--- loncom/homework/default_homework.lcpm	2011/06/07 22:07:09	1.156
+++ loncom/homework/default_homework.lcpm	2011/06/08 01:39:28	1.157
@@ -1,7 +1,7 @@
 # The LearningOnline Network with CAPA 
 # used by lonxml::xmlparse() as input variable $safeinit to Apache::run::run()
 #
-# $Id: default_homework.lcpm,v 1.156 2011/06/07 22:07:09 www Exp $
+# $Id: default_homework.lcpm,v 1.157 2011/06/08 01:39:28 www Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -270,7 +270,10 @@ sub caparesponse_check_list {
     my $type = $LONCAPA::CAPAresponse_args{'type'};
     my $answerunit=$LONCAPA::CAPAresponse_args{'unit'};
     &LONCAPA_INTERNAL_DEBUG("Got type :$type: answer unit :$answerunit:\n");
-    
+   
+    my $preprocess=$LONCAPA::CAPAresponse_args{'preprocess'};
+    $preprocess=~s/^\&//;
+
     my $num_input_lines =
 	scalar(@{$LONCAPA::CAPAresponse_answer->{'answers'}});
     
@@ -319,7 +322,7 @@ sub caparesponse_check_list {
         } else {
            ($part1,$part2)=($responses->[0][-1]=~ /^([\d\.\,\s\$]*(?:(?:[xX\*]10[\^\*]*|[eE]*)[\+\-]*\d*)*(?:^|\S)\d+)([\$\s\w\^\*\/\(\)\+\-]*[^\d\.\s\,][\$\s\w\^\*\/\(\)\+\-]*)$/);
         }
-        if ($part1 && $part2) {
+        if (defined($part1) && defined($part2)) {
 	    $responses->[0][-1]=$part1;
 	    $unit=&capa_formula_fix($part2);
             &LONCAPA_INTERNAL_DEBUG("Found unit :$unit:");
@@ -329,7 +332,15 @@ sub caparesponse_check_list {
     $unit=~s/\s//;
     my $error;
     foreach my $response (@$responses) {
-       foreach my $element (@$response) {	
+       foreach my $element (@$response) {
+          # See if we have preprocessor
+          if ($preprocess=~/\S/) {
+             if (defined(&$preprocess)) {
+                no strict 'refs';
+                $element=&$preprocess($element);
+                use strict 'refs';
+             }
+          }
           if (($type eq 'float') || (($type eq '') && ($unit ne ''))) {
               $element =~ s/\s//g;
           }