swgillespie/rp-calc — pull request #1 by swgillespie (2013-12-11 04:01:08+00:00)
Title: Add variable support

By rewriting most of this program using lex and yacc instead of handwritten lexers/parsers, I added a "let" clause that adds support for variables. The format
```
(let )
```
evaluates and sets the result to a variable named . The expression's output is absorbed and not evaluated farther up the syntax tree at this time. An AST of a let expression evaluates to None.

Functions are up next!