File:  [LON-CAPA] / loncom / homework / structuretags.pm
Revision 1.152: download - view: text, annotated - select for diffs
Mon Mar 3 15:59:42 2003 UTC (21 years, 1 month ago) by www
Branches: MAIN
CVS tags: HEAD
Menubuttons "Forward", "Backward", etc, on top of homework

# The LearningOnline Network with CAPA 
# definition of tags that give a structure to a document
#
# $Id: structuretags.pm,v 1.152 2003/03/03 15:59:42 www 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','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);
  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);
  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);
    $head_tag_start='<head>'.&Apache::lonmenu::registerurl(undef,$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)=&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 $name=&Apache::lonnet::gettitle();
  if ($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);
    return '';
  }
#intialize globals
  $Apache::inputtags::part='0';
  @Apache::inputtags::responselist = ();
  @Apache::inputtags::previous=();
  $Apache::structuretags::printanswer='No';
  if ($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 $weight = &Apache::lonnet::EXT("resource.$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 $due_file_content;
        if ($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') {
		    $result .= '\begin{document} \noindent\textit{Due date: '.$duedate.'} \vskip 1 mm\noindent \begin{minipage}{\textwidth}';	
		} else {
		    $result .= '\begin{document} \noindent \vskip 1 mm \noindent\begin{minipage}{\textwidth}';
		    if ($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_/) {
		$result .= '\begin{document} \noindent \vskip 1 mm\noindent\begin{minipage}{\textwidth}';	
		if (($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,$target);
      if ($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();
    }
    if ($target eq 'answer' && ($ENV{'request.state'} eq 'construct') ) {
	$result.='</html>'; #normally we get it from xmlend, but in CSTR
                            # we always show answer mode too.
    }
  } elsif ($target eq 'meta') {
    if ($Apache::inputtags::part eq '0') {
      $result=&Apache::response::mandatory_part_meta;
    }
  } elsif ($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,$tagstack,$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);
	    &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;';

  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=$$parser[$#$parser]->get_text("/while");
  push( @Apache::structuretags::whilebody, $bodytext);
  if ( $result ) { 
    &Apache::lonxml::newparser($parser,\$bodytext);
  }
  return "";
}

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);
    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=();
  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;
  }
  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);
    }
  }
  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"
	.'<table><tr><td>'.
    &Apache::loncommon::help_open_topic("Greek_Symbols",'Greek Symbols',
					undef,undef,600)
	.'</td><td>'.
    &Apache::loncommon::help_open_topic("Other_Symbols",'Other Symbols',
					undef,undef,600)
	.'</td></tr></table>'.
    &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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