--- loncom/homework/default_homework.lcpm	2006/12/15 22:11:43	1.123
+++ loncom/homework/default_homework.lcpm	2008/03/06 14:27:43	1.133
@@ -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 1.123 2006/12/15 22:11:43 www Exp $
+# $Id: default_homework.lcpm,v 1.133 2008/03/06 14:27:43 www Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -157,7 +157,7 @@ sub caparesponse_check {
 
     #&LONCAPA_INTERNAL_DEBUG(" type is $type ");
     if ($type eq 'cs' || $type eq 'ci') {
-	#for string answers make surec all places spaces occur, there is 
+	#for string answers make sure all places spaces occur, there is 
         #really only 1 space, in both the answer and the response
 	$answer=~s/ +/ /g;
 	$response=~s/ +/ /g;
@@ -166,7 +166,7 @@ sub caparesponse_check {
 	$response=~s/[\s,]//g;
     }
     if ($type eq 'float' && $unit=~/\$/) {
-	if ($response!~/^\$/)  { return ('NO_UNIT', undef); }
+	if ($response!~/^\$|\$$/)  { return ('NO_UNIT', undef); }
 	$response=~s/\$//g;
     }
     if ($type eq 'float' && $unit=~/\,/ && (&check_commas($response)<0)) {
@@ -217,6 +217,7 @@ sub caparesponse_check {
 
     my $reterror="";
     my $result;
+    if ((($type eq '9') || ($type eq '8')) && ($response=~/\=/)) { return ('BAD_FORMULA','Please submit just an expression, not an equation.'); }
     if ($type eq '9') {
       $result = &maxima_check(&maxima_cas_formula_fix($response),&maxima_cas_formula_fix($answer),\$reterror);
     } else {
@@ -259,13 +260,10 @@ sub caparesponse_check {
 
 sub caparesponse_check_list {
     my $responses=$LONCAPA::CAPAresponse_args{'response'};
-#    &LONCAPA_INTERNAL_DEBUG(" answer is ".
-#			    &LONCAPA_INTERNAL_Dumper($LONCAPA::CAPAresponse_answer).":\n");
-#    &LONCAPA_INTERNAL_DEBUG(" respons is ".
-#			    &LONCAPA_INTERNAL_Dumper($responses).":\n");
     &LONCAPA_INTERNAL_DEBUG("args ".join(':',%LONCAPA::CAPAresponse_args));
     my $type = $LONCAPA::CAPAresponse_args{'type'};
-    &LONCAPA_INTERNAL_DEBUG("Got type :$type:\n");
+    my $answerunit=$LONCAPA::CAPAresponse_args{'unit'};
+    &LONCAPA_INTERNAL_DEBUG("Got type :$type: answer unit :$answerunit:\n");
     
     my $num_input_lines =
 	scalar(@{$LONCAPA::CAPAresponse_answer->{'answers'}});
@@ -290,8 +288,6 @@ sub caparesponse_check_list {
 	    $responses->[$which]=[$responses->[$which]];
 	}
     }
-#    &LONCAPA_INTERNAL_DEBUG(" parsed response is ".
-#			    &LONCAPA_INTERNAL_Dumper($responses).":\n");
     foreach my $which (0..($num_input_lines-1)) {
 	my $answer_size = 
 	    scalar(@{$LONCAPA::CAPAresponse_answer->{'answers'}[$which]});
@@ -309,19 +305,29 @@ sub caparesponse_check_list {
     my $unit;
     if ($type eq '' || $type eq 'float') {
 	#for numerical problems split off the unit
-	if ( $responses->[0][-1]=~ /(.*[^\s])\s+([^\s]+)/ ) {
+#	if ( $responses->[0][-1]=~ /(.*[^\s])\s+([^\s]+)/ ) {
+        if ( $responses->[0][-1]=~ /^([\d\.\,\s\$]*(?:(?:[xX\*]10[\^\*]*|[eE]*)[\+\-]*\d*)*(?:^|\S)\d+)([\$\s\w\^\*\/\(\)\+\-]*[^\d\.\s\,][\$\s\w\^\*\/\(\)\+\-]*)$/ ) {
 	    $responses->[0][-1]=$1;
-	    $unit=$2;
+	    $unit=&capa_formula_fix($2);
+            &LONCAPA_INTERNAL_DEBUG("Found unit :$unit:");
 	}
     }
     &LONCAPA_INTERNAL_DEBUG("Final final response :$responses->[0][-1]:$unit:");
     $unit=~s/\s//;
-    if ($unit ne '') {
-	foreach my $response (@$responses) {
-	    foreach my $element (@$response) {	    
-		$element .= " $unit";
-	    }
-	}
+    foreach my $response (@$responses) {
+       foreach my $element (@$response) {	
+          $element =~ s/\s//g;
+          my $appendunit=$unit;
+          if ($unit=~/\%/) {
+             $element=$element/100;
+             $appendunit=~s/\%//;
+          }    
+          if (($element==0) && ($unit!~/\w/) && ($answerunit=~/\w/)) {
+             $appendunit=$answerunit;
+          }
+          $element .= " $appendunit";
+          &LONCAPA_INTERNAL_DEBUG("Made response element :$element:");
+       }
     }
     
     foreach my $thisanswer (@{ $LONCAPA::CAPAresponse_answer->{'answers'} }) {
@@ -417,6 +423,15 @@ sub caparesponse_check_list {
     return ($final_award,$final_msg);
 }
 
+sub cas {
+    my ($system,$input)=@_;
+    my $output;
+    if ($system eq 'maxima') {
+       $output=&maxima_eval($input);
+    }
+    return $output;
+}
+
 sub tex {
     if ( $external::target eq "tex" ) {
 	return $_[0];