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GPL

package Apache::run;
#
# $Id: run.pm,v 1.21 2001/11/29 19:03:58 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/
#

sub evaluateold {
  my ($expression,$safeeval,$decls) = @_;
# print "inside2 evaluate $decls with $expression<br />\n";
# gerd's old method interpolates unset vars
# $safeeval->reval('return qq('.$expression.');');
  unless (defined $expression) { return ''; }
  my $result = '';
  $@='';
  $safeeval->reval('$_=q|'.$expression.'|;');
  if ($@ eq '') {
    $safeeval->reval('{'.$decls.'$_=~s/(\$[A-Za-z]\w*)/(defined(eval($1))?eval($1):$1)/ge;}');
    if ($@ eq '') {
      $result = $safeeval->reval('return $_;');
    } else {
      &Apache::lonxml::error("substitution on:$expression:with:$decls:caused");
    }
  } else {
    &Apache::lonxml::error("defining:$expression:caused");
  }
  if ($@ ne '') {&Apache::lonxml::error($@);}
  return $result
}

$Apache::run::EVALUATE_STRING=<<'ENDEVALUATE';  
  my %oldexpressions=();
  while (!$oldexpressions{$_}) {
    $oldexpressions{$_}=1;
    $_ =~s/((?:\$|\&)(?:[\#|\$]*[A-Za-z][\w]*|\{[A-Za-z][\w]*\}))([\[\{][^\$\&\]\}]+[\]\}])*?(\([^\$\&\)]+\))*?(?=[^\[\{\(]|$)/eval(defined(eval($1.$2))?eval('$1.$2.$3'):'$1.$2.$3')/seg;
  }
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|'.$expression.'|);}');
  if ($@ eq '') {
    $result = $safeeval->reval('return $_;');
    chomp $result;
  } else {
    &Apache::lonxml::error("substitution on:$expression:with:$decls:caused $@");
  }  
  return $result
}

sub run {
  my ($code,$safeeval,$hideerrors) = @_;
#  print "inside run\n";
  $@='';
  my (@result)=$safeeval->reval($code);
  if ($@ ne '' && !$hideerrors) {
    &Apache::lonxml::error(":$code:caused");
    &Apache::lonxml::error($@);
  }
  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__;