--- loncom/homework/default_homework.lcpm	2004/03/16 19:47:47	1.74
+++ loncom/homework/default_homework.lcpm	2004/03/26 20:10:42	1.77
@@ -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 1.74 2004/03/16 19:47:47 albertel Exp $
+# $Id: default_homework.lcpm,v 1.77 2004/03/26 20:10:42 albertel Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -26,12 +26,7 @@
 # http://www.lon-capa.org/
 #
 #
-# Guy Albertelli
-#
-# 05/25/2001 H. K. Ng
-# 05/31/2001 H. K. Ng
-# 12/21/2001 Matthew
-#
+
 #init some globals
 $hidden::RANDOMINIT=0;
 $pi=atan2(1,1)*4;
@@ -68,7 +63,12 @@ sub caparesponse_check {
     } else {
 	$message .="no ws in :$response:\n";
     }
-
+    if ($type eq 'cs' || $type eq 'ci' || $type eq 'mc') {
+	#for string answers make surec all places spaces occur, there is 
+        #really only 1 space, in both the answer and the response
+	$answer=~s/ +/ /g;
+	$response=~s/ +/ /g;
+    }
     if (length($response) > 500) { return "TOO_LONG: Answer too long"; }
 
     if ($type eq '' ) {
@@ -135,7 +135,11 @@ sub caparesponse_check {
     elsif ($result == '9') { $result='ANS_CNT_NOT_MATCH'; }
     elsif ($result =='10') { $result='SUB_RECORDED'; }
     elsif ($result =='11') { $result='BAD_FORMULA'; }
-    elsif ($result =='12') { $result='WANTED_NUMERIC'; }
+    elsif ($result =='13') { $result='UNIT_INVALID_INSTRUCTOR'; }
+    elsif ($result =='141') { $result='UNIT_INVALID_STUDENT'; }
+    elsif ($result =='142') { $result='UNIT_INVALID_STUDENT'; }
+    elsif ($result =='143') { $result='UNIT_INVALID_STUDENT'; }
+    elsif ($result =='15') { $result='UNIT_IRRECONCIBLE'; }
     else  {$result = "ERROR: Unknown Result:$result:$@:";}
 
     return ("$result:\nRetError $reterror:\nError $error:\nAnswer $answer:\nResponse $response:\n type-$type|$tol|$tol_type|$sig:$sig_lbound:$sig_ubound|$unit|\n$message",$reterror);
@@ -485,11 +489,51 @@ sub format {
     return $result;
 }
 
+sub chemparse {
+    my ($reaction) = @_;
+    my @tokens = split(/(\s\+|\->|<=>)/,$reaction);
+    my $formula = '';
+    foreach my $token (@tokens) {
+	if ($token eq '->' ) {
+	    $formula .= '<m>\ensuremath{\rightarrow}</m> ';
+	    next;
+	}
+	if ($token eq '<=>') {
+	    if ($external::target eq 'web' &&
+		&EXT('request.browser.unicode')) {
+		$formula .= '&#8652; ';
+	    } else {
+		$formula .= &web('<=> ','<m>\ensuremath{\rightleftharpoons}</m> ',
+				 '&lt;=$gt; ');
+	    }
+	    next;
+	}
+	$token =~ /^\s*(\d*)(.*)/;
+	$formula .= $1 if ($1 > 1);  # stoichiometric coefficient
+	
+	my $molecule = $2;
+	# subscripts
+	$molecule =~ s|(?<=[a-zA-Z\[\s])(\d+)|<sub>$1</sub>|g;
+	# superscripts
+	$molecule =~ s|\^(\d*[+\-]*)|<sup>$1</sup>|g;
+	# strip whitespace
+	$molecule =~ s/\s*//g;
+	# forced space
+	$molecule =~ s/_/ /g;
+	$formula .= $molecule.'&nbsp;';
+    }
+    # get rid of trailing space
+    $formula =~ s/(\Q${nbsp}\E| )$//;
+    
+    return &xmlparse($formula);
+}
+
 sub prettyprint {
     my ($value,$fmt,$target)=@_;
     my $result;
     my $dollarmode;
     if (!$target) { $target = $external::target; }
+    if ($fmt =~ /chem/i) { return(&chemparse($value)); }
     if ($fmt =~ /^\$(.*)/) { $fmt=$1; $dollarmode=1; } 
     if ($fmt) { $value=sprintf('%.'.$fmt,$value); }
     if ($value =~ /([0-9\.\-\+]+)E([0-9\-\+]+)/i ) {