tree e4ab1b95e04e1b98cd6769d3798e1cf05f0a4075
parent 1c3d964395ce8f04f3b03b30aaed0b096c08c3c6
author Ian Cottrell <iancottrell@google.com> 1543602227 -0500
committer Ian Cottrell <iancottrell@google.com> 1543607866 +0000

go/expect: rewrite the expectation parser

The expectation langauge is LL(1) but the scanner does not support true
lookahead
This change adds a true LL(1) token stream and rewrites the parser in terms of
it.
Also clean up the error handling and use the behaviour to fix all the broken
edge cases, and then change the tests to cover the now correct behaviour.

Change-Id: If3d602cda490ed2f4732efce400eb8eabce8a8ec
Reviewed-on: https://go-review.googlesource.com/c/151998
Run-TryBot: Ian Cottrell <iancottrell@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rebecca Stambler <rstambler@golang.org>