Difference between revisions of "Example code"

From HaskellWiki
Jump to navigation Jump to search
(More link updating)
m (Fix broken link for c2hs home (site moved))
(6 intermediate revisions by 3 users not shown)
Line 23: Line 23:
 
* [[Simple_Unix_tools | Unix.hs]], simple unix tools, for beginner Haskellers
 
* [[Simple_Unix_tools | Unix.hs]], simple unix tools, for beginner Haskellers
   
* [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://hackage.haskell.org/packages/archive/base/latest/doc/html/src/Data.List.html Data.List], the standard list library ([http://hackage.haskell.org/packages/archive/base/latest/doc/html/Data-List.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://hackage.haskell.org/packages/archive/base/latest/doc/html/src/Data.Maybe.html Data.Maybe], the <code>Maybe</code> type ([http://hackage.haskell.org/packages/archive/base/latest/doc/html/Data-Maybe.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.Map.html Data.Map], 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/containers/latest/doc/html/src/Data.Graph.html Data.Graph], 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://hackage.haskell.org/packages/archive/base/latest/doc/html/src/Control.Monad.html Control.Monad], 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])
+
* [https://github.com/nick8325/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://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://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])
+
* [http://hackage.haskell.org/packages/archive/transformers/latest/doc/html/src/Control-Monad-Trans-State-Lazy.html Control.Monad.Trans.State.Lazy], a state monad ([http://hackage.haskell.org/packages/archive/transformers/latest/doc/html/Control-Monad-Trans-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.polyomino.f2s.com/david/haskell/hs/RedBlackTree.hs.txt], a red-black tree
+
* [http://www.polyomino.f2s.com/david/haskell/hs/RedBlackTree.hs.txt RedBlackTree.hs], 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://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://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])
+
* [http://hackage.haskell.org/packages/archive/base/latest/doc/html/src/Data.Foldable.html Data.Foldable], traversable data structures ([http://hackage.haskell.org/packages/archive/base/latest/doc/html/Data-Foldable.html docs])
   
* [https://github.com/feuerbach/smallcheck/blob/master/Test/SmallCheck.hs], a testing framework ([https://raw.github.com/feuerbach/smallcheck/master/Test/SmallCheck.hs raw], [http://hackage.haskell.org/package/smallcheck docs])
+
* [https://github.com/haskell/bytestring Data.ByteString], high-performance string type ([http://code.haskell.org/bytestring/Data/ByteString.hs raw], [http://hackage.haskell.org/package/bytestring docs])
  +
  +
* [https://github.com/feuerbach/smallcheck SmallCheck], a testing framework ([https://raw.github.com/feuerbach/smallcheck/master/Test/SmallCheck.hs raw], [http://hackage.haskell.org/package/smallcheck docs])
   
 
* [http://www.haskell.org/haskellwiki/Darcs_repositories More code ...]
 
* [http://www.haskell.org/haskellwiki/Darcs_repositories More code ...]
 
   
 
=== Application code ===
 
=== Application code ===
Line 66: Line 67:
 
* [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])
   
* [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])
+
* [https://github.com/yi-editor/yi/blob/master/yi-core/src/Yi/Core.hs Yi], a text editor, ([http://www.haskell.org/haskellwiki/Yi home], [https://raw.githubusercontent.com/yi-editor/yi/master/yi-core/src/Yi/Core.hs raw], [http://hackage.haskell.org/package/yi doc])
 
* [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 ([https://archives.haskell.org/projects.haskell.org/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])
Line 78: Line 78:
 
* [http://darcs.augustsson.net/Darcs/Djinn/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://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://code.haskell.org/c2hs/src/C2HS/C/Trav.hs c2hs], a C to Haskell interface generator ([https://github.com/haskell/c2hs home])
   
 
* [http://code.haskell.org/lambdabot/LBState.hs Lambdabot], an IRC bot ([http://www.haskell.org/haskellwiki/Lambdabot home])
 
* [http://code.haskell.org/lambdabot/LBState.hs Lambdabot], an IRC bot ([http://www.haskell.org/haskellwiki/Lambdabot home])
Line 85: Line 85:
   
 
* [http://www.haskell.org/haskellwiki/Darcs_repositories More code ...]
 
* [http://www.haskell.org/haskellwiki/Darcs_repositories More code ...]
 
   
 
== Examples ==
 
== Examples ==

Revision as of 09:43, 21 October 2019

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.


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)

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

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