cmd/internal/gc, cmd/yacc: restore remaining custom error messages

This CL extends cmd/yacc to expose a yyErrorVerbose variable that
changes the error messages from just "syntax error" to "syntax error:
unexpected ${tokname}".

It also moves the yyToknames table generation to after rules have been
processed so that entries can be generated for tokens that aren't
mentioned in the preamble (e.g., '.' in the case of go.y).

Lastly, it restores gc's old code for applying yytfix to yyToknames,
except that substituting "LLITERAL" with litbuf happens in Yyerror.

Fixes #9968.

Change-Id: Icec188d11fdabc1dae31b8a471c35b5c7f6deec7
Reviewed-on: https://go-review.googlesource.com/8432
Reviewed-by: Russ Cox <rsc@golang.org>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
8 files changed
tree: e98cd73442bb9cb8f3375774133120f2771a2c72
  1. api/
  2. doc/
  3. lib/
  4. misc/
  5. src/
  6. test/
  7. .gitattributes
  8. .gitignore
  9. AUTHORS
  10. CONTRIBUTING.md
  11. CONTRIBUTORS
  12. favicon.ico
  13. LICENSE
  14. PATENTS
  15. README.md
  16. robots.txt
README.md

The Go Programming Language

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Binary Distribution Notes

If you have just untarred a binary Go distribution, you need to set the environment variable $GOROOT to the full path of the go directory (the one containing this file). You can omit the variable if you unpack it into /usr/local/go, or if you rebuild from sources by running all.bash (see doc/install-source.html). You should also add the Go binary directory $GOROOT/bin to your shell's path.

For example, if you extracted the tar file into $HOME/go, you might put the following in your .profile:

export GOROOT=$HOME/go
export PATH=$PATH:$GOROOT/bin

See https://golang.org/doc/install or doc/install.html for more details.