ref: cf357b748945f161ed4a4c7ebac9e1353f3307a3
parent: 4fac3196061c75f159d37bd8e7e51dc64f0dd5df
author: Ori Bernstein <ori@eigenstate.org>
date: Sun Jul 5 07:36:46 EDT 2015
Add proper support for a 'gap' variable.
'_' is now a reserved token.