package Apache::run;

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

1;
__END__;