Happy is a parser generator for Haskell implemented using this library.

Happy is a parser generator for Haskell. Given a grammar specification in BNF, Happy generates Haskell code to parse the grammar. Happy works in a similar way to the yacc tool for C.

This library provides the following functionality:

• Data type definitions for the Grammar AST type, capturing the information in .y-files (Happy.Grammar)

• A parser for happy grammar files (.y) to produce a Grammar (Happy.Frontend.*)

• Implementations of the text book algorithms that compute the LR action and goto tables for the given Grammar (Happy.Tabular.*)

• An LALR code generator to produce table-driven, deterministic parsing code in Haskell (Happy.Backend.LALR.*)

• A (less maintained) GLR code generator to produce table-driven, non-deterministic parsing code in Haskell, where ambiguous parses produce multiple parse trees (Happy.Backend.GLR.*)

Happy

Happy is a parser generator for Haskell 98 (and later).

Happy Parsing!

Documentation

Documentation is hosted on Read the Docs:

• Online (HTML)
• PDF
• Downloadable HTML

For basic information of the sort typically found in a read-me, see the following sections of the docs:

• Introduction
• Obtaining Happy
• Contributing.