haddock: A documentation-generation tool for Haskell libraries

[ bsd3, documentation, program ] [ Propose Tags ]

This is Haddock, a tool for automatically generating documentation from annotated Haskell source code. It is primary intended for documenting library interfaces, but it should be useful for any kind of Haskell code.

Haddock lets you write documentation annotations next to the definitions of functions and types in the source code, in a syntax that is easy on the eye when writing the source code (no heavyweight mark-up).

Haddock understands Haskell's module system, so you can structure your code however you like without worrying that internal structure will be exposed in the generated documentation. For example, it is common to implement a library in several modules, but define the external API by having a single module which re-exports parts of these implementation modules. Using Haddock, you can still write documentation annotations next to the actual definitions of the functions and types in the library, but the documentation annotations from the implementation will be propagated to the external API when the documentation is generated. Abstract types and classes are handled correctly. In fact, even without any documentation annotations, Haddock can generate useful documentation from your source code.

Documentation for the haddock binary is available at readthedocs.

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Versions [RSS] 0.8, 0.9,, 2.1.0, 2.2.0, 2.2.1, 2.2.2, 2.4.0, 2.4.1, 2.4.2, 2.5.0, 2.6.0, 2.6.1, 2.7.0, 2.7.1, 2.7.2, 2.8.0, 2.8.1, 2.9.0, 2.9.1, 2.9.2, 2.9.3, 2.9.4, 2.10.0, 2.11.0, 2.11.1, 2.12.0, 2.13.0, 2.13.1, 2.13.2,, 2.14.1, 2.14.2, 2.14.3, 2.15.0,,, 2.16.0, 2.16.1, 2.17.2, 2.17.4, 2.17.5, 2.18.1,, 2.20.0, 2.21.0, 2.22.0, 2.23.0, 2.23.1, 2.24.0, 2.24.1, 2.24.2, 2.25.0, 2.25.1, 2.26.0, 2.27.0, 2.28.0, 2.29.0, 2.29.1
Change log CHANGES.md
Dependencies base (>= && <4.15), haddock-api (==2.24.2) [details]
License BSD-3-Clause
Copyright (c) Simon Marlow, David Waern
Author Simon Marlow, David Waern
Maintainer Alec Theriault <alec.theriault@gmail.com>, Alex Biehl <alexbiehl@gmail.com>, Simon Hengel <sol@typeful.net>, Mateusz Kowalczyk <fuuzetsu@fuuzetsu.co.uk>
Category Documentation
Home page http://www.haskell.org/haddock/
Bug tracker https://github.com/haskell/haddock/issues
Source repo head: git clone https://github.com/haskell/haddock.git
Uploaded by alexbiehl at 2021-03-26T08:17:43Z
Distributions Arch:2.26.0, FreeBSD:2.16.1
Reverse Dependencies 10 direct, 17 indirect [details]
Executables haddock
Downloads 91163 total (191 in the last 30 days)
Rating 2.25 (votes: 2) [estimated by Bayesian average]
Your Rating
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Status Docs not available [build log]
Last success reported on 2021-03-26 [all 2 reports]

Readme for haddock-2.24.2

[back to package description]

Haddock CI Hackage

Haddock is the standard tool for generating documentation from Haskell code. Full documentation about Haddock itself can be found in the doc/ subdirectory, in reStructedText format format.

Project overview

This project consists of three packages:

  • haddock: provides the haddock executable. It is implemented as a tiny wrapper around haddock-api's Documentation.Haddock.haddock function.

  • haddock-api: contains the program logic of the haddock tool. The haddocks for the Documentation.Haddock module offer a good overview of the functionality.

  • haddock-library: is concerned with the parsing and processing of the Haddock markup language. Unlike the other packages, it is expected to build on a fairly wide range of GHC versions.


Please create issues when you have any problems and pull requests if you have some code.


To get started you'll need the latest GHC release installed.

Clone the repository:

git clone https://github.com/haskell/haddock.git
cd haddock

and then proceed using your favourite build tool.

Note: before building haddock, you need to build the subprojects haddock-library and haddock-api, in this order! The cabal v2-build takes care of this automatically.

Using cabal v2-build

cabal v2-build -w ghc-8.10.1
cabal v2-test -w ghc-8.10.1 all

Using stack

stack init
stack build
export HADDOCK_PATH="$(stack exec which haddock)"
stack test

Using Cabal sandboxes (deprecated)

cabal sandbox init
cabal sandbox add-source haddock-library
cabal sandbox add-source haddock-api
cabal sandbox add-source haddock-test
# adjust -j to the number of cores you want to use
cabal install -j4 --dependencies-only --enable-tests
cabal configure --enable-tests
cabal build -j4
# run the test suite
export HADDOCK_PATH="dist/build/haddock/haddock"
cabal test

Git Branches

If you're a GHC developer and want to update Haddock to work with your changes, you should be working on the ghc-head branch. See instructions at https://gitlab.haskell.org/ghc/ghc/-/wikis/working-conventions/git/submodules for an example workflow.

Updating golden testsuite outputs

If you've changed Haddock's output, you will probably need to accept the new output of Haddock's golden test suites (html-test, latex-test, hoogle-test, and hypsrc-test). This can be done by passing the --accept argument to these test suites. With a new enough version of cabal-install:

cabal v2-test html-test latex-test hoogle-test hypsrc-test \