package Apache::run;
#
# $Id: run.pm,v 1.26 2002/04/10 15:22:02 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/
#

use HTML::Entities;

$Apache::run::EVALUATE_STRING=<<'ENDEVALUATE';  
  my %_LONCAPA_INTERNAL_oldexpressions=();
  my $i=0;
  while (!$_LONCAPA_INTERNAL_oldexpressions{$_}) {
    $_LONCAPA_INTERNAL_oldexpressions{$_}=1;
    $_ =~s/((?:\$|\&)(?:[\#|\$]*[A-Za-z][\w]*|\{[A-Za-z][\w]*\}))([\[\{][^\$\&\]\}]+[\]\}])*?(\([^\$\&\)]+\))*?(?=[^\[\{\(]|$)/eval(defined(eval($1.$2))?eval('$1.$2.$3'):'$1.$2.$3')/seg;
    if ($i++ > 10 ) { last; }
  }
ENDEVALUATE

sub evaluate {
  my ($expression,$safeeval,$decls) = @_;
  unless (defined($expression)) { return ''; }
  if (!$Apache::lonxml::evaluate) { return $expression; }
  my $result = '';
  $@='';
  $safeeval->reval('{'.$decls.';$_=<<\'EXPRESSION\';'."\n".$expression.
		   "\n".'EXPRESSION'."\n".$EVALUATE_STRING.'}');
#  $safeeval->reval('{'.$decls.';<< &evaluate(q|'.$expression.'|);}');
  my $error=$@;
  if ($@ eq '') {
    $result = $safeeval->reval('return $_;');
    chomp $result;
  } else {
    &Apache::lonxml::error('substitution on <pre>'.$expression.
			   '</pre> with <pre>'.$decls.
			   '</pre> caused <pre>'.$error);
  }  
  return $result
}

sub run {
  my ($code,$safeeval,$hideerrors) = @_;
#  print "inside run\n";
  $@='';
  my (@result)=$safeeval->reval($code);
  my $error=$@;
  if ($error ne '' && !$hideerrors) {
    &Apache::lonxml::error('<pre>'.&HTML::Entities::encode($error).
			   '</pre> occured while running <pre>'.
			   &HTML::Entities::encode($code).'</pre>');
  }
  if ( $#result < '1') {
    return $result[0];
  } else {
    &Apache::lonxml::debug("<b>Got lots results</b>:$#result:");
    return (@result);
  }
}

sub dump {
  my ($target,$safeeval)=@_;
  my $dump='';
  foreach my $symname (sort keys %{$safeeval->varglob('main::')}) {
    if (($symname!~/^\_/) && ($symname!~/\:$/)) {
      if ($safeeval->reval('defined($'.$symname.')')) {
	$dump.='$'.$symname.'='.$safeeval->reval('$'.$symname)."\n";
      }	
      if ($safeeval->reval('defined(@'.$symname.')')) {
	$dump.='@'.$symname.'=('.
	  $safeeval->reval('join(",",@'.$symname.')').")\n";
      }
      if ($safeeval->reval('defined(%'.$symname.')')) {
	$dump.='%'.$symname.'=(';
	$dump.=$safeeval->reval('join(",",map { $_."=>".$'.
				$symname.'{$_} } sort keys %'.
				$symname.')').")\n";
      }
    }
  }
  $dump.='';
  return $dump;
}

1;
__END__;