Lemon Parser Generator

Lemon is a parser generator, maintained as part of the SQLite project, that generates an LALR parser in the C programming language from an input context-free grammar. The generator is quite simple, implemented in a single C source file with another file used as a template for output. Lexical analysis is performed externally.

Lemon is similar to bison and yacc; however it is not compatible with these programs. The grammar input format is different, so as to help prevent common coding errors. Other distinctive features include a reentrant, thread-safe output parser, and the concept of "non-terminal destructors" that try to make it easier to avoid leaking memory.

SQLite uses Lemon with a hand-coded tokenizer to parse SQL strings.

In 2008 a Lemon-generated parser was suggested to replace the bison-generated parser used for the PHP programming language; as of 2010 this project was listed as "in the works".^[1]

Lemon, in combination with re2c and a re2c wrapper called Perplex, are used^[2][3][4] in BRL-CAD as platform-agnostic and easily compilable alternatives to Flex and Bison. This combination is also used with STEPcode.^[5]

Notes

References

• "The LEMON Parser Generator". Retrieved 2008-12-24. 
• "Architecture of SQLite". 2008-11-01. Retrieved 2008-12-24. 

External links

• The Lemon Parser Generator
• Calculator with Lemon and Lex in C++ Example
• Understanding Lemon generated Parser
• Lemon, bundled with Re2c and Perplex