#graphvis

Thanks for the input!  I went with nil.  It is more concise and less to type.

I also finished the NFA code.  Currently it only builds the NFA structure; it can't execute anything.  So, I was playing around with it and I thought I'd implement part of a scanner by hand, just for a test.  Here are nodes for scanning string literal, integer, and identifier.

It dumps out its data in GraphVis format, which produces a cute little picture like this.  Next up is to have it generate an NFA from regex.