[WWcvs] pg: Fix problem with negating mixed numbers

[dpvc v. a. <we...@ma...>]

Log Message:
-----------
Fix problem with negating mixed numbers

Modified Files:
--------------
    pg/macros:
        contextFraction.pl

Revision Data
-------------
Index: contextFraction.pl
===================================================================
RCS file: /webwork/cvs/system/pg/macros/contextFraction.pl,v
retrieving revision 1.13
retrieving revision 1.14
diff -Lmacros/contextFraction.pl -Lmacros/contextFraction.pl -u -r1.13 -r1.14
--- macros/contextFraction.pl
+++ macros/contextFraction.pl
@@ -441,7 +441,7 @@
   if ($isFraction) {
     $self->Error("Mixed numbers are not allowed; you must use a pure fraction")
       if ($self->context->flag("requirePureFractions"));
-    $self->{bop} = "  ";
+    $self->{isFraction} = 1; $self->{bop} = "  ";
     $self->{def} = $self->context->{operators}{$self->{bop}};
     if ($self->{lop}->class eq 'MINUS') {
       #
@@ -463,6 +463,15 @@
 }
 
 #
+#  Indicate if the value is a fraction or not
+#
+sub class {
+  my $self = shift;
+  return "FRACTION" if $self->{isFraction};
+  return $self->SUPER::class;
+}
+
+#
 #  Reduce the fraction
 #
 sub reduce {