Lex and YACC are two programs which have been used for over a decade to parse and help compile programming languages and configuration files. Even though there are books available that tell you how to use them, little or no online HOWTO-style documentation is available. This document gets you up to speed quickly. It is unique in that it is possibly the only online resource that treats this subject from a non-CS perspective. No prior knowledge of tokenizers or state machines is needed. It comes with working examples and compilation instructions.
Release Notes: This release includes a section on writing a C++ parser, fixes for left/right recursion problems, a section on recursion, a section on how to debug your lexer/parser, removal of yywrap()'s FIXME, improved and simplified examples, explanations of shift/reduce and reduce/reduce conflicts, some typo corrections, and the HOWTO is nearing completeness.