Leex is an erlang version of Lex, a Lexical Analyzer Generator written by Robert Virding. Robert (and several others in #erlang on freenode) were incredibly helpful and considerate in helping me understand these tools. Leex is a tokenizer. It breaks the pieces of your file or text into tokens. You can then use a tool like yecc to take these tokens and generate useful parsers. First, you’ll need the source. Leex source is available here.