Difference between revisions of "Prelude"
MichalPalka (talk | contribs) (Add an article on prelude an avoiding its automatic import) |
MichalPalka (talk | contribs) m (Capitalize Prelude everywhere) |
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The documentation of prelude from [[GHC]] can be found [http://www.haskell.org/ghc/docs/latest/html/libraries/base/Prelude.html here]. |
The documentation of prelude from [[GHC]] can be found [http://www.haskell.org/ghc/docs/latest/html/libraries/base/Prelude.html here]. |
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| − | ==Avoiding |
+ | ==Avoiding Prelude== |
If you wish to program without a prelude or to use a custom version of it you can suppress its automatic inclusion in several ways. |
If you wish to program without a prelude or to use a custom version of it you can suppress its automatic inclusion in several ways. |
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===Explicit import decalration=== |
===Explicit import decalration=== |
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| − | By including an explicit import declaration of |
+ | By including an explicit import declaration of Prelude as follows |
<haskell> |
<haskell> |
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import Prelude () |
import Prelude () |
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The empty import list in the parenthesis causes nothing to be imported while the automatic import is prevented as well. |
The empty import list in the parenthesis causes nothing to be imported while the automatic import is prevented as well. |
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===Language option=== |
===Language option=== |
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| − | [[GHC]] supports a [http://www.haskell.org/ghc/docs/latest/html/users_guide/ghc-language-features.html#options-language language option] -XNoImplicitPrelude (or -fno-implicit-prelude in older [[GHC]]) that makes it not import |
+ | [[GHC]] supports a [http://www.haskell.org/ghc/docs/latest/html/users_guide/ghc-language-features.html#options-language language option] -XNoImplicitPrelude (or -fno-implicit-prelude in older [[GHC]]) that makes it not import Prelude implicitly. The option can be also specified by adding: |
<haskell> |
<haskell> |
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{-# LANGUAGE NoImplicitPrelude #-} |
{-# LANGUAGE NoImplicitPrelude #-} |
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Revision as of 19:34, 11 January 2008
Prelude is a module that contains a small set of standard definitions and is included automatically into all Haskell modules.
Documentation
The documentation of prelude from GHC can be found here.
Avoiding Prelude
If you wish to program without a prelude or to use a custom version of it you can suppress its automatic inclusion in several ways.
Explicit import decalration
By including an explicit import declaration of Prelude as follows
import Prelude ()
The empty import list in the parenthesis causes nothing to be imported while the automatic import is prevented as well.
Language option
GHC supports a language option -XNoImplicitPrelude (or -fno-implicit-prelude in older GHC) that makes it not import Prelude implicitly. The option can be also specified by adding:
{-# LANGUAGE NoImplicitPrelude #-}
on top of the module.
This option makes it possible to rebind the monadic do syntax.