Personal tools

Example code

From HaskellWiki

(Difference between revisions)
Jump to: navigation, search
(Changed haskell.org to www.haskell.org, to avoid messages from the link checker)
(Obsolete links removed, commented out, or updated (more to do))
Line 16: Line 16:
 
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://www.haskell.org/ghc/docs/latest/html/libraries/base/Prelude.html docs])
+
* [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])
+
* [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://www.haskell.org/ghc/docs/latest/html/libraries/base/Data-List.html docs])
+
* [[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://www.haskell.org/ghc/docs/latest/html/libraries/base/Data-Maybe.html docs])
+
* [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://www.haskell.org/ghc/docs/latest/html/libraries/base/Data-Map.html docs])
+
* [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://www.haskell.org/ghc/docs/latest/html/libraries/base/Data-Graph.html docs])
+
* [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://www.haskell.org/ghc/docs/latest/html/libraries/base/Control-Monad.html docs])
+
* [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://www.haskell.org/ghc/docs/latest/html/libraries/QuickCheck/Test-QuickCheck.html docs])
+
* [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://www.haskell.org/ghc/docs/latest/html/libraries/base/Text-PrettyPrint-HughesPJ.html docs])
+
* [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://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])
  +
  +
* [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])
  +
  +
* [http://code.haskell.org/QuickCheck/stable/Test/QuickCheck/ QuickCheck], a testing framework ([http://hackage.haskell.org/package/QuickCheck docs])
  +
  +
* [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])
  +
<!--
 
* [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://www.haskell.org/ghc/docs/latest/html/libraries/mtl/Control-Monad-State-Lazy.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://www.haskell.org/ghc/docs/latest/html/libraries/mtl/Control-Monad-State-Lazy.html docs])
  +
-->
  +
<!--
 
* [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])
 
* [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])
  +
-->
 
* [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])
+
  +
* [http://www.polyomino.f2s.com/david/haskell/hs/RedBlackTree.hs.txt], a red-black tree
  +
 
* [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])
 
* [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])
* [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])
+
  +
* [http://www.haskell.org/ghc/docs/latest/html/libraries/bytestring/src/Data-ByteString.html ByteString.hs], high-performance string type ([http://darcs.haskell.org/packages/bytestring/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])
  +
 
* [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])
 
* [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])
  +
 
* [http://www.haskell.org/haskellwiki/Darcs_repositories More code ...]
 
* [http://www.haskell.org/haskellwiki/Darcs_repositories More code ...]
   
Line 40: Line 45:
 
monadic IO, and sometimes other advanced features such as concurrency:
 
monadic IO, and sometimes other advanced features such as concurrency:
   
  +
<!--
 
* [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])
  +
-->
 
* [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])
 
* [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])
 
* [http://j.mongers.org/pub/haskell/darcs/conjure/Conjure/Torrent.hs Conjure], a bittorrent client
 
* [http://j.mongers.org/pub/haskell/darcs/conjure/Conjure/Torrent.hs Conjure], a bittorrent client
  +
<!--
 
* [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
  +
-->
 
* [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://www.haskell.org/ghc/ home])
 
* [http://darcs.haskell.org/ghc/compiler/simplCore/Simplify.lhs GHC], a Haskell compiler (literate latex style) ([http://www.haskell.org/ghc/ home])
* [http://www.augustsson.net/Darcs/Djinn/LJT.hs Djinn], a theorem prover ([http://darcs.augustsson.net/Darcs/Djinn/ home])
+
* [http://darcs.augustsson.net/Darcs/Djinn/Djinn/LJT.hs Djinn], a theorem prover ([http://darcs.augustsson.net/Darcs/Djinn/ 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])
+
* [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])
 
* [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])
 
* [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])
 
* [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])
 
* [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])

Revision as of 19:57, 25 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.


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
  • [1], a red-black tree

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:

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