LLLPG Home Page

LLLPG is a recursive-decent LL(k) parser generator for C# that integrates with Visual Studio and generates efficient code, similar to what you would write by hand. Parsers written with LLLPG include Enhanced C# and LES. Help wanted to add additional output languages.

Learn it!

All the documentation is absolutely free!

Tutorial series

• Part 1: Introduction
• Part 2: Simple Examples
• Part 3: Parsing Terminology
• Part 4: Grammar Features
• Part 5: The Loyc Libraries
• Part 6: How to Write a Parser
• Part 7: Error Handling
• Part 8: Managing Ambiguity
• Part 9: Advanced Techniques

Bonus

• Parse JSON in 111 lines of code, print it back in 233

Reference material

• Frequently Asked Questions
• Version history
• Reference: Configuring & invoking LLLPG
• Reference: APIs called by LLLPG
• Reference: The ANTLR-like syntax mode
• Appendix: FullLLk versus "approximate" LL(k)
• Appendix: How LLLPG fits into LeMP & Enhanced C#
• Appendix: Parameters to recognizers

Download & install

LLLPG is distributed with LeMP and Enhanced C#; please see their download & installation instructons. Also, please download the Samples repository so you’ll have some grammars to play with; these demos should compile successfully even before LLLPG is installed.