Difference between revisions of "Example code"
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To get a feel for what real world Haskell looks like, here are some |
To get a feel for what real world Haskell looks like, here are some |
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| − | examples from various popular Haskell projects. |
+ | examples from various popular [[Libraries_and_tools|Haskell projects]]. |
| + | To start learning the language, good places to start are |
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| + | [[Learning Haskell]], |
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| + | [[Haskell in 5 steps]], and |
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| + | [[Books and tutorials]]. |
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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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| + | --> |
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=== Library code === |
=== Library code === |
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Library code usually differs from application code: it is often highly |
Library code usually differs from application code: it is often highly |
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| − | structured, and documented with [http://haskell.org/haddock haddock], |
+ | structured, and documented with [http://www.haskell.org/haddock/ haddock], |
| − | and can be rather optimised. Some instructive examples |
+ | and can be rather optimised. Some instructive examples (syntax |
| + | highlighting by [http://www.cs.york.ac.uk/fp/darcs/hscolour/ hscolour]): |
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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]) |
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| + | |||
| + | * [[Simple_Unix_tools | Unix.hs]], simple unix tools, for beginner Haskellers |
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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]) |
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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]) |
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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]) |
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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://darcs.haskell.org/packages/base/Data/List.hs List.hs], the standard [a] type |
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| − | * [http://www.cse.unsw.edu.au/~dons/data/Prelude.hs A Haskell98 Prelude.hs], foundational Haskell library |
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| − | * [http://darcs.haskell.org/packages/base/Data/Maybe.hs Maybe.hs], the Maybe a type |
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| − | * [http://darcs.haskell.org/packages/base/Data/Map.hs Map.hs], the standard finite map |
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| − | * [http://darcs.haskell.org/packages/base/Data/Tree.hs Tree.hs], a tree type |
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| − | * [http://darcs.haskell.org/packages/base/Data/Graph.hs Graph.hs], a graph type |
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| − | * [http://darcs.haskell.org/packages/base/Control/Monad.hs Monad.hs], basic monadic support |
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| − | * [http://darcs.haskell.org/packages/QuickCheck/Test/QuickCheck.hs QuickCheck.hs], a testing framework |
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| − | * [http://darcs.haskell.org/packages/base/Text/PrettyPrint/HughesPJ.hs PrettyPrint.hs], a pretty printing library |
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| − | * [http://darcs.haskell.org/packages/monads/Monad/StateT.hs StateT.hs], a monad transformer library |
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| − | * [http://darcs.haskell.org/haskore/src/Haskore/Music.lhs Music.lhs], a music composition system (literate latex-style Haskell) |
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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) |
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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:// |
+ | * [http://www.polyomino.f2s.com/david/haskell/hs/RedBlackTree.hs.txt RedBlackTree.hs], a red-black tree |
| + | <!-- |
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| − | * [http://darcs.haskell.org/packages/base/Data/Foldable.hs Foldable.hs], traversable data structures |
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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]) |
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| − | * [http://darcs.haskell.org/packages/base/Data/ByteString.hs ByteString.hs], high-performance string type |
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| + | --> |
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| − | * [http://darcs.haskell.org/packages/ndp/Data/Array/Parallel/Stream/Flat/Combinators.hs Combinators.hs], array combinators |
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| + | |||
| − | * [http://www.cse.unsw.edu.au/~dons/code/lambdabot/scripts/SmallCheck.hs SmallCheck.hs], a testing framework |
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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]) |
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| − | * [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 ...] |
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=== Application code === |
=== Application code === |
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| Line 33: | Line 62: | ||
monadic IO, and sometimes other advanced features such as concurrency: |
monadic IO, and sometimes other advanced features such as concurrency: |
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| + | <!-- |
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| − | * [http://www.abridgegame.org/repos/darcs-unstable/PatchCommute.lhs Darcs], a revision control system (uses literate latex Haskell style) |
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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]) |
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| − | * [http://svn.openfoundry.org/pugs/src/Pugs/Eval.hs Pugs], a perl6 implementation |
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| + | --> |
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| − | * [http://www.cse.unsw.edu.au/~dons/code/yi/Yi/Core.hs Yi], a text editor |
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| − | * [http:// |
+ | * [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]) |
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| + | <!-- |
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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 |
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| + | |||
| − | * [http://darcs.haskell.org/ghc/compiler/simplCore/Simplify.lhs GHC], a Haskell compiler (literate latex style) |
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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]) |
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| − | * [http://www.augustsson.net/Darcs/Djinn/LJT.hs Djinn], a theorem prover |
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| + | |||
| − | * [http://darcs.haskell.org/c2hs/c2hs/c/CTrav.hs c2hs], a C to Haskell interface generator |
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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]) |
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| − | * [http://www.cse.unsw.edu.au/~dons/code/lambdabot/LBState.hs Lambdabot], an IRC bot |
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| + | |||
| − | * [http://www.cse.unsw.edu.au/~dons/code/hmp3/Core.hs hmp3], an curses mp3 player |
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| + | * [http://darcs.augustsson.net/Darcs/Djinn/Djinn/LJT.hs Djinn], a theorem prover ([http://darcs.augustsson.net/Darcs/Djinn/ 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 ...] |
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| − | + | == 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). |
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| − | Here is a list of other random code collected on this wiki, replacing |
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| − | [http://haskell.org/hawiki/CodeOnTheWiki CodeOnTheWiki]. Contributors |
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| − | of code to the old area are encouraged to bring their code over here. |
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| − | This should only be done by the original author because anything on |
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| − | these pages is automatically licensed under the Simple Permissive |
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| − | License ([[HaskellWiki:Copyrights]]). |
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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 |
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| − | Most examples are roughly intermediate to advanced in difficulty. |
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| + | [[Category:Code]] |
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| − | * [[Prelude extensions]]: Simple things you've always wished were in the Prelude. |
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| − | * [[Gallery]]: Complete small programs. |
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| − | * [[Blow_your_mind|Blow your mind]]: Short, useful, cool, magical examples, which should incite the reader's curiosity and (hopefully) lead him to a deeper understanding of advanced Haskell concepts. |
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| − | * [[Sudoku]]: Solvers for popular puzzle [http://en.wikipedia.org/wiki/Sudoku Sudoku] |
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| − | * [[NewMonads]]: Useful monads that are not in the main library. |
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| − | * [[PrincipalVariationSearch]]: Principal variation search |
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| − | * [http://haskell.org/hawiki/ShootoutEntry Shootout Entries]: Examples still on the old wiki for the [http://shootout.alioth.debian.org/index.php The Computer Language Shootout Benchmarks]. |
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| − | * [http://www.informatik.uni-bonn.de/~ralf/ Ralf Hinze] maintains a [http://www.informatik.uni-bonn.de/~ralf/software.html Haskell software page] |
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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.
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):
- A Haskell Prelude.hs, foundational Haskell library (docs)
- Unix.hs, simple unix tools, for beginner Haskellers
- QuickCheck, a testing framework (docs)
- PrettyPrint.hs, a pretty printing library (docs)
- Dfa.lhs, finite automata (literate Bird-style Haskell)
- RedBlackTree.hs, a red-black tree
- Foldable.hs, traversable data structures (docs)
- ByteString.hs, high-performance string type (raw, docs)
- SmallCheck.hs, a testing framework (raw, docs)
Application code
Code from popular Haskell applications. Such code often makes use of a monadic IO, and sometimes other advanced features such as concurrency:
- Yi, a text editor, (home, raw, [http://hackage.haskell.org/package/yi doc)
- 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