A Pratt parsing library, easy to include and use in a programming language project. It allows for simple run-time grammar extensions.
Pratt parsing is a simple top-down operator precedence parsing algorithm, invented by Vaughan Pratt. It is very easy to add syntax extensions at runtime, due to the algorithm's use of a lookup dictionary; to extend the accepted syntax of a language,
add an entry to the parselet dictionary.
This is a small project that I just coded up for use in a project of mine. I have not checked it for bugs or correctness, but I'm pretty sure it works!