The hexpat package

[Tags:bsd3, library]

This package provides a general purpose Haskell XML library using Expat to do its parsing ( - a fast stream-oriented XML parser written in C). It is extensible to any string type, with String, ByteString and Text provided out of the box.

Basic usage: Parsing a tree (Tree), formatting a tree (Format). Other features: Helpers for processing XML trees (Proc), trees annotated with XML source location (Annotated), XML cursors (Cursor), SAX-style parse (SAX), and access to the low-level interface in case speed is paramount (Internal.IO).

The design goals are speed, speed, speed, interface simplicity and modularity.

For introduction and examples, see the Text.XML.Expat.Tree module. For benchmarks,

If you want to do interactive I/O, an obvious option is to use lazy parsing with one of the lazy I/O functions such as hGetContents. However, this can be problematic in some applications because it doesn't handle I/O errors properly and can give no guarantee of timely resource cleanup. In these cases, chunked I/O is a better approach: Take a look at the hexpat-iteratee package.

IO is filed under Internal because it's low-level and most users won't want it. The other Internal modules are re-exported by Annotated and Tree, so you won't need to import them directly.

Credits to Iavor Diatchki and the xml (XML.Light) package for Proc and Cursor.

INSTALLATION: Unix install requires an OS package called something like libexpat-dev. On MacOSX, expat comes with Apple's optional X11 package, or you can install it from source. To install on Windows, first install the Windows binary that's available from, then type (assuming you're using v2.0.1):

cabal install hexpat --extra-lib-dirs=C:\Program Files\Expat 2.0.1\Bin --extra-include-dirs=C:\Program Files\Expat 2.0.1\Source\Lib

Ensure libexpat.dll can be found in your system PATH (or copy it into your executable's directory).

ChangeLog: 0.15 changes intended to fix a (rare) "error: a C finalizer called back into Haskell." that seemed only to happen only on ghc6.12.X; 0.15.1 Fix broken Annotated parse; 0.16 switch from mtl to transformers; 0.17 fix mapNodeContainer & rename some things.; 0.18 rename defaultEncoding to overrideEncoding.


Versions 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 0.10, 0.11, 0.12, 0.13, 0.14, 0.15, 0.15.1, 0.16, 0.17, 0.18, 0.18.1, 0.18.2, 0.18.3, 0.19, 0.19.1, 0.19.2, 0.19.3, 0.19.4, 0.19.5, 0.19.6, 0.19.7, 0.19.8, 0.19.9, 0.19.10, 0.20.1, 0.20.2, 0.20.3, 0.20.4, 0.20.5, 0.20.6, 0.20.7, 0.20.8, 0.20.9, 0.20.10
Dependencies base (>=3 && <5), bytestring, containers, extensible-exceptions (==0.1.*), List (>=0.4), parallel (<, text (>=0.5), transformers, utf8-string (>=0.3.3) [details]
License BSD3
Copyright (c) 2009 Doug Beardsley <>, (c) 2009-2010 Stephen Blackheath <>, (c) 2009 Gregory Collins, (c) 2008 Evan Martin <>, (c) 2009 Matthew Pocock <>, (c) 2007-2009 Galois Inc.
Author Stephen Blackheath [blackh] (the primary author), Doug Beardsley, Gregory Collins, Evan Martin (who started the project), Matthew Pocock [drdozer]
Stability beta
Category XML
Home page
Source repository head: darcs get
Uploaded Wed Jul 21 23:10:05 UTC 2010 by StephenBlackheath
Distributions FreeBSD:0.20.9, LTSHaskell:0.20.10, NixOS:0.20.9, Stackage:0.20.10
Downloads 29221 total (274 in the last 30 days)
0 []
Status Docs not available [build log]
All reported builds failed as of 2016-12-29 [all 7 reports]


  • Text
    • XML
      • Expat
        • Text.XML.Expat.Annotated
        • Text.XML.Expat.Cursor
        • Text.XML.Expat.Format
        • Text.XML.Expat.IO
        • Internal
          • Text.XML.Expat.Internal.IO
          • Text.XML.Expat.Internal.Namespaced
          • Text.XML.Expat.Internal.NodeClass
          • Text.XML.Expat.Internal.Qualified
        • Text.XML.Expat.Namespaced
        • Text.XML.Expat.NodeClass
        • Text.XML.Expat.Proc
        • Text.XML.Expat.Qualified
        • Text.XML.Expat.SAX
        • Text.XML.Expat.Tree


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