language-javascript: Parser for JavaScript

[ bsd3, language, library ] [ Propose Tags ]
Versions 0.0.1, 0.0.2, 0.0.3, 0.1.0, 0.2.0, 0.2.1, 0.2.2, 0.3.0, 0.4.0, 0.4.1, 0.4.2, 0.4.3, 0.4.4, 0.4.5, 0.4.6, 0.4.7, 0.4.8, 0.4.9, 0.4.10, 0.5.0, 0.5.1, 0.5.2, 0.5.3, 0.5.4, 0.5.5, 0.5.6, 0.5.7, 0.5.8, 0.5.9, 0.5.11, 0.5.12, 0.5.13,,,,,,,,,,,,,,,,,,,,,,,,,
Dependencies array (>=0.3), base (==4.*), blaze‑builder (>=0.2), bytestring (>=0.9.1), containers (>=0.2), mtl (>=1.1), semigroups (>=0.16.1), text (>=1.2), utf8‑string (>=0.3.7 && <2) [details]
License BSD-3-Clause
Copyright (c) 2010-2015 Alan Zimmerman, 2015 Erik de Castro Lopo
Author Alan Zimmerman
Maintainer Erik de Castro Lopo <>
Category Language
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Source repo head: git clone
Uploaded by ErikDeCastroLopo at Thu Mar 15 21:51:09 UTC 2018
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Downloads 45732 total (247 in the last 30 days)
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Status Docs available [build log]
Last success reported on 2018-03-15 [all 1 reports]
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Parses Javascript into an Abstract Syntax Tree (AST). Initially intended as frontend to hjsmin.

Note: Version 0.5.0 breaks compatibility with prior versions, the AST has been reworked to allow round trip processing of JavaScript.

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Readme for language-javascript-

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Parser for JavaScript

Build Status

Based (loosely) on language-python

Two Versions

There are currently two versions:

  • 0.5 series : Is a continuation of the 0.5.X.Y series, from the [master] ( branch of this github repository.

  • 0.6 series : This has a vastly different and improved AST which makes if far more difficult to build an non-sensical Javascript AST. This code is in the new-ast branch of this github repository.

How to build


cabal clean && cabal configure && cabal build


cabal clean && cabal configure -fbuildtests && cabal build

Running the tests


To debug the grammar

happy -iparse.txt -g -a  -d src/Language/JavaScript/Parser/Grammar5.y

This generates src/Language/JavaScript/Parser/Grammar5.hs, delete this when done with the debug version

UTF8/Unicode version

Alex 3.0 now supports unicode natively, and has been included as a dependency in the cabal file.

Note: The generation of the lexical analyser has been separated out, to remove the install-time dependency on Alex. If any changes need to be made to the lexer, the Lexer.x source lies in src-dev, and the script will invoke Alex with the appropriate directories.