--- loncom/homework/response.pm	2006/12/15 21:10:13	1.155
+++ loncom/homework/response.pm	2007/02/24 01:44:14	1.159
@@ -1,7 +1,7 @@
 # The LearningOnline Network with CAPA
 # various response type definitons response definition
 #
-# $Id: response.pm,v 1.155 2006/12/15 21:10:13 www Exp $
+# $Id: response.pm,v 1.159 2007/02/24 01:44:14 albertel Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -368,7 +368,8 @@ sub start_customresponse {
     my $id = &Apache::response::start_response($parstack,$safeeval);
     push(@Apache::lonxml::namespace,'customresponse');
     my $result;
-    undef($Apache::response::custom_answer);
+    @Apache::response::custom_answer=();
+    @Apache::response::custom_answer_type=();
     &Apache::lonxml::register('Apache::response',('answer'));
     if ($target eq 'web') {
   	if (  &Apache::response::show_answer() ) {
@@ -408,7 +409,7 @@ sub end_customresponse {
 	    &Apache::response::submitted('scantron')) {
 	    &Apache::response::scored_response($part,$id);
 	} elsif ( $response =~ /[^\s]/ && 
-		  $Apache::response::custom_answer_type eq 'loncapa/perl') {
+		  $Apache::response::custom_answer_type[-1] eq 'loncapa/perl') {
 	    if (!$Apache::lonxml::default_homework_loaded) {
 		&Apache::lonxml::default_homework_load($safeeval);
 	    }
@@ -420,7 +421,7 @@ sub end_customresponse {
 	    ${$safeeval->varglob('LONCAPA::customresponse_submission')}=
 		$response;
 	    
-	    my $award = &Apache::run::run('{ my $submission=$LONCAPA::customresponse_submission;'.$Apache::response::custom_answer.'}',$safeeval);
+	    my $award = &Apache::run::run('{ my $submission=$LONCAPA::customresponse_submission;'.$Apache::response::custom_answer[-1].'}',$safeeval);
 	    if (!&Apache::inputtags::valid_award($award)) {
 		$error = $award;
 		$award = 'ERROR';
@@ -448,6 +449,8 @@ sub end_customresponse {
 	&Apache::lonxml::increment_counter(&Apache::response::repetition());
     }
     pop(@Apache::lonxml::namespace);
+    pop(@Apache::response::custom_answer);
+    pop(@Apache::response::custom_answer_type);
     &Apache::lonxml::deregister('Apache::response',('answer'));
     &Apache::response::end_response();
     return $result;
@@ -459,7 +462,8 @@ sub start_mathresponse {
     my $id = &Apache::response::start_response($parstack,$safeeval);
     push(@Apache::lonxml::namespace,'mathresponse');
     my $result;
-    undef($Apache::response::custom_answer);
+    @Apache::response::custom_answer=();
+    @Apache::response::custom_answer_type=();
     &Apache::lonxml::register('Apache::response',('answer'));
     if ($target eq 'web') {
   	if (  &Apache::response::show_answer() ) {
@@ -514,7 +518,7 @@ sub end_mathresponse {
 	    my $cas = &Apache::lonxml::get_param('cas',$parstack,$safeeval);
             if ($cas eq 'maxima') {
                 my $args = [&Apache::lonxml::get_param_var('args',$parstack,$safeeval)];
-                $award=&Apache::lonmaxima::maxima_run($Apache::response::custom_answer,$response,$args);
+                $award=&Apache::lonmaxima::maxima_run($Apache::response::custom_answer[-1],$response,$args);
             }
 	    if (!&Apache::inputtags::valid_award($award)) {
 		$error = $award;
@@ -530,24 +534,48 @@ sub end_mathresponse {
 	}
     }
     pop(@Apache::lonxml::namespace);
+    pop(@Apache::response::custom_answer);
+    pop(@Apache::response::custom_answer_type);
     &Apache::lonxml::deregister('Apache::response',('answer'));
     &Apache::response::end_response();
     return $result;
 }
 
+sub implicit_multiplication {
+    my ($expression)=@_;
+# Escape scientific notation, so 3e8 does not become 3*e*8
+# 3e8 -> 3&8; 3e-8 -> 3&-8; 3E+8 -> e&+8
+    $expression=~s/(\d+)e([\+\-]*\d+)/$1\&\($2\)/gsi;
+# 3x10^8 -> 3&8; 3*10^-8 -> 3&-8
+    $expression=~s/(\d+)(?:x|\*)10(?:\^|\*\*)([\+\-]*\d+)/$1\&\($2\)/gsi;
+# Fill in multiplication signs
+# a b -> a*b;3 b -> 3*b;3 4 -> 3*4
+    $expression=~s/(\w)\s+(\w)/$1\*$2/gs;
+# )( -> )*(; ) ( -> )*(
+    $expression=~s/\)\s*\(/\)\*\(/gs;
+# 3a -> 3*a; 3( -> 3*(; 3 ( -> 3*(; 3A -> 3*A
+    $expression=~s/(\d)\s*([a-zA-Z\(])/$1\*$2/gs;
+# a ( -> a*(
+    $expression=~s/(\w)\s+\(/$1\*\(/gs;
+# )a -> )*a; )3 -> )*3; ) 3 -> )*3
+    $expression=~s/\)\s*(\w)/\)\*$1/gs;
+# 3&8 -> 3e8; 3&-4 -> 3e-4
+    $expression=~s/(\d+)\&\(([\+\-]*\d+)\)/$1e$2/gs;
+    return $expression;
+}
 
 sub start_answer {
     my ($target,$token,$tagstack,$parstack,$parser,$safeeval)=@_;
     my $result;
-    $Apache::response::custom_answer=
-	&Apache::lonxml::get_all_text_unbalanced("/answer",$parser);
-    $Apache::response::custom_answer_type=
-	lc(&Apache::lonxml::get_param('type',$parstack,$safeeval));
-    $Apache::response::custom_answer_type =~ s/\s+//g;
+    push(@Apache::response::custom_answer,
+	&Apache::lonxml::get_all_text_unbalanced("/answer",$parser));
+    push(@Apache::response::custom_answer_type,
+	lc(&Apache::lonxml::get_param('type',$parstack,$safeeval)));
+    $Apache::response::custom_answer_type[-1] =~ s/\s+//g;
     if ($target eq "edit" ) {
 	$result=&Apache::edit::tag_start($target,$token,'Answer algorithm');
 	$result.=&Apache::edit::editfield($token->[1],
-					  $Apache::response::custom_answer,
+					  $Apache::response::custom_answer[-1],
 					  '',80,4);
     } elsif ( $target eq "modified" ) {
 	$result=$token->[4].&Apache::edit::modifiedfield('/answer',$parser);
@@ -998,7 +1026,13 @@ sub submitted {
     if ($who eq 'scantron') { return 0; }
     # if the Submit Answer button for this particular part was pressed
     my $partid=$Apache::inputtags::part;
-    if (defined($env{'form.submit_'.$partid})) { return 1; }
+    if ($env{'form.submitted'} eq "part_$partid") {
+	return 1;
+    }
+    if ($env{'form.submitted'} eq "yes"
+	&& defined($env{'form.submit_'.$partid})) {
+	return 1;
+    }
     # Submit All button on a .page was pressed
     if (defined($env{'form.all_submit'})) { return 1; }
     # otherwise no submission occured