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- shortened parser by splitting out "recursion" sections

    1: # The LearningOnline Network with CAPA
    2: # XML Parser Module 
    3: #
    4: # last modified 06/26/00 by Alexander Sakharuk
    5: 
    6: package Apache::lonxml; 
    7: 
    8: use strict;
    9: use HTML::TokeParser;
   10: use Safe;
   11: use Opcode;
   12: 
   13: sub register {
   14:   my $space;
   15:   my @taglist;
   16:   my $temptag;
   17:   ($space,@taglist) = @_;
   18:   foreach $temptag (@taglist) {
   19:     $Apache::lonxml::alltags{$temptag}=$space;
   20:   }
   21: }
   22:                                      
   23: use Apache::style;
   24: use Apache::lontexconvert;
   25: use Apache::run;
   26: use Apache::londefdef;
   27: use Apache::scripttag;
   28: #==================================================   Main subroutine: xmlparse  
   29: 
   30: sub xmlparse {
   31: 
   32:  my ($target,$content_file_string,%style_for_target) = @_;
   33:  my $pars = HTML::TokeParser->new(\$content_file_string);
   34:  my $currentstring = '';
   35:  my $finaloutput = ''; 
   36:  my $newarg = '';
   37:  my $safeeval = new Safe;
   38:  $safeeval->permit("entereval");
   39:  $safeeval->permit(":base_math");
   40: #-------------------- Redefinition of the target in the case of compound target
   41: 
   42:  ($target, my @tenta) = split('&&',$target);
   43: 
   44: #------------------------- Stack definition (in stack we have all current tags)
   45: 
   46:  my @stack = (); 
   47:  my @parstack = ();
   48: 
   49: #------------------------------------- Parse input string (content_file_string)
   50:  
   51:  my $token;
   52:  
   53:  while ($token = $pars->get_token) {
   54:    if ($token->[0] eq 'T') {
   55:      $finaloutput .= &Apache::run::evaluate($token->[1],$safeeval,'');
   56:    } elsif ($token->[0] eq 'S') {
   57:      # add tag to stack 	    
   58:      push (@stack,$token->[1]);
   59:      # add parameters list to another stack
   60:      push (@parstack,&parstring($token));
   61:      
   62:      if (exists $style_for_target{$token->[1]}) {
   63:        $finaloutput .= &recurse($style_for_target{$token->[1]},
   64: 				$target,$safeeval,\%style_for_target,
   65: 				@parstack);
   66:      } else {
   67:        my $result = &callsub("start_$token->[1]", $target, $token,\@parstack,
   68: 			     $pars, $safeeval, \%style_for_target);
   69:        if ($result ne "" ) {
   70: 	 $finaloutput .= &Apache::run::evaluate($result,$safeeval,
   71: 						$parstack[$#parstack]);
   72:        }
   73:      }              
   74:    } elsif ($token->[0] eq 'E')  {
   75:      #clear out any tags that didn't end
   76:      while ($token->[1] ne $stack[$#stack] 
   77: 	    && ($#stack > 0)) {pop @stack;pop @parstack;}
   78: 
   79:      if (exists $style_for_target{'/'."$token->[1]"}) {
   80:        $finaloutput .= &recurse($style_for_target{'/'."$token->[1]"},
   81: 			       $target,$safeeval,\%style_for_target,
   82: 				@parstack);
   83:      } else {
   84:        my $result = &callsub("end_$token->[1]", $target, $token, \@parstack,
   85: 			     $pars,$safeeval, \%style_for_target);
   86:        if ($result ne "") {
   87: 	 $finaloutput .= &Apache::run::evaluate($result,$safeeval,
   88: 						$parstack[$#parstack]);
   89:        }
   90:      }
   91:      pop @stack; 
   92:      pop @parstack;
   93:    }
   94:  }
   95:  return $finaloutput;
   96: }
   97: 
   98: sub recurse {
   99:   
  100:   my @innerstack = (); 
  101:   my @innerparstack = ();
  102:   my ($newarg,$target,$safeeval,$style_for_target,@parstack) = @_;
  103:   my $pat = HTML::TokeParser->new(\$newarg);
  104:   my $tokenpat;
  105:   my $partstring = '';
  106:   my $output='';
  107:   while  ($tokenpat = $pat->get_token) {
  108:     if ($tokenpat->[0] eq 'T') {
  109:       $partstring = $tokenpat->[1];
  110:     } elsif ($tokenpat->[0] eq 'S') {
  111:       push (@innerstack,$tokenpat->[1]);
  112:       push (@innerparstack,&parstring($tokenpat));
  113:       $partstring = &callsub("start_$tokenpat->[1]", 
  114: 			     $target, $tokenpat, \@innerparstack,
  115: 			     $pat, $safeeval, $style_for_target);
  116:     } elsif ($tokenpat->[0] eq 'E') {
  117:       #clear out any tags that didn't end
  118:       while ($tokenpat->[1] ne $innerstack[$#innerstack] 
  119: 	     && ($#innerstack > 0)) {pop @innerstack;pop @innerparstack;}
  120:       $partstring = &callsub("end_$tokenpat->[1]",
  121: 			     $target, $tokenpat, \@innerparstack,
  122: 			     $pat, $safeeval, $style_for_target);
  123:     }
  124:     #pass both the variable to the style tag, and the tag we 
  125:     #are processing inside the <definedtag>
  126:     if ( $partstring ne "" ) {
  127:       $output .= &Apache::run::evaluate($partstring,$safeeval,
  128:                   $parstack[$#parstack].$innerparstack[$#innerparstack]);
  129:     }
  130:     if ($tokenpat->[0] eq 'E') { pop @innerstack;pop @innerparstack; }
  131:   }
  132:   return $output;
  133: }
  134: 
  135: sub callsub {
  136:   my ($sub,$target,$token,$parstack,$parser,$safeeval,$style)=@_;
  137:   my $currentstring='';
  138:   {
  139:     no strict 'refs';
  140:     if (my $space=$Apache::lonxml::alltags{$token->[1]}) {
  141:       #print "Calling sub $sub in $space \n";
  142:       $sub="$space\:\:$sub";
  143:       $currentstring = &$sub($target,$token,\@$parstack,$parser,$safeeval,$style);
  144:     } else {
  145:       #print "NOT Calling sub $sub\n";
  146:       if (defined($token->[4])) {
  147: 	$currentstring = $token->[4];
  148:       } else {
  149: 	$currentstring = $token->[2];
  150:       }
  151:     }
  152:     use strict 'refs';
  153:   }
  154:   return $currentstring;
  155: }
  156: 
  157: sub parstring {
  158:   my ($token) = @_;
  159:   my $temp='';
  160:   map {$temp .= "my \$$_=\"$token->[2]->{$_}\";"} @{$token->[3]};
  161:   return $temp;
  162: }
  163: 1;
  164: __END__
  165: 
  166: 
  167: 
  168: 
  169: