Lemon is similar to the much more famous programs "YACC" and "BISON". But lemon is not compatible with either yacc or bison. There are several important differences:
The complete source code to the lemon parser generator is contained in two files. The file lemon.c is the parser generator program itself. A separate file lempar.c is the template for the parser subroutine that lemon generates. Documentation on lemon is also available.
Both the source code to lemon itself and the code that lemon generates are in the public domain.
To see an example of how to use lemon, see the source code to the SQLite database engine. Lemon is maintained as part of the SQLite project.