--- loncom/homework/response.pm	2007/06/26 01:40:47	1.173
+++ loncom/homework/response.pm	2007/08/10 18:16:28	1.174
@@ -1,7 +1,7 @@
 # The LearningOnline Network with CAPA
 # various response type definitons response definition
 #
-# $Id: response.pm,v 1.173 2007/06/26 01:40:47 albertel Exp $
+# $Id: response.pm,v 1.174 2007/08/10 18:16:28 riegler Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -569,15 +569,16 @@ sub implicit_multiplication {
     $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\*$2/gs;
+# The while-pos-construction is necessary for a b c -> a*b*c*d instead of a*b c*d
+    while($expression=~s/([A-Za-z0-9])\s+([A-Za-z0-9])/$1\*$2/gs){pos($expression)--}
 # )( -> )*(; ) ( -> )*(
     $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;
+    $expression=~s/([A-Za-z0-9])\s+\(/$1\*\(/gs;
 # )a -> )*a; )3 -> )*3; ) 3 -> )*3
-    $expression=~s/\)\s*(\w)/\)\*$1/gs;
+    $expression=~s/\)\s*([A-Za-z0-9])/\)\*$1/gs;
 # 3&8 -> 3e8; 3&-4 -> 3e-4
     $expression=~s/(\d+)\&\(([\+\-]*\d+)\)/$1e$2/gs;
     return $expression;