happy
parser generator for Haskell, similar to yacc for C
TLDR
Generate parser from grammar
$ happy [grammar.y] -o [Parser.hs]
Generate with info file$ happy -i [grammar.y]
Show version$ happy --version
Generate with GHC extensions$ happy -g [grammar.y]
SYNOPSIS
happy [options] file
DESCRIPTION
Happy is a parser generator for Haskell, similar to yacc for C. It takes a grammar specification and produces a Haskell parser module.
The tool generates LALR parsers from BNF-like grammars. It integrates with Alex lexer generator for complete parsing solutions.
PARAMETERS
FILE
Grammar file (.y).-o FILE
Output file name.-i
Generate info file.-g
Use GHC extensions for faster parsers.-a
Generate array-based parser (smaller but slower).-c
Generate GHC-specific parser using GHC primitives.--help
Display help information.
CAVEATS
Haskell specific. Learning curve for grammar syntax. Debugging shift/reduce conflicts.
HISTORY
Happy was created for Haskell as an equivalent to yacc/bison, widely used in Haskell compilers and tools like GHC.
