The Lemon program is an LALR(1) parser generator. It takes a context free grammar and converts it into a subroutine that will parse a file using that grammar.
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:
- Lemon using a different grammar syntax which is less prone to programming errors.
- The parser generated by Lemon is both re-entrant and thread-safe.
- Lemon includes the concept of a non-terminal destructor, which makes it much easier to write a parser that does not leak memory.
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.
Lemon is intended to be used as a self contained part of your project. We set this repository up to make it possible to use Lemon through a git submodule. This helps you, to easily update your Lemon dependency. We keep track of new releases.
To set up your Lemon through a git submodule run the following line in your projects root folder:
git submodule add https://github.com/compiler-dept/lemon.git lemon
As Lemon needs to be compiled, you can easily add lemon to your Makefile:
lemon:
@make -C lemon