%define boolean variables

[Joel E. Denny]

Hi Paul,

If you have a moment, would you please consider the following?

For %define variables used as booleans (handled by 
b4_percent_define_flag_if in bison.m4), CVS Bison currently recognizes two 
different possible values to mean false and an infinite number of possible 
values to mean true.  I don't see how this is of any practical use.

Users' grammars will be more consistent and, I believe, more intuitive if 
any %define variable foo is set to true always with:

  %define foo "true"

and is set to false always with:

  %define foo "false"

and if no one ever has to figure out what this means:

  %define foo

or this:

  %define foo "FALSE"

What do you think?

Thanks.