Lemon Parser Generator

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Lemon Parser Generator
Developer(s) D. Richard Hipp
Written in C
Operating system Cross-platform
Type Parser generator
License Public domain
Website www.hwaci.com/sw/lemon/

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]



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