Lemon is an LALR parser generator for the C and D programming languages. The original version of Lemon was written by Dr. Richard Hipp and released into the public domain. Lemon is maintained by the SQLite team for use as their SQL parser. Lemon has a number of advantages over traditional parser generators:

• Generated parsers are re-entrant, thread-safe and very performant.
• Grammar includes named non-terminals.
• Support for non-terminal destructors to manage memory.
• Symbolic names for each symbol in a grammar rule reduce programmer error.

• https://www.sqlite.org/src/doc/trunk/doc/lemon.html
• http://code.google.com/p/lemon-parser-generator/
• http://freshmeat.net/articles/view/1270/
• http://en.wikipedia.org/wiki/Lemon_Parser