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</script></head><body><div id="package-header"><ul class="links" id="page-menu"><li><a href="src/Control-Monad-Logic.html">Source</a></li><li><a href="index.html">Contents</a></li><li><a href="doc-index.html">Index</a></li></ul><p class="caption">logict-0.6: A backtracking logic-programming monad.</p></div><div id="content"><div id="module-header"><table class="info"><tr><th>Portability</th><td>non-portable (multi-parameter type classes)</td></tr><tr><th>Stability</th><td>experimental</td></tr><tr><th>Maintainer</th><td>dan.doel@gmail.com</td></tr><tr><th>Safe Haskell</th><td>Safe-Infered</td></tr></table><p class="caption">Control.Monad.Logic</p></div><div id="table-of-contents"><p class="caption">Contents</p><ul><li><a href="#g:1">The Logic monad
</a></li><li><a href="#g:2">The LogicT monad transformer
</a></li></ul></div><div id="description"><p class="caption">Description</p><div class="doc"><p>A backtracking, logic programming monad.
</p><p>Adapted from the paper
/Backtracking, Interleaving, and Terminating
Monad Transformers/, by
Oleg Kiselyov, Chung-chieh Shan, Daniel P. Friedman, Amr Sabry
(<a href="http://www.cs.rutgers.edu/~ccshan/logicprog/LogicT-icfp2005.pdf">http://www.cs.rutgers.edu/~ccshan/logicprog/LogicT-icfp2005.pdf</a>).
</p></div></div><div id="synopsis"><p id="control.syn" class="caption expander" onclick="toggleSection('syn')">Synopsis</p><ul id="section.syn" class="hide" onclick="toggleSection('syn')"><li class="src short">module <a href="Control-Monad-Logic-Class.html">Control.Monad.Logic.Class</a></li><li class="src short"><span class="keyword">type</span> <a href="#t:Logic">Logic</a> = <a href="Control-Monad-Logic.html#t:LogicT">LogicT</a> <a href="/usr/share/doc/ghc/html/libraries/transformers-0.3.0.0/Data-Functor-Identity.html#t:Identity">Identity</a></li><li class="src short"><a href="#v:logic">logic</a> :: (<span class="keyword">forall</span> r. (a -> r -> r) -> r -> r) -> <a href="Control-Monad-Logic.html#t:Logic">Logic</a> a</li><li class="src short"><a href="#v:runLogic">runLogic</a> :: <a href="Control-Monad-Logic.html#t:Logic">Logic</a> a -> (a -> r -> r) -> r -> r</li><li class="src short"><a href="#v:observe">observe</a> :: <a href="Control-Monad-Logic.html#t:Logic">Logic</a> a -> a</li><li class="src short"><a href="#v:observeMany">observeMany</a> :: <a href="/usr/share/doc/ghc/html/libraries/base-4.5.0.0/Data-Int.html#t:Int">Int</a> -> <a href="Control-Monad-Logic.html#t:Logic">Logic</a> a -> [a]</li><li class="src short"><a href="#v:observeAll">observeAll</a> :: <a href="Control-Monad-Logic.html#t:Logic">Logic</a> a -> [a]</li><li class="src short"><span class="keyword">newtype</span> <a href="#t:LogicT">LogicT</a> m a = <a href="#v:LogicT">LogicT</a> {<ul class="subs"><li><a href="#v:unLogicT">unLogicT</a> :: <span class="keyword">forall</span> r. (a -> m r -> m r) -> m r -> m r</li></ul>}</li><li class="src short"><a href="#v:runLogicT">runLogicT</a> :: <a href="Control-Monad-Logic.html#t:LogicT">LogicT</a> m a -> (a -> m r -> m r) -> m r -> m r</li><li class="src short"><a href="#v:observeT">observeT</a> :: <a href="/usr/share/doc/ghc/html/libraries/base-4.5.0.0/Control-Monad.html#t:Monad">Monad</a> m => <a href="Control-Monad-Logic.html#t:LogicT">LogicT</a> m a -> m a</li><li class="src short"><a href="#v:observeManyT">observeManyT</a> :: <a href="/usr/share/doc/ghc/html/libraries/base-4.5.0.0/Control-Monad.html#t:Monad">Monad</a> m => <a href="/usr/share/doc/ghc/html/libraries/base-4.5.0.0/Data-Int.html#t:Int">Int</a> -> <a href="Control-Monad-Logic.html#t:LogicT">LogicT</a> m a -> m [a]</li><li class="src short"><a href="#v:observeAllT">observeAllT</a> :: <a href="/usr/share/doc/ghc/html/libraries/base-4.5.0.0/Control-Monad.html#t:Monad">Monad</a> m => <a href="Control-Monad-Logic.html#t:LogicT">LogicT</a> m a -> m [a]</li><li class="src short">module <a href="/usr/share/doc/ghc/html/libraries/base-4.5.0.0/Control-Monad.html">Control.Monad</a></li><li class="src short">module <a href="/usr/share/doc/ghc/html/libraries/mtl-2.1.1/Control-Monad-Trans.html">Control.Monad.Trans</a></li></ul></div><div id="interface"><h1>Documentation</h1><div class="top"><p class="src">module <a href="Control-Monad-Logic-Class.html">Control.Monad.Logic.Class</a></p></div><h1 id="g:1">The Logic monad
</h1><div class="top"><p class="src"><span class="keyword">type</span> <a name="t:Logic" class="def">Logic</a> = <a href="Control-Monad-Logic.html#t:LogicT">LogicT</a> <a href="/usr/share/doc/ghc/html/libraries/transformers-0.3.0.0/Data-Functor-Identity.html#t:Identity">Identity</a><a href="src/Control-Monad-Logic.html#Logic" class="link">Source</a></p><div class="doc"><p>The basic Logic monad, for performing backtracking computations
returning values of type <code>a</code>
</p></div></div><div class="top"><p class="src"><a name="v:logic" class="def">logic</a> :: (<span class="keyword">forall</span> r. (a -> r -> r) -> r -> r) -> <a href="Control-Monad-Logic.html#t:Logic">Logic</a> a<a href="src/Control-Monad-Logic.html#logic" class="link">Source</a></p><div class="doc"><p>A smart constructor for Logic computations.
</p></div></div><div class="top"><p class="src"><a name="v:runLogic" class="def">runLogic</a> :: <a href="Control-Monad-Logic.html#t:Logic">Logic</a> a -> (a -> r -> r) -> r -> r<a href="src/Control-Monad-Logic.html#runLogic" class="link">Source</a></p><div class="doc"><p>Runs a Logic computation with the specified initial success and
failure continuations.
</p></div></div><div class="top"><p class="src"><a name="v:observe" class="def">observe</a> :: <a href="Control-Monad-Logic.html#t:Logic">Logic</a> a -> a<a href="src/Control-Monad-Logic.html#observe" class="link">Source</a></p><div class="doc"><p>Extracts the first result from a Logic computation.
</p></div></div><div class="top"><p class="src"><a name="v:observeMany" class="def">observeMany</a> :: <a href="/usr/share/doc/ghc/html/libraries/base-4.5.0.0/Data-Int.html#t:Int">Int</a> -> <a href="Control-Monad-Logic.html#t:Logic">Logic</a> a -> [a]<a href="src/Control-Monad-Logic.html#observeMany" class="link">Source</a></p><div class="doc"><p>Extracts up to a given number of results from a Logic computation.
</p></div></div><div class="top"><p class="src"><a name="v:observeAll" class="def">observeAll</a> :: <a href="Control-Monad-Logic.html#t:Logic">Logic</a> a -> [a]<a href="src/Control-Monad-Logic.html#observeAll" class="link">Source</a></p><div class="doc"><p>Extracts all results from a Logic computation.
</p></div></div><h1 id="g:2">The LogicT monad transformer
</h1><div class="top"><p class="src"><span class="keyword">newtype</span> <a name="t:LogicT" class="def">LogicT</a> m a <a href="src/Control-Monad-Logic.html#LogicT" class="link">Source</a></p><div class="doc"><p>A monad transformer for performing backtracking computations
layered over another monad <code>m</code>
</p></div><div class="subs constructors"><p class="caption">Constructors</p><table><tr><td class="src"><a name="v:LogicT" class="def">LogicT</a></td><td class="doc empty"> </td></tr><tr><td colspan="2"><div class="subs fields"><p class="caption">Fields</p><dl><dt class="src"><a name="v:unLogicT" class="def">unLogicT</a> :: <span class="keyword">forall</span> r. (a -> m r -> m r) -> m r -> m r</dt><dd class="doc empty"> </dd></dl><div class="clear"></div></div></td></tr></table></div><div class="subs instances"><p id="control.i:LogicT" class="caption collapser" onclick="toggleSection('i:LogicT')">Instances</p><div id="section.i:LogicT" class="show"><table><tr><td class="src"><a href="/usr/share/doc/ghc/html/libraries/transformers-0.3.0.0/Control-Monad-Trans-Class.html#t:MonadTrans">MonadTrans</a> <a href="Control-Monad-Logic.html#t:LogicT">LogicT</a></td><td class="doc empty"> </td></tr><tr><td class="src"><a href="/usr/share/doc/ghc/html/libraries/mtl-2.1.1/Control-Monad-Error-Class.html#t:MonadError">MonadError</a> e m => <a href="/usr/share/doc/ghc/html/libraries/mtl-2.1.1/Control-Monad-Error-Class.html#t:MonadError">MonadError</a> e (<a href="Control-Monad-Logic.html#t:LogicT">LogicT</a> m)</td><td class="doc empty"> </td></tr><tr><td class="src"><a href="/usr/share/doc/ghc/html/libraries/mtl-2.1.1/Control-Monad-Reader-Class.html#t:MonadReader">MonadReader</a> r m => <a href="/usr/share/doc/ghc/html/libraries/mtl-2.1.1/Control-Monad-Reader-Class.html#t:MonadReader">MonadReader</a> r (<a href="Control-Monad-Logic.html#t:LogicT">LogicT</a> m)</td><td class="doc empty"> </td></tr><tr><td class="src"><a href="/usr/share/doc/ghc/html/libraries/mtl-2.1.1/Control-Monad-State-Class.html#t:MonadState">MonadState</a> s m => <a href="/usr/share/doc/ghc/html/libraries/mtl-2.1.1/Control-Monad-State-Class.html#t:MonadState">MonadState</a> s (<a href="Control-Monad-Logic.html#t:LogicT">LogicT</a> m)</td><td class="doc empty"> </td></tr><tr><td class="src"><a href="/usr/share/doc/ghc/html/libraries/base-4.5.0.0/Control-Monad.html#t:Monad">Monad</a> (<a href="Control-Monad-Logic.html#t:LogicT">LogicT</a> m)</td><td class="doc empty"> </td></tr><tr><td class="src"><a href="/usr/share/doc/ghc/html/libraries/base-4.5.0.0/Control-Monad.html#t:Functor">Functor</a> (<a href="Control-Monad-Logic.html#t:LogicT">LogicT</a> f)</td><td class="doc empty"> </td></tr><tr><td class="src"><a href="/usr/share/doc/ghc/html/libraries/base-4.5.0.0/Control-Monad.html#t:MonadPlus">MonadPlus</a> (<a href="Control-Monad-Logic.html#t:LogicT">LogicT</a> m)</td><td class="doc empty"> </td></tr><tr><td class="src"><a href="/usr/share/doc/ghc/html/libraries/base-4.5.0.0/Control-Applicative.html#t:Applicative">Applicative</a> (<a href="Control-Monad-Logic.html#t:LogicT">LogicT</a> f)</td><td class="doc empty"> </td></tr><tr><td class="src">(<a href="/usr/share/doc/ghc/html/libraries/base-4.5.0.0/Control-Monad.html#t:Monad">Monad</a> m, <a href="/usr/share/doc/ghc/html/libraries/base-4.5.0.0/Data-Foldable.html#t:Foldable">Foldable</a> m) => <a href="/usr/share/doc/ghc/html/libraries/base-4.5.0.0/Data-Foldable.html#t:Foldable">Foldable</a> (<a href="Control-Monad-Logic.html#t:LogicT">LogicT</a> m)</td><td class="doc empty"> </td></tr><tr><td class="src"><a href="/usr/share/doc/ghc/html/libraries/base-4.5.0.0/Data-Traversable.html#t:Traversable">Traversable</a> (<a href="Control-Monad-Logic.html#t:LogicT">LogicT</a> <a href="/usr/share/doc/ghc/html/libraries/transformers-0.3.0.0/Data-Functor-Identity.html#t:Identity">Identity</a>)</td><td class="doc empty"> </td></tr><tr><td class="src"><a href="/usr/share/doc/ghc/html/libraries/base-4.5.0.0/Control-Applicative.html#t:Alternative">Alternative</a> (<a href="Control-Monad-Logic.html#t:LogicT">LogicT</a> f)</td><td class="doc empty"> </td></tr><tr><td class="src"><a href="/usr/share/doc/ghc/html/libraries/transformers-0.3.0.0/Control-Monad-IO-Class.html#t:MonadIO">MonadIO</a> m => <a href="/usr/share/doc/ghc/html/libraries/transformers-0.3.0.0/Control-Monad-IO-Class.html#t:MonadIO">MonadIO</a> (<a href="Control-Monad-Logic.html#t:LogicT">LogicT</a> m)</td><td class="doc empty"> </td></tr><tr><td class="src"><a href="/usr/share/doc/ghc/html/libraries/base-4.5.0.0/Control-Monad.html#t:Monad">Monad</a> m => <a href="Control-Monad-Logic-Class.html#t:MonadLogic">MonadLogic</a> (<a href="Control-Monad-Logic.html#t:LogicT">LogicT</a> m)</td><td class="doc empty"> </td></tr></table></div></div></div><div class="top"><p class="src"><a name="v:runLogicT" class="def">runLogicT</a> :: <a href="Control-Monad-Logic.html#t:LogicT">LogicT</a> m a -> (a -> m r -> m r) -> m r -> m r<a href="src/Control-Monad-Logic.html#runLogicT" class="link">Source</a></p><div class="doc"><p>Runs a LogicT computation with the specified initial success and
failure continuations.
</p></div></div><div class="top"><p class="src"><a name="v:observeT" class="def">observeT</a> :: <a href="/usr/share/doc/ghc/html/libraries/base-4.5.0.0/Control-Monad.html#t:Monad">Monad</a> m => <a href="Control-Monad-Logic.html#t:LogicT">LogicT</a> m a -> m a<a href="src/Control-Monad-Logic.html#observeT" class="link">Source</a></p><div class="doc"><p>Extracts the first result from a LogicT computation,
failing otherwise.
</p></div></div><div class="top"><p class="src"><a name="v:observeManyT" class="def">observeManyT</a> :: <a href="/usr/share/doc/ghc/html/libraries/base-4.5.0.0/Control-Monad.html#t:Monad">Monad</a> m => <a href="/usr/share/doc/ghc/html/libraries/base-4.5.0.0/Data-Int.html#t:Int">Int</a> -> <a href="Control-Monad-Logic.html#t:LogicT">LogicT</a> m a -> m [a]<a href="src/Control-Monad-Logic.html#observeManyT" class="link">Source</a></p><div class="doc"><p>Extracts up to a given number of results from a LogicT computation.
</p></div></div><div class="top"><p class="src"><a name="v:observeAllT" class="def">observeAllT</a> :: <a href="/usr/share/doc/ghc/html/libraries/base-4.5.0.0/Control-Monad.html#t:Monad">Monad</a> m => <a href="Control-Monad-Logic.html#t:LogicT">LogicT</a> m a -> m [a]<a href="src/Control-Monad-Logic.html#observeAllT" class="link">Source</a></p><div class="doc"><p>Extracts all results from a LogicT computation.
</p></div></div><div class="top"><p class="src">module <a href="/usr/share/doc/ghc/html/libraries/base-4.5.0.0/Control-Monad.html">Control.Monad</a></p></div><div class="top"><p class="src">module <a href="/usr/share/doc/ghc/html/libraries/mtl-2.1.1/Control-Monad-Trans.html">Control.Monad.Trans</a></p></div></div></div><div id="footer"><p>Produced by <a href="http://www.haskell.org/haddock/">Haddock</a> version 2.10.0</p></div></body></html>
