Attached is a modified version of p9p yacc that
supports the Go grammar.  I'll be sending a
version of Plan 9 yacc later today.

The following is a description of the changes.

  1. The %error-verbose directive is ignored.

  2. A description of the final grammar is
     printed before the state descriptions
	 in y.output.

  3. The 'x' format for character literals is
     now used instead of prefixing with a space.

  4. The YYEMPTY define is now used to clear
     the lookahead token (instead of an explicit
	 negative one).

  5. Make yychar and yystate globals so they
     can be inspected by external code.

  5. Support C++ style // comments in actions.

  6. Add a usage message.

  7. Fix a few uses of sprint and strcpy.


I've also sent out a changeset to the Go
development list which adds support for
using Plan 9 yacc to generate the special
errors.

One tiny nit is that Plan 9 uses the name
yytoknames for debugging where Bison uses
yytname.  I've just used sed for this.

Any questions?
  Anthony