[WWcvs] pg: Make sure clear doesn't remove the special 'start' paren that is required by the Parser class.

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

Log Message:
-----------
Make sure clear doesn't remove the special 'start' paren that is
required by the Parser class.

Modified Files:
--------------
    pg/lib/Parser/Context:
        Parens.pm

Revision Data
-------------
Index: Parens.pm
===================================================================
RCS file: /webwork/cvs/system/pg/lib/Parser/Context/Parens.pm,v
retrieving revision 1.7
retrieving revision 1.8
diff -Llib/Parser/Context/Parens.pm -Llib/Parser/Context/Parens.pm -u -r1.7 -r1.8
--- lib/Parser/Context/Parens.pm
+++ lib/Parser/Context/Parens.pm
@@ -30,6 +30,15 @@
   delete $self->{tokens}{$data->{close}} unless $data->{hidden} || $data->{close} eq $token;
 }
 
+#
+#  Always retain 'start' since it si crucial to the parser
+#
+sub clear {
+  my $self = shift;
+  $self->SUPER::clear();
+  $self->redefine('start');
+}
+
 #########################################################################
 
 1;