</h2> located in <br /><small><b>'.$ENV{'request.uri'}.'</b></small><br /> STAMPOFPASSEDRESOURCEEND} \noindent \vskip 1 mm\noindent'.$startminipage;	
		    if (($Apache::lonhomework::type eq 'exam') and ($allow_print_points==1)) { $result .= '\fbox{\textit{'.$weight.' pt}}';}
		} 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' &&
	     $status eq 'CAN_ANSWER' ) {
	    # if part is zero, no <part>s existed, so we need to the grading
	    &Apache::inputtags::grade;
	} elsif ( ($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);
	    $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' &&
		    $ENV{'form.answer_output_mode'} 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') {
		my $endminipage = '';
		if ($ENV{'form.problem_split'} ne 'yes') {
		    $endminipage = '\end{minipage}';
		}
		$result .= '\keephidden{ENDOFPROBLEM}\vskip 0.5mm\noindent\makebox[\textwidth/$number_of_columns][b]{\hrulefill}';
		if (not $ENV{'request.symb'} =~ m/\.page_/) {
		    $result .= $endminipage.'\end{document} ';
		} else {
		    $result .= '';
		}
	    }
	}
	if ($target eq 'grade') {
	    &Apache::lonhomework::showhash(%Apache::lonhomework::results);
	    &finalize_storage();
	}
	if ($target eq 'answer' && ($ENV{'request.state'} eq 'construct')
	    && $ENV{'form.answer_output_mode'} ne 'tex') {
	    $result.='</html>'; # normally we get it from xmlend, but in CSTR
	                        # we always show answer mode too.
	}
    } elsif ($target eq 'meta') {
	if ($Apache::inputtags::part eq '0') {
	    @Apache::inputtags::response=();
	    $result=&Apache::response::mandatory_part_meta;
	}
    } elsif ($target eq 'edit') {
	&Apache::lonxml::debug("in end_problem with $target, edit");
	$result = &problem_edit_footer();
    }

    if ($ENV{'request.state'} eq 'construct' && $target eq 'web') {
	&Apache::inputtags::check_for_duplicate_ids();
    }
    undef(%Apache::lonhomework::history);
    undef(%Apache::lonhomework::results);
    undef($Apache::inputtags::part);
    undef($Apache::lonhomework::parsing_a_problem);

    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,$tagstack,$parstack,$parser,$safeeval)=@_;

    my $result;

    if ($target eq 'web' || $target eq 'grade' || $target eq 'answer' ||
	$target eq 'tex' || $target eq 'analyze') {
	my $code = $token->[2]->{'condition'};
	if ($code) {
	    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);
	    &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 {
    my ($target,$token,$tagstack,$parstack,$parser,$safeeval)=@_;
    my $result;
    if ($target eq "edit") {
	$result.= &Apache::edit::tag_end($target,$token,'');
    }
    return $result;
}

sub start_languageblock {
    my ($target,$token,$tagstack,$parstack,$parser,$safeeval)=@_;

    my $result;

    if ($target eq 'web' || $target eq 'grade' || $target eq 'answer' ||
	$target eq 'tex' || $target eq 'analyze') {
	&Apache::lonxml::startredirection();
    } elsif ($target eq 'edit') {
	$result .=&Apache::edit::tag_start($target,$token);
	$result .=&Apache::edit::text_arg('Include Language:','include',
					  $token,40);
	$result .=&Apache::edit::text_arg('Exclude Language:','exclude',
					  $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,
						     $safeeval,'include',
						     'exclude');
	if ($constructtag) { $result = &Apache::edit::rebuild_tag($token); }
    }
    return $result;
}

sub end_languageblock {
    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 $text=&Apache::lonxml::endredirection();
	my $include= &Apache::lonxml::get_param('include',$parstack,$safeeval);
	my $exclude= &Apache::lonxml::get_param('exclude',$parstack,$safeeval);
	my %languages=&Apache::loncommon::display_languages();
	$result='1';
	if ($include) {
	    $result='';
	    foreach (split(/\,/,$include)) {
		if ($languages{$_}) { $result='1'; }
	    }
	}
	if ($exclude) {
	    foreach (split(/\,/,$exclude)) {
		if ($languages{$_}) { $result='0'; }
	    }
	}
	if ( ! $result ) {
	    $result='';
	} else {
	    $result=$text;
	}
    } elsif ($target eq "edit") {
	$result.= &Apache::edit::tag_end($target,$token,'');
    }
    return $result;
}

sub start_instructorcomment {
    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') {
        $result=($ENV{'request.role'}=~/^(in|cc|au|ca|li)/);
	if ( ! $result ) {
	    my $skip=&Apache::lonxml::get_all_text("/instructorcomment",$parser);
	    &Apache::lonxml::debug("skipping ahead :$skip: $$parser[-1]");
	}
	$result='';
    } elsif ($target eq 'edit') {
	$result .=&Apache::edit::tag_start($target,$token);
	$result .=&Apache::edit::end_row().&Apache::edit::start_spanning_row();
    }
    return $result;
}

sub end_instructorcomment {
    my ($target,$token,$tagstack,$parstack,$parser,$safeeval)=@_;
    my $result;
    if ($target eq "edit") {
	$result.= &Apache::edit::tag_end($target,$token,'');
    }
    return $result;
}

sub start_while {
    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 = $token->[2]->{'condition'};

	push( @Apache::structuretags::whileconds, $code);
	if (!$Apache::lonxml::default_homework_loaded) {
	    &Apache::lonxml::default_homework_load($safeeval);
	}
	my $result = &Apache::run::run($code,$safeeval);
	my $bodytext=&Apache::lonxml::get_all_text("/while",$parser);
	push( @Apache::structuretags::whilebody, $bodytext);
	push( @Apache::structuretags::whileline, $token->[5]);
	&Apache::lonxml::debug("s code $code got -$result-");
	if ( $result ) {
	    &Apache::lonxml::newparser($parser,\$bodytext);
	}
    } 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_while {
    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 = pop(@Apache::structuretags::whileconds);
	my $bodytext = pop(@Apache::structuretags::whilebody);
	my $line = pop(@Apache::structuretags::whileline);
	my $return = &Apache::run::run($code,$safeeval);
	my $starttime=time;
	my $error=0;
	while ($return) {
	    if (time-$starttime >
		$Apache::lonnet::perlvar{'lonScriptTimeout'}) {
		$return = 0; $error=1; next;
	    }
	    $result.=&Apache::scripttag::xmlparse($bodytext);
	    $return = &Apache::run::run($code,$safeeval);
	}
	if ($error) {
	    &Apache::lonxml::error('<pre>Code ran too long. It ran for more than '.$Apache::lonnet::perlvar{'lonScriptTimeout'}.' seconds occured while running &lt;while$gt; on line '.$line.'</pre>');
	}
    } elsif ($target eq "edit") {
	$result.= &Apache::edit::tag_end($target,$token,'');
    }
    return $result;
}

# <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);
	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;
    push(@Apache::inputtags::partlist,$id);
    @Apache::inputtags::response=();
    @Apache::inputtags::previous=();
    @Apache::inputtags::previous_version=();
    $Apache::lonhomework::problemstatus=
	&Apache::lonnet::EXT("resource.$id.problemstatus");
    my $hidden=&Apache::loncommon::check_if_partid_hidden($Apache::inputtags::part);

    if ($target eq 'meta') {
	return &Apache::response::mandatory_part_meta;
    } elsif ($target eq 'web' || $target eq 'grade' ||
	     $target eq 'answer' || $target eq 'tex') {
	if ($hidden) {
	    my $bodytext=&Apache::lonxml::get_all_text("/part",$parser);
	} else {
	    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);
		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') {
		    $result.='\noindent \end{minipage}\vskip 0 mm \noindent \begin{minipage}{\textwidth}\noindent';
		    my $weight = &Apache::lonnet::EXT("resource.$id.weight");
		    if ($Apache::lonhomework::type eq 'exam') { $result .= '\fbox{\textit{'.$weight.' pt}}';}
		}
	    }
	}
    } 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 $hidden=&Apache::loncommon::check_if_partid_hidden($Apache::inputtags::part);
    my $result='';
    if ( $target eq 'meta' ) {
	$result='';
    } elsif ( $target eq 'grade' && $status eq 'CAN_ANSWER' && !$hidden) {
	$result=&Apache::inputtags::grade;
    } elsif (($target eq 'web' || $target eq 'tex') && !$hidden ) {
	my $gradestatus=&Apache::inputtags::gradestatus($Apache::inputtags::part,
							$target);
	if ($Apache::lonhomework::type eq 'exam') {$gradestatus='';}
	$result=$gradestatus;
    } elsif ($target eq 'edit') {
	$result=&Apache::edit::end_table();
    }
    pop @Apache::inputtags::status;
    $Apache::inputtags::part='';
    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);
	}
    }
    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",$parser);
	}
    } elsif ($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);
	}
    }
    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);
	}
    }
    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);
	$result.=&Apache::edit::start_table($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::loncommon::helpLatexCheatsheet () .
		 &Apache::edit::editfield($token->[1],$text,"",80,4);
    }
    if ($target eq 'modified') {
	$text=&Apache::lonxml::get_all_text("endouttext",$parser);
	$result='<startouttext />'.&Apache::edit::modifiedfield();
    }
    if ($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);
    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;
__END__

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