--- loncom/homework/inputtags.pm	2004/10/19 15:24:32	1.152
+++ loncom/homework/inputtags.pm	2004/11/06 01:11:38	1.154
@@ -1,7 +1,7 @@
 # The LearningOnline Network with CAPA
 # input  definitons
 #
-# $Id: inputtags.pm,v 1.152 2004/10/19 15:24:32 albertel Exp $
+# $Id: inputtags.pm,v 1.154 2004/11/06 01:11:38 albertel Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -317,7 +317,7 @@ sub finalizeawards {
 			       'BAD_FORMULA', 'SIG_FAIL', 'INCORRECT', 
 			       'MISORDERED_RANK', 'INVALID_FILETYPE',
 			       'DRAFT', 'SUBMITTED', 'ASSIGNED_SCORE',
-			       'APPROX_ANS', 'EXACT_ANS') {
+			       'APPROX_ANS', 'EXACT_ANS','COMMA_FAIL') {
 	($result,$msg)=&checkstatus($possibleaward,$awardref,$msgref);
 	if (defined($result)) { return ($result,$msg); }
     }
@@ -457,6 +457,10 @@ sub decideoutput {
 	if ($target ne 'tex') {$message.=&Apache::loncommon::help_open_topic('Physical_Units')};
 	$bgcolor=$possiblecolors{'not_charged_try'};
 	$button=1;
+    } elsif ($award eq 'COMMA_FAIL') {
+	$message = &mt("Proper comma separation is required").'.';
+	$bgcolor=$possiblecolors{'not_charged_try'};
+	$button=1;
     } elsif ($award eq 'BAD_FORMULA') {
 	$message = &mt("Unable to understand formula");
 	$bgcolor=$possiblecolors{'not_charged_try'};
@@ -524,10 +528,15 @@ sub hidealldata {
 
 sub setgradedata {
     my ($award,$msg,$id,$previously_used) = @_;
-    # if the student already has it correct, don't modify the status
-    if ($Apache::lonhomework::scantronmode && defined($ENV{'form.CODE'})) {
+    if ($Apache::lonhomework::scantronmode && 
+	&Apache::lonnet::validCODE($ENV{'form.CODE'})) {
 	$Apache::lonhomework::results{"resource.CODE"}=$ENV{'form.CODE'};
+    } elsif ($Apache::lonhomework::scantronmode && 
+	     $ENV{'form.CODE'} eq '' &&
+	     $Apache::lonhomework::history{"resource.CODE"} ne '') {
+	$Apache::lonhomework::results{"resource.CODE"}='';
     }
+
     if (!$Apache::lonhomework::scantronmode &&
 	$Apache::inputtags::status['-1'] ne 'CAN_ANSWER' &&
 	$Apache::inputtags::status['-1'] ne 'CANNOT_ANSWER') {
@@ -536,7 +545,10 @@ sub setgradedata {
     } elsif ( $Apache::lonhomework::history{"resource.$id.solved"} !~
 	      /^correct/ || $Apache::lonhomework::scantronmode ||
 	      lc($Apache::lonhomework::problemstatus) eq 'no') {
-	#handle assignment of tries and solved status
+        # the student doesn't already have it correct,
+	# or we are in a mode (scantron orno problem status) where a correct 
+        # can become incorrect
+	# handle assignment of tries and solved status
 	my $solvemsg;
 	if ($Apache::lonhomework::scantronmode) {
 	    $solvemsg='correct_by_scantron';