Developer(s) D. Richard Hipp Operating system License Public domain | Written in C Type Parser generator | |
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".
Lemon, in combination with re2c and a re2c wrapper called Perplex, are used in BRL-CAD as platform-agnostic and easily compilable alternatives to Flex and Bison. This combination is also used with STEPcode.