--- loncom/homework/default_homework.lcpm	2008/11/26 18:11:52	1.142
+++ loncom/homework/default_homework.lcpm	2010/10/14 19:54:56	1.149
@@ -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 1.142 2008/11/26 18:11:52 raeburn Exp $
+# $Id: default_homework.lcpm,v 1.149 2010/10/14 19:54:56 raeburn Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -220,7 +220,7 @@ sub caparesponse_check {
     if (($type eq '9') || ($type eq '8')) {
         if ($response=~/\=/) {
             return ('BAD_FORMULA','Please submit just an expression, not an equation.');
-        } elsif ($response =~ /\,/) {
+        } elsif ($response =~ /\,/ and $response !~ /^\s*\{.*\}\s*$/) {
             return ('BAD_FORMULA');
         }
     }
@@ -320,20 +320,33 @@ sub caparesponse_check_list {
     }
     &LONCAPA_INTERNAL_DEBUG("Final final response :$responses->[0][-1]:$unit:");
     $unit=~s/\s//;
+    my $error;
     foreach my $response (@$responses) {
        foreach my $element (@$response) {	
           if (($type eq 'float') || (($type eq '') && ($unit ne ''))) {
               $element =~ s/\s//g;
           }
           my $appendunit=$unit;
-          if (($unit=~/\%/) && ($answerunit ne '%'))  {
-             $element=$element/100;
-             $appendunit=~s/\%//;
-          }    
+# Deal with percentages
+# unit is unit entered by student, answerunit is unit by author
+# Deprecated: divide answer by 100 if student entered percent,
+# but author did not. Too much confusion
+#          if (($unit=~/\%/) && ($answerunit ne '%'))  {
+#             $element=$element/100;
+#             $appendunit=~s/\%//;
+#          }    
+# Author entered percent, student did not
+          if (($unit!~/\%/) && ($answerunit=~/\%/)) {
+             $element=$element*100;
+             $appendunit='%'.$appendunit;
+          }
+# Zero does not need a dimension
           if (($element==0) && ($unit!~/\w/) && ($answerunit=~/\w/)) {
              $appendunit=$answerunit;
           }
-          $element .= " $appendunit";
+          if ($appendunit ne '') {
+              $element .= " $appendunit";
+          }  
           &LONCAPA_INTERNAL_DEBUG("Made response element :$element:");
        }
     }
@@ -356,6 +369,10 @@ sub caparesponse_check_list {
 	    for (my $j=0; $j<scalar(@$response); $j++) { 
 		my ($award,$msg) = &caparesponse_check($answer->[$j],
 						       $response->[$j]);
+                if ($type eq 'cs' || $type eq 'ci') {
+                    $error = &verify_stringresponse($type,$award,$response->[$j],
+                                                    $answer->[$j]);
+                }
 		push(@awards,$award);
 		push(@msgs,  $msg);
 	    }
@@ -382,6 +399,10 @@ sub caparesponse_check_list {
 		    for (my $j=0; $j<scalar(@$response); $j++) {
 			my ($award,$msg) = &caparesponse_check($answer->[$j],
 							       $response->[$j]);
+                        if ($type eq 'cs' || $type eq 'ci') {
+                            $error = &verify_stringresponse($type,$award,$response->[$j],
+                                                            $answer->[$j]);
+                        }
 			push(@awards,$award);
 			push(@msgs,  $msg);
 		    }
@@ -428,20 +449,75 @@ sub caparesponse_check_list {
     &LONCAPA_INTERNAL_DEBUG(" all final_awards ".join(':',@final_awards));
     my ($final_award,$final_msg) = 
 	&LONCAPA_INTERNAL_FINALIZEAWARDS(\@final_awards,\@final_msg,undef,1);
-    return ($final_award,$final_msg);
+    return ($final_award,$final_msg,$error);
+}
+
+sub verify_stringresponse {
+    my ($type,$award,$resp,$ans) = @_;
+    return if ($award eq 'EXACT_ANS');
+    my $error;
+    if ($resp =~ /^\s|\s$/) {
+        $resp =~ s{^\s+|\s+$}{}g;
+    }
+    if ($ans =~ /^\s|\s$/) {
+        $ans =~ s{^\s+|\s+$}{}g;
+    }
+    if ($type eq 'ci') {
+        $resp = lc($resp);
+        $ans = lc($ans);
+    }
+    if ($resp eq $ans) {
+        if ($award eq 'INCORRECT') {
+            $error = 'MISGRADED';
+        }
+    }
+    return $error;
 }
 
 sub cas {
     my ($system,$input,$library)=@_;
     my $output;
+    my $dump;
     if ($system eq 'maxima') {
        $output=&maxima_eval($input,$library);
+    } elsif ($system eq 'R') {
+       ($output,$dump)=&r_eval($input,$library,0);
     } else {
        $output='Error: unrecognized CAS';
     }
     return $output;
 }
 
+sub cas_hashref {
+    my ($system,$input,$library)=@_;
+    if ($system eq 'maxima') {
+       return 'Error: unsupported CAS';
+    } elsif ($system eq 'R') {
+       return &r_eval($input,$library,1);
+    } else {
+       return 'Error: unrecognized CAS';
+    }
+}
+
+#
+# cas_hashref_entry takes a list of indices and gets the entry in a hash generated by Rreturn.
+# Call: cas_hashref_entry(Rvalue, index1, index2, ...) where Rvalue is a hash returned by Rreturn.
+# Rentry will return the first scalar value it encounters (ignoring excess indices).
+# If an invalid key is given, it returns undef.
+#
+sub cas_hashref_entry {
+    return &Rentry(@_);
+}
+
+#
+# cas_hashref_array takes a list of indices and gets a column array from a hash generated by Rreturn.
+# Call: cas_hashref_array(Rvalue, index1, index2, ...) where Rvalue is a hash returned by Rreturn.
+# If an invalid key is given, it returns undef.
+#
+sub cas_hashref_array {
+    return &Rarray(@_);
+}
+
 sub tex {
     if ( $external::target eq "tex" ) {
 	return $_[0];