This directory contains a yacc grammar that was started from
the yacc grammar in the source of the go compiler itself before
it was removed at:

commit b5fe07710f4a31bfc100fbc2e344be11e4b4d3fc
Author: Robert Griesemer <gri@golang.org>
Date:   Mon Nov 23 14:11:15 2015 -0800

    cmd/compile: remove yacc-based parser

    - moved yySymType and token constants (L...) to lex.go
    - removed oldparser flag and related code
    - removed go generate that generated y.go

    Fixes #13240.

    Change-Id: I2576ec61ee1efe482f2a5132175725c9c02ef977
    Reviewed-on: https://go-review.googlesource.com/17176
    Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>


So the grammar and lexer files are accessible in
git checkout b5fe07710f4a31bfc100fbc2e344be11e4b4d3fc^
in src/cmd/compile/internal/gc/go.y
