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examples from various popular [[Libraries_and_tools|Haskell projects]].
 
examples from various popular [[Libraries_and_tools|Haskell projects]].
 
To start learning the language, good places to start are
 
To start learning the language, good places to start are
[[Learning_Haskell|here]], [[Haskell_in_5_steps|here]] and
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[[Learning Haskell]],
[[Books_and_tutorials|here]].
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[[Haskell in 5 steps]], and
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[[Books and tutorials]].
   
More code may be found [http://haskell.org/haskellwiki/Category:Code on the wiki].
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More code may be found [http://www.haskell.org/haskellwiki/Category:Code on the wiki].
   
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<!--
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Some lines are commented out for later update
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=== Library code ===
 
=== Library code ===
   
 
Library code usually differs from application code: it is often highly
 
Library code usually differs from application code: it is often highly
structured, and documented with [http://haskell.org/haddock/ haddock],
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structured, and documented with [http://www.haskell.org/haddock/ haddock],
 
and can be rather optimised. Some instructive examples (syntax
 
and can be rather optimised. Some instructive examples (syntax
 
highlighting by [http://www.cs.york.ac.uk/fp/darcs/hscolour/ hscolour]):
 
highlighting by [http://www.cs.york.ac.uk/fp/darcs/hscolour/ hscolour]):
   
* [http://www.cse.unsw.edu.au/~dons/data/Prelude.html A Haskell 98 Prelude.hs], foundational Haskell library ([http://www.cse.unsw.edu.au/~dons/data/Prelude.hs raw], [http://haskell.org/ghc/docs/latest/html/libraries/base/Prelude.html docs])
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* [http://www.haskell.org/ghc/docs/latest/html/libraries/base/src/Prelude.html A Haskell Prelude.hs], foundational Haskell library ([http://www.haskell.org/ghc/docs/latest/html/libraries/base/Prelude.html docs])
* [[Simple_unix_tools|Unix.hs]], simple unix tools, for beginner Haskellers ([http://www.cse.unsw.edu.au/~dons/data/Basics.hs raw])
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* [http://www.cse.unsw.edu.au/~dons/data/List.html List.hs], the standard list library ([http://www.cse.unsw.edu.au/~dons/data/List.hs raw], [http://haskell.org/ghc/docs/latest/html/libraries/base/Data-List.html docs])
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* [[Simple_Unix_tools | Unix.hs]], simple unix tools, for beginner Haskellers
* [http://www.cse.unsw.edu.au/~dons/data/Maybe.html Maybe.hs], the <code>Maybe</code> type ([http://www.cse.unsw.edu.au/~dons/data/Maybe.hs raw], [http://haskell.org/ghc/docs/latest/html/libraries/base/Data-Maybe.html docs])
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* [http://www.cse.unsw.edu.au/~dons/data/Map.html Map.hs], the standard finite map ([http://darcs.haskell.org/packages/base/Data/Map.hs raw], [http://haskell.org/ghc/docs/latest/html/libraries/base/Data-Map.html docs])
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* [http://hackage.haskell.org/packages/archive/base/latest/doc/html/src/Data-List.html List.hs], the standard list library ([http://hackage.haskell.org/packages/archive/base/latest/doc/html/Data-List.html docs])
* [http://www.cse.unsw.edu.au/~dons/data/Graph.html Graph.hs], a graph type ([http://darcs.haskell.org/packages/base/Data/Graph.hs raw], [http://haskell.org/ghc/docs/latest/html/libraries/base/Data-Graph.html docs])
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* [http://www.cse.unsw.edu.au/~dons/data/Monad.html Monad.hs], basic monad support ([http://darcs.haskell.org/packages/base/Control/Monad.hs raw], [http://haskell.org/ghc/docs/latest/html/libraries/base/Control-Monad.html docs])
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* [http://hackage.haskell.org/packages/archive/base/latest/doc/html/src/Data-Maybe.html Maybe.hs], the <code>Maybe</code> type ([http://hackage.haskell.org/packages/archive/base/latest/doc/html/Data-Maybe.html docs])
* [http://www.cse.unsw.edu.au/~dons/data/QuickCheck.html QuickCheck.hs], a testing framework ([http://darcs.haskell.org/packages/QuickCheck/Test/QuickCheck.hs raw], [http://haskell.org/ghc/docs/latest/html/libraries/QuickCheck/Test-QuickCheck.html docs])
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* [http://www.cse.unsw.edu.au/~dons/data/HughesPJ.html PrettyPrint.hs], a pretty printing library ([http://darcs.haskell.org/ghc-6.6/packages/base/Text/PrettyPrint/HughesPJ.hs raw], [http://haskell.org/ghc/docs/latest/html/libraries/base/Text-PrettyPrint-HughesPJ.html docs])
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* [http://hackage.haskell.org/packages/archive/containers/latest/doc/html/src/Data-Map.html Map.hs], the standard finite map ([http://www.haskell.org/ghc/docs/latest/html/libraries/containers-0.4.2.1/index.html docs])
* [http://www.cse.unsw.edu.au/~dons/data/State.html State.hs], a state monad ([http://darcs.haskell.org/packages/mtl/Control/Monad/State.hs raw], [http://haskell.org/ghc/docs/latest/html/libraries/mtl/Control-Monad-State-Lazy.html docs])
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* [http://www.cse.unsw.edu.au/~dons/data/Music.html Music.hs], a music composition system (literate latex-style Haskell) ([http://darcs.haskell.org/haskore/src/Haskore/Music.lhs raw], [http://haskell.org/haskore/ home])
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* [http://hackage.haskell.org/packages/archive/containers/latest/doc/html/src/Data-Graph.html Graph.hs], a graph type ([http://hackage.haskell.org/packages/archive/containers/latest/doc/html/Data-Graph.html docs])
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* [http://hackage.haskell.org/packages/archive/base/latest/doc/html/src/Control-Monad.html Monad.hs], basic monad support ([http://hackage.haskell.org/packages/archive/base/latest/doc/html/Control-Monad.html docs])
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* [http://code.haskell.org/QuickCheck/stable/Test/QuickCheck/ QuickCheck], a testing framework ([http://hackage.haskell.org/package/QuickCheck docs])
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* [http://hackage.haskell.org/packages/archive/pretty/latest/doc/html/src/Text-PrettyPrint-HughesPJ.html PrettyPrint.hs], a pretty printing library ([http://hackage.haskell.org/package/pretty docs])
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* [http://hackage.haskell.org/packages/archive/transformers/latest/doc/html/src/Control-Monad-Trans-State-Lazy.html State.hs], a state monad ([http://hackage.haskell.org/packages/archive/transformers/latest/doc/html/Control-Monad-Trans-State-Lazy.html docs])
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<!--
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* [http://www.cse.unsw.edu.au/~dons/data/Music.html Music.hs], a music composition system (literate latex-style Haskell) ([http://darcs.haskell.org/haskore/src/Haskore/Music.lhs raw], [http://www.haskell.org/haskore/ home])
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-->
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* [http://www.ninebynine.org/Software/Swish-0.2.1/HaskellRDF/Dfa/Dfa.lhs Dfa.lhs], finite automata (literate Bird-style Haskell)
 
* [http://www.ninebynine.org/Software/Swish-0.2.1/HaskellRDF/Dfa/Dfa.lhs Dfa.lhs], finite automata (literate Bird-style Haskell)
* [http://www.cse.unsw.edu.au/~dons/data/RedBlackTree.html RedBlackTree.hs], a red-black tree ([http://www.polyomino.f2s.com/david/haskell/hs/RedBlackTree.hs.txt raw])
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* [http://www.polyomino.f2s.com/david/haskell/hs/RedBlackTree.hs.txt RedBlackTree.hs], a red-black tree
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<!--
 
* [http://www.cse.unsw.edu.au/~dons/data/Prime.html Prime.hs], prime numbers ([http://andrew.bromage.org/darcs/numbertheory/Math/Prime.hs raw])
 
* [http://www.cse.unsw.edu.au/~dons/data/Prime.html Prime.hs], prime numbers ([http://andrew.bromage.org/darcs/numbertheory/Math/Prime.hs raw])
* [http://www.cse.unsw.edu.au/~dons/data/Foldable.html Foldable.hs], traversable data structures ([http://darcs.haskell.org/packages/base/Data/Foldable.hs raw])
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-->
* [http://www.cse.unsw.edu.au/~dons/data/ByteString.html ByteString.hs], high-performance string type ([http://darcs.haskell.org/packages/base/Data/ByteString.hs raw], [http://www.cse.unsw.edu.au/~dons/fps/Data-ByteString.html docs], [http://www.cse.unsw.edu.au/~dons/fps.html home])
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* [http://www.cse.unsw.edu.au/~dons/data/SmallCheck.html SmallCheck.hs], a testing framework ([http://www.cse.unsw.edu.au/~dons/code/lambdabot/scripts/SmallCheck.hs raw])
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* [http://hackage.haskell.org/packages/archive/base/latest/doc/html/src/Data-Foldable.html Foldable.hs], traversable data structures ([http://hackage.haskell.org/packages/archive/base/latest/doc/html/Data-Foldable.html docs])
* [http://haskell.org/haskellwiki/Darcs_repositories More code ...]
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* [http://www.haskell.org/ghc/docs/latest/html/libraries/bytestring/src/Data-ByteString.html ByteString.hs], high-performance string type ([http://code.haskell.org/bytestring/Data/ByteString.hs raw], [http://hackage.haskell.org/package/bytestring docs])
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* [https://github.com/feuerbach/smallcheck/blob/master/Test/SmallCheck.hs SmallCheck.hs], a testing framework ([https://raw.github.com/feuerbach/smallcheck/master/Test/SmallCheck.hs raw], [http://hackage.haskell.org/package/smallcheck docs])
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* [http://www.haskell.org/haskellwiki/Darcs_repositories More code ...]
   
 
=== Application code ===
 
=== Application code ===
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monadic IO, and sometimes other advanced features such as concurrency:
 
monadic IO, and sometimes other advanced features such as concurrency:
   
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<!--
 
* [http://nanardon.zarb.org/darcs/darcs/PatchCommute.lhs Darcs], a revision control system (uses literate latex Haskell style) ([http://darcs.net home])
 
* [http://nanardon.zarb.org/darcs/darcs/PatchCommute.lhs Darcs], a revision control system (uses literate latex Haskell style) ([http://darcs.net home])
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-->
 
* [http://svn.openfoundry.org/pugs/src/Pugs/Eval.hs Pugs], a perl6 implementation ([http://pugscode.org home])
 
* [http://svn.openfoundry.org/pugs/src/Pugs/Eval.hs Pugs], a perl6 implementation ([http://pugscode.org home])
* [http://www.cse.unsw.edu.au/~dons/code/yi/Yi/Core.hs Yi], a text editor, ([http://www.cse.unsw.edu.au/~dons/yi.html home])
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* [http://j.mongers.org/pub/haskell/darcs/conjure/Conjure/Torrent.hs Conjure], a bittorrent client
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* [https://github.com/yi-editor/yi/blob/master/yi/src/library/Yi/Core.hs Yi], a text editor, ([http://www.haskell.org/haskellwiki/Yi home], [https://raw.github.com/yi-editor/yi/master/yi/src/library/Yi/Core.hs raw, [http://hackage.haskell.org/package/yi doc])
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<!--
 
* [http://darcs.haskell.org/~lemmih/downNova/src/Torrent.hs DownNova], a file downloading program
 
* [http://darcs.haskell.org/~lemmih/downNova/src/Torrent.hs DownNova], a file downloading program
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-->
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* [http://www.cs.york.ac.uk/fp/darcs/cpphs/Language/Preprocessor/Cpphs/Tokenise.hs cpphs], an implementation of the C preprocessor ([http://www.cs.york.ac.uk/fp/cpphs/ home])
 
* [http://www.cs.york.ac.uk/fp/darcs/cpphs/Language/Preprocessor/Cpphs/Tokenise.hs cpphs], an implementation of the C preprocessor ([http://www.cs.york.ac.uk/fp/cpphs/ home])
* [http://darcs.haskell.org/ghc/compiler/simplCore/Simplify.lhs GHC], a Haskell compiler (literate latex style) ([http://haskell.org/ghc/ home])
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* [http://www.augustsson.net/Darcs/Djinn/LJT.hs Djinn], a theorem prover ([http://darcs.augustsson.net/Darcs/Djinn/ home])
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* [http://darcs.haskell.org/ghc/compiler/simplCore/Simplify.lhs GHC], a Haskell compiler (literate latex style) ([http://www.haskell.org/ghc/ home])
* [http://darcs.haskell.org/c2hs/c2hs/c/CTrav.hs c2hs], a C to Haskell interface generator ([http://www.cse.unsw.edu.au/~chak/haskell/c2hs/ home])
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* [http://www.cse.unsw.edu.au/~dons/code/lambdabot/LBState.hs Lambdabot], an IRC bot ([http://www.cse.unsw.edu.au/~dons/lambdabot.html home])
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* [http://darcs.augustsson.net/Darcs/Djinn/Djinn/LJT.hs Djinn], a theorem prover ([http://darcs.augustsson.net/Darcs/Djinn/ home])
* [http://www.cse.unsw.edu.au/~dons/code/hmp3/Core.hs hmp3], an curses mp3 player ([http://www.cse.unsw.edu.au/~dons/hmp3.html home])
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* [http://haskell.org/haskellwiki/Darcs_repositories More code ...]
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* [http://code.haskell.org/c2hs/src/C2HS/C/Trav.hs c2hs], a C to Haskell interface generator ([http://www.cse.unsw.edu.au/~chak/haskell/c2hs/ home])
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* [http://code.haskell.org/lambdabot/LBState.hs Lambdabot], an IRC bot ([http://www.haskell.org/haskellwiki/Lambdabot home])
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* [http://code.haskell.org/~dons/code/hmp3/Core.hs hmp3], a curses mp3 player
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* [http://www.haskell.org/haskellwiki/Darcs_repositories More code ...]
   
 
== Examples ==
 
== Examples ==
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; [[Tying the Knot]] : An example that illustrates different ways to define recursive data structures. The example defines a simple language (illustrating how to define some recursive structures) and an interpreter for the language (illustrating how to work with the recursive structures).
 
; [[Tying the Knot]] : An example that illustrates different ways to define recursive data structures. The example defines a simple language (illustrating how to define some recursive structures) and an interpreter for the language (illustrating how to work with the recursive structures).
   
; [http://members.chello.nl/hjgtuyl/tourdemonad.html A tour of the Haskell Monad functions] : Small usage examples of the basic Haskell monad functions
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; [http://members.chello.nl/hjgtuyl/tourdemonad.html A tour of the Haskell Monad functions]: Small usage examples of the basic Haskell monad functions
   
 
[[Category:Code]]
 
[[Category:Code]]

Latest revision as of 16:05, 26 February 2012

To get a feel for what real world Haskell looks like, here are some examples from various popular Haskell projects. To start learning the language, good places to start are Learning Haskell, Haskell in 5 steps, and Books and tutorials.

More code may be found on the wiki.


[edit] 1 Library code

Library code usually differs from application code: it is often highly structured, and documented with haddock, and can be rather optimised. Some instructive examples (syntax highlighting by hscolour):

  • Unix.hs, simple unix tools, for beginner Haskellers
  • Dfa.lhs, finite automata (literate Bird-style Haskell)

[edit] 2 Application code

Code from popular Haskell applications. Such code often makes use of a monadic IO, and sometimes other advanced features such as concurrency:

  • cpphs, an implementation of the C preprocessor (home)
  • GHC, a Haskell compiler (literate latex style) (home)
  • c2hs, a C to Haskell interface generator (home)
  • hmp3, a curses mp3 player

[edit] 3 Examples

Tying the Knot 
An example that illustrates different ways to define recursive data structures. The example defines a simple language (illustrating how to define some recursive structures) and an interpreter for the language (illustrating how to work with the recursive structures).
A tour of the Haskell Monad functions
Small usage examples of the basic Haskell monad functions