<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html>
<head>
<!-- Generated by HsColour, http://www.cs.york.ac.uk/fp/darcs/hscolour/ -->
<title>Control/Monad/Trans/RWS/Strict.hs</title>
<link type='text/css' rel='stylesheet' href='hscolour.css' />
</head>
<body>
<pre><a name="line-1"></a><span class='hs-comment'>-----------------------------------------------------------------------------</span>
<a name="line-2"></a><span class='hs-comment'>-- |</span>
<a name="line-3"></a><span class='hs-comment'>-- Module : Control.Monad.Trans.RWS.Strict</span>
<a name="line-4"></a><span class='hs-comment'>-- Copyright : (c) Andy Gill 2001,</span>
<a name="line-5"></a><span class='hs-comment'>-- (c) Oregon Graduate Institute of Science and Technology, 2001</span>
<a name="line-6"></a><span class='hs-comment'>-- License : BSD-style (see the file LICENSE)</span>
<a name="line-7"></a><span class='hs-comment'>--</span>
<a name="line-8"></a><span class='hs-comment'>-- Maintainer : ross@soi.city.ac.uk</span>
<a name="line-9"></a><span class='hs-comment'>-- Stability : experimental</span>
<a name="line-10"></a><span class='hs-comment'>-- Portability : portable</span>
<a name="line-11"></a><span class='hs-comment'>--</span>
<a name="line-12"></a><span class='hs-comment'>-- A monad transformer that combines 'ReaderT', 'WriterT' and 'StateT'.</span>
<a name="line-13"></a><span class='hs-comment'>-- This version is strict; for a lazy version, see</span>
<a name="line-14"></a><span class='hs-comment'>-- "Control.Monad.Trans.RWS.Lazy", which has the same interface.</span>
<a name="line-15"></a><span class='hs-comment'>-----------------------------------------------------------------------------</span>
<a name="line-16"></a>
<a name="line-17"></a><span class='hs-keyword'>module</span> <span class='hs-conid'>Control</span><span class='hs-varop'>.</span><span class='hs-conid'>Monad</span><span class='hs-varop'>.</span><span class='hs-conid'>Trans</span><span class='hs-varop'>.</span><span class='hs-conid'>RWS</span><span class='hs-varop'>.</span><span class='hs-conid'>Strict</span> <span class='hs-layout'>(</span>
<a name="line-18"></a> <span class='hs-comment'>-- * The RWS monad</span>
<a name="line-19"></a> <span class='hs-conid'>RWS</span><span class='hs-layout'>,</span>
<a name="line-20"></a> <span class='hs-varid'>rws</span><span class='hs-layout'>,</span>
<a name="line-21"></a> <span class='hs-varid'>runRWS</span><span class='hs-layout'>,</span>
<a name="line-22"></a> <span class='hs-varid'>evalRWS</span><span class='hs-layout'>,</span>
<a name="line-23"></a> <span class='hs-varid'>execRWS</span><span class='hs-layout'>,</span>
<a name="line-24"></a> <span class='hs-varid'>mapRWS</span><span class='hs-layout'>,</span>
<a name="line-25"></a> <span class='hs-varid'>withRWS</span><span class='hs-layout'>,</span>
<a name="line-26"></a> <span class='hs-comment'>-- * The RWST monad transformer</span>
<a name="line-27"></a> <span class='hs-conid'>RWST</span><span class='hs-layout'>(</span><span class='hs-keyglyph'>..</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span>
<a name="line-28"></a> <span class='hs-varid'>evalRWST</span><span class='hs-layout'>,</span>
<a name="line-29"></a> <span class='hs-varid'>execRWST</span><span class='hs-layout'>,</span>
<a name="line-30"></a> <span class='hs-varid'>mapRWST</span><span class='hs-layout'>,</span>
<a name="line-31"></a> <span class='hs-varid'>withRWST</span><span class='hs-layout'>,</span>
<a name="line-32"></a> <span class='hs-comment'>-- * Reader operations</span>
<a name="line-33"></a> <span class='hs-varid'>ask</span><span class='hs-layout'>,</span>
<a name="line-34"></a> <span class='hs-varid'>local</span><span class='hs-layout'>,</span>
<a name="line-35"></a> <span class='hs-varid'>asks</span><span class='hs-layout'>,</span>
<a name="line-36"></a> <span class='hs-comment'>-- * Writer operations</span>
<a name="line-37"></a> <span class='hs-varid'>tell</span><span class='hs-layout'>,</span>
<a name="line-38"></a> <span class='hs-varid'>listen</span><span class='hs-layout'>,</span>
<a name="line-39"></a> <span class='hs-varid'>listens</span><span class='hs-layout'>,</span>
<a name="line-40"></a> <span class='hs-varid'>pass</span><span class='hs-layout'>,</span>
<a name="line-41"></a> <span class='hs-varid'>censor</span><span class='hs-layout'>,</span>
<a name="line-42"></a> <span class='hs-comment'>-- * State operations</span>
<a name="line-43"></a> <span class='hs-varid'>get</span><span class='hs-layout'>,</span>
<a name="line-44"></a> <span class='hs-varid'>put</span><span class='hs-layout'>,</span>
<a name="line-45"></a> <span class='hs-varid'>modify</span><span class='hs-layout'>,</span>
<a name="line-46"></a> <span class='hs-varid'>gets</span><span class='hs-layout'>,</span>
<a name="line-47"></a> <span class='hs-comment'>-- * Lifting other operations</span>
<a name="line-48"></a> <span class='hs-varid'>liftCallCC</span><span class='hs-layout'>,</span>
<a name="line-49"></a> <span class='hs-varid'>liftCallCC'</span><span class='hs-layout'>,</span>
<a name="line-50"></a> <span class='hs-varid'>liftCatch</span><span class='hs-layout'>,</span>
<a name="line-51"></a> <span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-52"></a>
<a name="line-53"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Control</span><span class='hs-varop'>.</span><span class='hs-conid'>Monad</span><span class='hs-varop'>.</span><span class='hs-conid'>IO</span><span class='hs-varop'>.</span><span class='hs-conid'>Class</span>
<a name="line-54"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Control</span><span class='hs-varop'>.</span><span class='hs-conid'>Monad</span><span class='hs-varop'>.</span><span class='hs-conid'>Trans</span><span class='hs-varop'>.</span><span class='hs-conid'>Class</span>
<a name="line-55"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Functor</span><span class='hs-varop'>.</span><span class='hs-conid'>Identity</span>
<a name="line-56"></a>
<a name="line-57"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Control</span><span class='hs-varop'>.</span><span class='hs-conid'>Applicative</span>
<a name="line-58"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Control</span><span class='hs-varop'>.</span><span class='hs-conid'>Monad</span>
<a name="line-59"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Control</span><span class='hs-varop'>.</span><span class='hs-conid'>Monad</span><span class='hs-varop'>.</span><span class='hs-conid'>Fix</span>
<a name="line-60"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Monoid</span>
<a name="line-61"></a>
<a name="line-62"></a><a name="RWS"></a><span class='hs-comment'>-- | A monad containing an environment of type @r@, output of type @w@</span>
<a name="line-63"></a><a name="RWS"></a><span class='hs-comment'>-- and an updatable state of type @s@.</span>
<a name="line-64"></a><a name="RWS"></a><span class='hs-keyword'>type</span> <span class='hs-conid'>RWS</span> <span class='hs-varid'>r</span> <span class='hs-varid'>w</span> <span class='hs-varid'>s</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>RWST</span> <span class='hs-varid'>r</span> <span class='hs-varid'>w</span> <span class='hs-varid'>s</span> <span class='hs-conid'>Identity</span>
<a name="line-65"></a>
<a name="line-66"></a><a name="rws"></a><span class='hs-comment'>-- | Construct an RWS computation from a function.</span>
<a name="line-67"></a><span class='hs-comment'>-- (The inverse of 'runRWS'.)</span>
<a name="line-68"></a><span class='hs-definition'>rws</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-varid'>r</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>s</span> <span class='hs-keyglyph'>-></span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-varid'>s</span><span class='hs-layout'>,</span> <span class='hs-varid'>w</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>RWS</span> <span class='hs-varid'>r</span> <span class='hs-varid'>w</span> <span class='hs-varid'>s</span> <span class='hs-varid'>a</span>
<a name="line-69"></a><span class='hs-definition'>rws</span> <span class='hs-varid'>f</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>RWST</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>\</span> <span class='hs-varid'>r</span> <span class='hs-varid'>s</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Identity</span> <span class='hs-layout'>(</span><span class='hs-varid'>f</span> <span class='hs-varid'>r</span> <span class='hs-varid'>s</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-70"></a>
<a name="line-71"></a><a name="runRWS"></a><span class='hs-comment'>-- | Unwrap an RWS computation as a function.</span>
<a name="line-72"></a><span class='hs-comment'>-- (The inverse of 'rws'.)</span>
<a name="line-73"></a><span class='hs-definition'>runRWS</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>RWS</span> <span class='hs-varid'>r</span> <span class='hs-varid'>w</span> <span class='hs-varid'>s</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>r</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>s</span> <span class='hs-keyglyph'>-></span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-varid'>s</span><span class='hs-layout'>,</span> <span class='hs-varid'>w</span><span class='hs-layout'>)</span>
<a name="line-74"></a><span class='hs-definition'>runRWS</span> <span class='hs-varid'>m</span> <span class='hs-varid'>r</span> <span class='hs-varid'>s</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>runIdentity</span> <span class='hs-layout'>(</span><span class='hs-varid'>runRWST</span> <span class='hs-varid'>m</span> <span class='hs-varid'>r</span> <span class='hs-varid'>s</span><span class='hs-layout'>)</span>
<a name="line-75"></a>
<a name="line-76"></a><a name="evalRWS"></a><span class='hs-definition'>evalRWS</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>RWS</span> <span class='hs-varid'>r</span> <span class='hs-varid'>w</span> <span class='hs-varid'>s</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>r</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>s</span> <span class='hs-keyglyph'>-></span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-varid'>w</span><span class='hs-layout'>)</span>
<a name="line-77"></a><span class='hs-definition'>evalRWS</span> <span class='hs-varid'>m</span> <span class='hs-varid'>r</span> <span class='hs-varid'>s</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>let</span>
<a name="line-78"></a> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-keyword'>_</span><span class='hs-layout'>,</span> <span class='hs-varid'>w</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>runRWS</span> <span class='hs-varid'>m</span> <span class='hs-varid'>r</span> <span class='hs-varid'>s</span>
<a name="line-79"></a> <span class='hs-keyword'>in</span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-varid'>w</span><span class='hs-layout'>)</span>
<a name="line-80"></a>
<a name="line-81"></a><a name="execRWS"></a><span class='hs-definition'>execRWS</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>RWS</span> <span class='hs-varid'>r</span> <span class='hs-varid'>w</span> <span class='hs-varid'>s</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>r</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>s</span> <span class='hs-keyglyph'>-></span> <span class='hs-layout'>(</span><span class='hs-varid'>s</span><span class='hs-layout'>,</span> <span class='hs-varid'>w</span><span class='hs-layout'>)</span>
<a name="line-82"></a><span class='hs-definition'>execRWS</span> <span class='hs-varid'>m</span> <span class='hs-varid'>r</span> <span class='hs-varid'>s</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>let</span>
<a name="line-83"></a> <span class='hs-layout'>(</span><span class='hs-keyword'>_</span><span class='hs-layout'>,</span> <span class='hs-varid'>s'</span><span class='hs-layout'>,</span> <span class='hs-varid'>w</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>runRWS</span> <span class='hs-varid'>m</span> <span class='hs-varid'>r</span> <span class='hs-varid'>s</span>
<a name="line-84"></a> <span class='hs-keyword'>in</span> <span class='hs-layout'>(</span><span class='hs-varid'>s'</span><span class='hs-layout'>,</span> <span class='hs-varid'>w</span><span class='hs-layout'>)</span>
<a name="line-85"></a>
<a name="line-86"></a><a name="mapRWS"></a><span class='hs-definition'>mapRWS</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-varid'>s</span><span class='hs-layout'>,</span> <span class='hs-varid'>w</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-layout'>(</span><span class='hs-varid'>b</span><span class='hs-layout'>,</span> <span class='hs-varid'>s</span><span class='hs-layout'>,</span> <span class='hs-varid'>w'</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>RWS</span> <span class='hs-varid'>r</span> <span class='hs-varid'>w</span> <span class='hs-varid'>s</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>RWS</span> <span class='hs-varid'>r</span> <span class='hs-varid'>w'</span> <span class='hs-varid'>s</span> <span class='hs-varid'>b</span>
<a name="line-87"></a><span class='hs-definition'>mapRWS</span> <span class='hs-varid'>f</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>mapRWST</span> <span class='hs-layout'>(</span><span class='hs-conid'>Identity</span> <span class='hs-varop'>.</span> <span class='hs-varid'>f</span> <span class='hs-varop'>.</span> <span class='hs-varid'>runIdentity</span><span class='hs-layout'>)</span>
<a name="line-88"></a>
<a name="line-89"></a><a name="withRWS"></a><span class='hs-definition'>withRWS</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-varid'>r'</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>s</span> <span class='hs-keyglyph'>-></span> <span class='hs-layout'>(</span><span class='hs-varid'>r</span><span class='hs-layout'>,</span> <span class='hs-varid'>s</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>RWS</span> <span class='hs-varid'>r</span> <span class='hs-varid'>w</span> <span class='hs-varid'>s</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>RWS</span> <span class='hs-varid'>r'</span> <span class='hs-varid'>w</span> <span class='hs-varid'>s</span> <span class='hs-varid'>a</span>
<a name="line-90"></a><span class='hs-definition'>withRWS</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>withRWST</span>
<a name="line-91"></a>
<a name="line-92"></a><a name="RWST"></a><span class='hs-comment'>-- ---------------------------------------------------------------------------</span>
<a name="line-93"></a><a name="RWST"></a><span class='hs-comment'>-- | A monad transformer adding reading an environment of type @r@,</span>
<a name="line-94"></a><a name="RWST"></a><span class='hs-comment'>-- collecting an output of type @w@ and updating a state of type @s@</span>
<a name="line-95"></a><a name="RWST"></a><span class='hs-comment'>-- to an inner monad @m@.</span>
<a name="line-96"></a><a name="RWST"></a><span class='hs-keyword'>newtype</span> <span class='hs-conid'>RWST</span> <span class='hs-varid'>r</span> <span class='hs-varid'>w</span> <span class='hs-varid'>s</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>RWST</span> <span class='hs-layout'>{</span> <span class='hs-varid'>runRWST</span> <span class='hs-keyglyph'>::</span> <span class='hs-varid'>r</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>s</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-varid'>s</span><span class='hs-layout'>,</span> <span class='hs-varid'>w</span><span class='hs-layout'>)</span> <span class='hs-layout'>}</span>
<a name="line-97"></a>
<a name="line-98"></a><a name="evalRWST"></a><span class='hs-definition'>evalRWST</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>RWST</span> <span class='hs-varid'>r</span> <span class='hs-varid'>w</span> <span class='hs-varid'>s</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>r</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>s</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-varid'>w</span><span class='hs-layout'>)</span>
<a name="line-99"></a><span class='hs-definition'>evalRWST</span> <span class='hs-varid'>m</span> <span class='hs-varid'>r</span> <span class='hs-varid'>s</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span>
<a name="line-100"></a> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-keyword'>_</span><span class='hs-layout'>,</span> <span class='hs-varid'>w</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>runRWST</span> <span class='hs-varid'>m</span> <span class='hs-varid'>r</span> <span class='hs-varid'>s</span>
<a name="line-101"></a> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-varid'>w</span><span class='hs-layout'>)</span>
<a name="line-102"></a>
<a name="line-103"></a><a name="execRWST"></a><span class='hs-definition'>execRWST</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>RWST</span> <span class='hs-varid'>r</span> <span class='hs-varid'>w</span> <span class='hs-varid'>s</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>r</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>s</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-layout'>(</span><span class='hs-varid'>s</span><span class='hs-layout'>,</span> <span class='hs-varid'>w</span><span class='hs-layout'>)</span>
<a name="line-104"></a><span class='hs-definition'>execRWST</span> <span class='hs-varid'>m</span> <span class='hs-varid'>r</span> <span class='hs-varid'>s</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span>
<a name="line-105"></a> <span class='hs-layout'>(</span><span class='hs-keyword'>_</span><span class='hs-layout'>,</span> <span class='hs-varid'>s'</span><span class='hs-layout'>,</span> <span class='hs-varid'>w</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>runRWST</span> <span class='hs-varid'>m</span> <span class='hs-varid'>r</span> <span class='hs-varid'>s</span>
<a name="line-106"></a> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>s'</span><span class='hs-layout'>,</span> <span class='hs-varid'>w</span><span class='hs-layout'>)</span>
<a name="line-107"></a>
<a name="line-108"></a><a name="mapRWST"></a><span class='hs-definition'>mapRWST</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-varid'>m</span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-varid'>s</span><span class='hs-layout'>,</span> <span class='hs-varid'>w</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>n</span> <span class='hs-layout'>(</span><span class='hs-varid'>b</span><span class='hs-layout'>,</span> <span class='hs-varid'>s</span><span class='hs-layout'>,</span> <span class='hs-varid'>w'</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>RWST</span> <span class='hs-varid'>r</span> <span class='hs-varid'>w</span> <span class='hs-varid'>s</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>RWST</span> <span class='hs-varid'>r</span> <span class='hs-varid'>w'</span> <span class='hs-varid'>s</span> <span class='hs-varid'>n</span> <span class='hs-varid'>b</span>
<a name="line-109"></a><span class='hs-definition'>mapRWST</span> <span class='hs-varid'>f</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>RWST</span> <span class='hs-varop'>$</span> <span class='hs-keyglyph'>\</span><span class='hs-varid'>r</span> <span class='hs-varid'>s</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>f</span> <span class='hs-layout'>(</span><span class='hs-varid'>runRWST</span> <span class='hs-varid'>m</span> <span class='hs-varid'>r</span> <span class='hs-varid'>s</span><span class='hs-layout'>)</span>
<a name="line-110"></a>
<a name="line-111"></a><a name="withRWST"></a><span class='hs-definition'>withRWST</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-varid'>r'</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>s</span> <span class='hs-keyglyph'>-></span> <span class='hs-layout'>(</span><span class='hs-varid'>r</span><span class='hs-layout'>,</span> <span class='hs-varid'>s</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>RWST</span> <span class='hs-varid'>r</span> <span class='hs-varid'>w</span> <span class='hs-varid'>s</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>RWST</span> <span class='hs-varid'>r'</span> <span class='hs-varid'>w</span> <span class='hs-varid'>s</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span>
<a name="line-112"></a><span class='hs-definition'>withRWST</span> <span class='hs-varid'>f</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>RWST</span> <span class='hs-varop'>$</span> <span class='hs-keyglyph'>\</span><span class='hs-varid'>r</span> <span class='hs-varid'>s</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>uncurry</span> <span class='hs-layout'>(</span><span class='hs-varid'>runRWST</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>f</span> <span class='hs-varid'>r</span> <span class='hs-varid'>s</span><span class='hs-layout'>)</span>
<a name="line-113"></a>
<a name="line-114"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>Functor</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>Functor</span> <span class='hs-layout'>(</span><span class='hs-conid'>RWST</span> <span class='hs-varid'>r</span> <span class='hs-varid'>w</span> <span class='hs-varid'>s</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-115"></a> <span class='hs-varid'>fmap</span> <span class='hs-varid'>f</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>RWST</span> <span class='hs-varop'>$</span> <span class='hs-keyglyph'>\</span><span class='hs-varid'>r</span> <span class='hs-varid'>s</span> <span class='hs-keyglyph'>-></span>
<a name="line-116"></a> <span class='hs-varid'>fmap</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>\</span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-varid'>s'</span><span class='hs-layout'>,</span> <span class='hs-varid'>w</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-layout'>(</span><span class='hs-varid'>f</span> <span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-varid'>s'</span><span class='hs-layout'>,</span> <span class='hs-varid'>w</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-varop'>$</span> <span class='hs-varid'>runRWST</span> <span class='hs-varid'>m</span> <span class='hs-varid'>r</span> <span class='hs-varid'>s</span>
<a name="line-117"></a>
<a name="line-118"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>Monoid</span> <span class='hs-varid'>w</span><span class='hs-layout'>,</span> <span class='hs-conid'>Functor</span> <span class='hs-varid'>m</span><span class='hs-layout'>,</span> <span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>Applicative</span> <span class='hs-layout'>(</span><span class='hs-conid'>RWST</span> <span class='hs-varid'>r</span> <span class='hs-varid'>w</span> <span class='hs-varid'>s</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-119"></a> <span class='hs-varid'>pure</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>return</span>
<a name="line-120"></a> <span class='hs-layout'>(</span><span class='hs-varop'><*></span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>ap</span>
<a name="line-121"></a>
<a name="line-122"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>Monoid</span> <span class='hs-varid'>w</span><span class='hs-layout'>,</span> <span class='hs-conid'>Functor</span> <span class='hs-varid'>m</span><span class='hs-layout'>,</span> <span class='hs-conid'>MonadPlus</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>Alternative</span> <span class='hs-layout'>(</span><span class='hs-conid'>RWST</span> <span class='hs-varid'>r</span> <span class='hs-varid'>w</span> <span class='hs-varid'>s</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-123"></a> <span class='hs-varid'>empty</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>mzero</span>
<a name="line-124"></a> <span class='hs-layout'>(</span><span class='hs-varop'><|></span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>mplus</span>
<a name="line-125"></a>
<a name="line-126"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>Monoid</span> <span class='hs-varid'>w</span><span class='hs-layout'>,</span> <span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>Monad</span> <span class='hs-layout'>(</span><span class='hs-conid'>RWST</span> <span class='hs-varid'>r</span> <span class='hs-varid'>w</span> <span class='hs-varid'>s</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-127"></a> <span class='hs-varid'>return</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>RWST</span> <span class='hs-varop'>$</span> <span class='hs-keyglyph'>\</span><span class='hs-keyword'>_</span> <span class='hs-varid'>s</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-varid'>s</span><span class='hs-layout'>,</span> <span class='hs-varid'>mempty</span><span class='hs-layout'>)</span>
<a name="line-128"></a> <span class='hs-varid'>m</span> <span class='hs-varop'>>>=</span> <span class='hs-varid'>k</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>RWST</span> <span class='hs-varop'>$</span> <span class='hs-keyglyph'>\</span><span class='hs-varid'>r</span> <span class='hs-varid'>s</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyword'>do</span>
<a name="line-129"></a> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-varid'>s'</span><span class='hs-layout'>,</span> <span class='hs-varid'>w</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>runRWST</span> <span class='hs-varid'>m</span> <span class='hs-varid'>r</span> <span class='hs-varid'>s</span>
<a name="line-130"></a> <span class='hs-layout'>(</span><span class='hs-varid'>b</span><span class='hs-layout'>,</span> <span class='hs-varid'>s''</span><span class='hs-layout'>,</span><span class='hs-varid'>w'</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>runRWST</span> <span class='hs-layout'>(</span><span class='hs-varid'>k</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span> <span class='hs-varid'>r</span> <span class='hs-varid'>s'</span>
<a name="line-131"></a> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>b</span><span class='hs-layout'>,</span> <span class='hs-varid'>s''</span><span class='hs-layout'>,</span> <span class='hs-varid'>w</span> <span class='hs-varop'>`mappend`</span> <span class='hs-varid'>w'</span><span class='hs-layout'>)</span>
<a name="line-132"></a> <span class='hs-varid'>fail</span> <span class='hs-varid'>msg</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>RWST</span> <span class='hs-varop'>$</span> <span class='hs-keyglyph'>\</span><span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>fail</span> <span class='hs-varid'>msg</span>
<a name="line-133"></a>
<a name="line-134"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>Monoid</span> <span class='hs-varid'>w</span><span class='hs-layout'>,</span> <span class='hs-conid'>MonadPlus</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>MonadPlus</span> <span class='hs-layout'>(</span><span class='hs-conid'>RWST</span> <span class='hs-varid'>r</span> <span class='hs-varid'>w</span> <span class='hs-varid'>s</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-135"></a> <span class='hs-varid'>mzero</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>RWST</span> <span class='hs-varop'>$</span> <span class='hs-keyglyph'>\</span><span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>mzero</span>
<a name="line-136"></a> <span class='hs-varid'>m</span> <span class='hs-varop'>`mplus`</span> <span class='hs-varid'>n</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>RWST</span> <span class='hs-varop'>$</span> <span class='hs-keyglyph'>\</span><span class='hs-varid'>r</span> <span class='hs-varid'>s</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>runRWST</span> <span class='hs-varid'>m</span> <span class='hs-varid'>r</span> <span class='hs-varid'>s</span> <span class='hs-varop'>`mplus`</span> <span class='hs-varid'>runRWST</span> <span class='hs-varid'>n</span> <span class='hs-varid'>r</span> <span class='hs-varid'>s</span>
<a name="line-137"></a>
<a name="line-138"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>Monoid</span> <span class='hs-varid'>w</span><span class='hs-layout'>,</span> <span class='hs-conid'>MonadFix</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>MonadFix</span> <span class='hs-layout'>(</span><span class='hs-conid'>RWST</span> <span class='hs-varid'>r</span> <span class='hs-varid'>w</span> <span class='hs-varid'>s</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-139"></a> <span class='hs-varid'>mfix</span> <span class='hs-varid'>f</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>RWST</span> <span class='hs-varop'>$</span> <span class='hs-keyglyph'>\</span><span class='hs-varid'>r</span> <span class='hs-varid'>s</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>mfix</span> <span class='hs-varop'>$</span> <span class='hs-keyglyph'>\</span> <span class='hs-keyglyph'>~</span><span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-keyword'>_</span><span class='hs-layout'>,</span> <span class='hs-keyword'>_</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>runRWST</span> <span class='hs-layout'>(</span><span class='hs-varid'>f</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span> <span class='hs-varid'>r</span> <span class='hs-varid'>s</span>
<a name="line-140"></a>
<a name="line-141"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>Monoid</span> <span class='hs-varid'>w</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>MonadTrans</span> <span class='hs-layout'>(</span><span class='hs-conid'>RWST</span> <span class='hs-varid'>r</span> <span class='hs-varid'>w</span> <span class='hs-varid'>s</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-142"></a> <span class='hs-varid'>lift</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>RWST</span> <span class='hs-varop'>$</span> <span class='hs-keyglyph'>\</span><span class='hs-keyword'>_</span> <span class='hs-varid'>s</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyword'>do</span>
<a name="line-143"></a> <span class='hs-varid'>a</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>m</span>
<a name="line-144"></a> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-varid'>s</span><span class='hs-layout'>,</span> <span class='hs-varid'>mempty</span><span class='hs-layout'>)</span>
<a name="line-145"></a>
<a name="line-146"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>Monoid</span> <span class='hs-varid'>w</span><span class='hs-layout'>,</span> <span class='hs-conid'>MonadIO</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>MonadIO</span> <span class='hs-layout'>(</span><span class='hs-conid'>RWST</span> <span class='hs-varid'>r</span> <span class='hs-varid'>w</span> <span class='hs-varid'>s</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-147"></a> <span class='hs-varid'>liftIO</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>lift</span> <span class='hs-varop'>.</span> <span class='hs-varid'>liftIO</span>
<a name="line-148"></a>
<a name="line-149"></a><span class='hs-comment'>-- ---------------------------------------------------------------------------</span>
<a name="line-150"></a><span class='hs-comment'>-- Reader operations</span>
<a name="line-151"></a>
<a name="line-152"></a><a name="ask"></a><span class='hs-comment'>-- | Fetch the value of the environment.</span>
<a name="line-153"></a><span class='hs-definition'>ask</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>Monoid</span> <span class='hs-varid'>w</span><span class='hs-layout'>,</span> <span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>RWST</span> <span class='hs-varid'>r</span> <span class='hs-varid'>w</span> <span class='hs-varid'>s</span> <span class='hs-varid'>m</span> <span class='hs-varid'>r</span>
<a name="line-154"></a><span class='hs-definition'>ask</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>RWST</span> <span class='hs-varop'>$</span> <span class='hs-keyglyph'>\</span><span class='hs-varid'>r</span> <span class='hs-varid'>s</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>r</span><span class='hs-layout'>,</span> <span class='hs-varid'>s</span><span class='hs-layout'>,</span> <span class='hs-varid'>mempty</span><span class='hs-layout'>)</span>
<a name="line-155"></a>
<a name="line-156"></a><a name="local"></a><span class='hs-comment'>-- | Execute a computation in a modified environment</span>
<a name="line-157"></a><span class='hs-definition'>local</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>Monoid</span> <span class='hs-varid'>w</span><span class='hs-layout'>,</span> <span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=></span> <span class='hs-layout'>(</span><span class='hs-varid'>r</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>r</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>RWST</span> <span class='hs-varid'>r</span> <span class='hs-varid'>w</span> <span class='hs-varid'>s</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>RWST</span> <span class='hs-varid'>r</span> <span class='hs-varid'>w</span> <span class='hs-varid'>s</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span>
<a name="line-158"></a><span class='hs-definition'>local</span> <span class='hs-varid'>f</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>RWST</span> <span class='hs-varop'>$</span> <span class='hs-keyglyph'>\</span><span class='hs-varid'>r</span> <span class='hs-varid'>s</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>runRWST</span> <span class='hs-varid'>m</span> <span class='hs-layout'>(</span><span class='hs-varid'>f</span> <span class='hs-varid'>r</span><span class='hs-layout'>)</span> <span class='hs-varid'>s</span>
<a name="line-159"></a>
<a name="line-160"></a><a name="asks"></a><span class='hs-comment'>-- | Retrieve a function of the current environment.</span>
<a name="line-161"></a><span class='hs-definition'>asks</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>Monoid</span> <span class='hs-varid'>w</span><span class='hs-layout'>,</span> <span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=></span> <span class='hs-layout'>(</span><span class='hs-varid'>r</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>RWST</span> <span class='hs-varid'>r</span> <span class='hs-varid'>w</span> <span class='hs-varid'>s</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span>
<a name="line-162"></a><span class='hs-definition'>asks</span> <span class='hs-varid'>f</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span>
<a name="line-163"></a> <span class='hs-varid'>r</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>ask</span>
<a name="line-164"></a> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>f</span> <span class='hs-varid'>r</span><span class='hs-layout'>)</span>
<a name="line-165"></a>
<a name="line-166"></a><span class='hs-comment'>-- ---------------------------------------------------------------------------</span>
<a name="line-167"></a><span class='hs-comment'>-- Writer operations</span>
<a name="line-168"></a>
<a name="line-169"></a><a name="tell"></a><span class='hs-comment'>-- | @'tell' w@ is an action that produces the output @w@.</span>
<a name="line-170"></a><span class='hs-definition'>tell</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>Monoid</span> <span class='hs-varid'>w</span><span class='hs-layout'>,</span> <span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=></span> <span class='hs-varid'>w</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>RWST</span> <span class='hs-varid'>r</span> <span class='hs-varid'>w</span> <span class='hs-varid'>s</span> <span class='hs-varid'>m</span> <span class='hs-conid'>()</span>
<a name="line-171"></a><span class='hs-definition'>tell</span> <span class='hs-varid'>w</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>RWST</span> <span class='hs-varop'>$</span> <span class='hs-keyglyph'>\</span><span class='hs-keyword'>_</span> <span class='hs-varid'>s</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-conid'>()</span><span class='hs-layout'>,</span><span class='hs-varid'>s</span><span class='hs-layout'>,</span><span class='hs-varid'>w</span><span class='hs-layout'>)</span>
<a name="line-172"></a>
<a name="line-173"></a><a name="listen"></a><span class='hs-comment'>-- | @'listen' m@ is an action that executes the action @m@ and adds its</span>
<a name="line-174"></a><span class='hs-comment'>-- output to the value of the computation.</span>
<a name="line-175"></a><span class='hs-definition'>listen</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>Monoid</span> <span class='hs-varid'>w</span><span class='hs-layout'>,</span> <span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>RWST</span> <span class='hs-varid'>r</span> <span class='hs-varid'>w</span> <span class='hs-varid'>s</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>RWST</span> <span class='hs-varid'>r</span> <span class='hs-varid'>w</span> <span class='hs-varid'>s</span> <span class='hs-varid'>m</span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-varid'>w</span><span class='hs-layout'>)</span>
<a name="line-176"></a><span class='hs-definition'>listen</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>RWST</span> <span class='hs-varop'>$</span> <span class='hs-keyglyph'>\</span><span class='hs-varid'>r</span> <span class='hs-varid'>s</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyword'>do</span>
<a name="line-177"></a> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-varid'>s'</span><span class='hs-layout'>,</span> <span class='hs-varid'>w</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>runRWST</span> <span class='hs-varid'>m</span> <span class='hs-varid'>r</span> <span class='hs-varid'>s</span>
<a name="line-178"></a> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-varid'>w</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span> <span class='hs-varid'>s'</span><span class='hs-layout'>,</span> <span class='hs-varid'>w</span><span class='hs-layout'>)</span>
<a name="line-179"></a>
<a name="line-180"></a><a name="listens"></a><span class='hs-comment'>-- | @'listens' f m@ is an action that executes the action @m@ and adds</span>
<a name="line-181"></a><span class='hs-comment'>-- the result of applying @f@ to the output to the value of the computation.</span>
<a name="line-182"></a><span class='hs-comment'>--</span>
<a name="line-183"></a><span class='hs-comment'>-- * @'listens' f m = 'liftM' (id *** f) ('listen' m)@</span>
<a name="line-184"></a><span class='hs-definition'>listens</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>Monoid</span> <span class='hs-varid'>w</span><span class='hs-layout'>,</span> <span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=></span> <span class='hs-layout'>(</span><span class='hs-varid'>w</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>b</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>RWST</span> <span class='hs-varid'>r</span> <span class='hs-varid'>w</span> <span class='hs-varid'>s</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>RWST</span> <span class='hs-varid'>r</span> <span class='hs-varid'>w</span> <span class='hs-varid'>s</span> <span class='hs-varid'>m</span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-varid'>b</span><span class='hs-layout'>)</span>
<a name="line-185"></a><span class='hs-definition'>listens</span> <span class='hs-varid'>f</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span>
<a name="line-186"></a> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-varid'>w</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>listen</span> <span class='hs-varid'>m</span>
<a name="line-187"></a> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-varid'>f</span> <span class='hs-varid'>w</span><span class='hs-layout'>)</span>
<a name="line-188"></a>
<a name="line-189"></a><a name="pass"></a><span class='hs-comment'>-- | @'pass' m@ is an action that executes the action @m@, which returns</span>
<a name="line-190"></a><span class='hs-comment'>-- a value and a function, and returns the value, applying the function</span>
<a name="line-191"></a><span class='hs-comment'>-- to the output.</span>
<a name="line-192"></a><span class='hs-definition'>pass</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>Monoid</span> <span class='hs-varid'>w</span><span class='hs-layout'>,</span> <span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>RWST</span> <span class='hs-varid'>r</span> <span class='hs-varid'>w</span> <span class='hs-varid'>s</span> <span class='hs-varid'>m</span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-varid'>w</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>w</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>RWST</span> <span class='hs-varid'>r</span> <span class='hs-varid'>w</span> <span class='hs-varid'>s</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span>
<a name="line-193"></a><span class='hs-definition'>pass</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>RWST</span> <span class='hs-varop'>$</span> <span class='hs-keyglyph'>\</span><span class='hs-varid'>r</span> <span class='hs-varid'>s</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyword'>do</span>
<a name="line-194"></a> <span class='hs-layout'>(</span><span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-varid'>f</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span> <span class='hs-varid'>s'</span><span class='hs-layout'>,</span> <span class='hs-varid'>w</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>runRWST</span> <span class='hs-varid'>m</span> <span class='hs-varid'>r</span> <span class='hs-varid'>s</span>
<a name="line-195"></a> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-varid'>s'</span><span class='hs-layout'>,</span> <span class='hs-varid'>f</span> <span class='hs-varid'>w</span><span class='hs-layout'>)</span>
<a name="line-196"></a>
<a name="line-197"></a><a name="censor"></a><span class='hs-comment'>-- | @'censor' f m@ is an action that executes the action @m@ and</span>
<a name="line-198"></a><span class='hs-comment'>-- applies the function @f@ to its output, leaving the return value</span>
<a name="line-199"></a><span class='hs-comment'>-- unchanged.</span>
<a name="line-200"></a><span class='hs-comment'>--</span>
<a name="line-201"></a><span class='hs-comment'>-- * @'censor' f m = 'pass' ('liftM' (\\x -> (x,f)) m)@</span>
<a name="line-202"></a><span class='hs-definition'>censor</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>Monoid</span> <span class='hs-varid'>w</span><span class='hs-layout'>,</span> <span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=></span> <span class='hs-layout'>(</span><span class='hs-varid'>w</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>w</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>RWST</span> <span class='hs-varid'>r</span> <span class='hs-varid'>w</span> <span class='hs-varid'>s</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>RWST</span> <span class='hs-varid'>r</span> <span class='hs-varid'>w</span> <span class='hs-varid'>s</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span>
<a name="line-203"></a><span class='hs-definition'>censor</span> <span class='hs-varid'>f</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>pass</span> <span class='hs-varop'>$</span> <span class='hs-keyword'>do</span>
<a name="line-204"></a> <span class='hs-varid'>a</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>m</span>
<a name="line-205"></a> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-varid'>f</span><span class='hs-layout'>)</span>
<a name="line-206"></a>
<a name="line-207"></a><span class='hs-comment'>-- ---------------------------------------------------------------------------</span>
<a name="line-208"></a><span class='hs-comment'>-- State operations</span>
<a name="line-209"></a>
<a name="line-210"></a><a name="get"></a><span class='hs-comment'>-- | Fetch the current value of the state within the monad.</span>
<a name="line-211"></a><span class='hs-definition'>get</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>Monoid</span> <span class='hs-varid'>w</span><span class='hs-layout'>,</span> <span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>RWST</span> <span class='hs-varid'>r</span> <span class='hs-varid'>w</span> <span class='hs-varid'>s</span> <span class='hs-varid'>m</span> <span class='hs-varid'>s</span>
<a name="line-212"></a><span class='hs-definition'>get</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>RWST</span> <span class='hs-varop'>$</span> <span class='hs-keyglyph'>\</span><span class='hs-keyword'>_</span> <span class='hs-varid'>s</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>s</span><span class='hs-layout'>,</span> <span class='hs-varid'>s</span><span class='hs-layout'>,</span> <span class='hs-varid'>mempty</span><span class='hs-layout'>)</span>
<a name="line-213"></a>
<a name="line-214"></a><a name="put"></a><span class='hs-comment'>-- | @'put' s@ sets the state within the monad to @s@.</span>
<a name="line-215"></a><span class='hs-definition'>put</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>Monoid</span> <span class='hs-varid'>w</span><span class='hs-layout'>,</span> <span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=></span> <span class='hs-varid'>s</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>RWST</span> <span class='hs-varid'>r</span> <span class='hs-varid'>w</span> <span class='hs-varid'>s</span> <span class='hs-varid'>m</span> <span class='hs-conid'>()</span>
<a name="line-216"></a><span class='hs-definition'>put</span> <span class='hs-varid'>s</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>RWST</span> <span class='hs-varop'>$</span> <span class='hs-keyglyph'>\</span><span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-conid'>()</span><span class='hs-layout'>,</span> <span class='hs-varid'>s</span><span class='hs-layout'>,</span> <span class='hs-varid'>mempty</span><span class='hs-layout'>)</span>
<a name="line-217"></a>
<a name="line-218"></a><a name="modify"></a><span class='hs-comment'>-- | @'modify' f@ is an action that updates the state to the result of</span>
<a name="line-219"></a><span class='hs-comment'>-- applying @f@ to the current state.</span>
<a name="line-220"></a><span class='hs-definition'>modify</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>Monoid</span> <span class='hs-varid'>w</span><span class='hs-layout'>,</span> <span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=></span> <span class='hs-layout'>(</span><span class='hs-varid'>s</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>s</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>RWST</span> <span class='hs-varid'>r</span> <span class='hs-varid'>w</span> <span class='hs-varid'>s</span> <span class='hs-varid'>m</span> <span class='hs-conid'>()</span>
<a name="line-221"></a><span class='hs-definition'>modify</span> <span class='hs-varid'>f</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span>
<a name="line-222"></a> <span class='hs-varid'>s</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>get</span>
<a name="line-223"></a> <span class='hs-varid'>put</span> <span class='hs-layout'>(</span><span class='hs-varid'>f</span> <span class='hs-varid'>s</span><span class='hs-layout'>)</span>
<a name="line-224"></a>
<a name="line-225"></a><a name="gets"></a><span class='hs-comment'>-- | Get a specific component of the state, using a projection function</span>
<a name="line-226"></a><span class='hs-comment'>-- supplied.</span>
<a name="line-227"></a><span class='hs-comment'>--</span>
<a name="line-228"></a><span class='hs-comment'>-- * @'gets' f = 'liftM' f 'get'@</span>
<a name="line-229"></a><span class='hs-definition'>gets</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>Monoid</span> <span class='hs-varid'>w</span><span class='hs-layout'>,</span> <span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=></span> <span class='hs-layout'>(</span><span class='hs-varid'>s</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>RWST</span> <span class='hs-varid'>r</span> <span class='hs-varid'>w</span> <span class='hs-varid'>s</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span>
<a name="line-230"></a><span class='hs-definition'>gets</span> <span class='hs-varid'>f</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span>
<a name="line-231"></a> <span class='hs-varid'>s</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>get</span>
<a name="line-232"></a> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>f</span> <span class='hs-varid'>s</span><span class='hs-layout'>)</span>
<a name="line-233"></a>
<a name="line-234"></a><a name="liftCallCC"></a><span class='hs-comment'>-- | Uniform lifting of a @callCC@ operation to the new monad.</span>
<a name="line-235"></a><span class='hs-comment'>-- This version rolls back to the original state on entering the</span>
<a name="line-236"></a><span class='hs-comment'>-- continuation.</span>
<a name="line-237"></a><span class='hs-definition'>liftCallCC</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>Monoid</span> <span class='hs-varid'>w</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=></span>
<a name="line-238"></a> <span class='hs-layout'>(</span><span class='hs-layout'>(</span><span class='hs-layout'>(</span><span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span><span class='hs-varid'>s</span><span class='hs-layout'>,</span><span class='hs-varid'>w</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-layout'>(</span><span class='hs-varid'>b</span><span class='hs-layout'>,</span><span class='hs-varid'>s</span><span class='hs-layout'>,</span><span class='hs-varid'>w</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span><span class='hs-varid'>s</span><span class='hs-layout'>,</span><span class='hs-varid'>w</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span><span class='hs-varid'>s</span><span class='hs-layout'>,</span><span class='hs-varid'>w</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span>
<a name="line-239"></a> <span class='hs-layout'>(</span><span class='hs-layout'>(</span><span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>RWST</span> <span class='hs-varid'>r</span> <span class='hs-varid'>w</span> <span class='hs-varid'>s</span> <span class='hs-varid'>m</span> <span class='hs-varid'>b</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>RWST</span> <span class='hs-varid'>r</span> <span class='hs-varid'>w</span> <span class='hs-varid'>s</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>RWST</span> <span class='hs-varid'>r</span> <span class='hs-varid'>w</span> <span class='hs-varid'>s</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span>
<a name="line-240"></a><span class='hs-definition'>liftCallCC</span> <span class='hs-varid'>callCC</span> <span class='hs-varid'>f</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>RWST</span> <span class='hs-varop'>$</span> <span class='hs-keyglyph'>\</span><span class='hs-varid'>r</span> <span class='hs-varid'>s</span> <span class='hs-keyglyph'>-></span>
<a name="line-241"></a> <span class='hs-varid'>callCC</span> <span class='hs-varop'>$</span> <span class='hs-keyglyph'>\</span><span class='hs-varid'>c</span> <span class='hs-keyglyph'>-></span>
<a name="line-242"></a> <span class='hs-varid'>runRWST</span> <span class='hs-layout'>(</span><span class='hs-varid'>f</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>\</span><span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>RWST</span> <span class='hs-varop'>$</span> <span class='hs-keyglyph'>\</span><span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>c</span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-varid'>s</span><span class='hs-layout'>,</span> <span class='hs-varid'>mempty</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-varid'>r</span> <span class='hs-varid'>s</span>
<a name="line-243"></a>
<a name="line-244"></a><a name="liftCallCC'"></a><span class='hs-comment'>-- | In-situ lifting of a @callCC@ operation to the new monad.</span>
<a name="line-245"></a><span class='hs-comment'>-- This version uses the current state on entering the continuation.</span>
<a name="line-246"></a><span class='hs-definition'>liftCallCC'</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>Monoid</span> <span class='hs-varid'>w</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=></span>
<a name="line-247"></a> <span class='hs-layout'>(</span><span class='hs-layout'>(</span><span class='hs-layout'>(</span><span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span><span class='hs-varid'>s</span><span class='hs-layout'>,</span><span class='hs-varid'>w</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-layout'>(</span><span class='hs-varid'>b</span><span class='hs-layout'>,</span><span class='hs-varid'>s</span><span class='hs-layout'>,</span><span class='hs-varid'>w</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span><span class='hs-varid'>s</span><span class='hs-layout'>,</span><span class='hs-varid'>w</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span><span class='hs-varid'>s</span><span class='hs-layout'>,</span><span class='hs-varid'>w</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span>
<a name="line-248"></a> <span class='hs-layout'>(</span><span class='hs-layout'>(</span><span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>RWST</span> <span class='hs-varid'>r</span> <span class='hs-varid'>w</span> <span class='hs-varid'>s</span> <span class='hs-varid'>m</span> <span class='hs-varid'>b</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>RWST</span> <span class='hs-varid'>r</span> <span class='hs-varid'>w</span> <span class='hs-varid'>s</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>RWST</span> <span class='hs-varid'>r</span> <span class='hs-varid'>w</span> <span class='hs-varid'>s</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span>
<a name="line-249"></a><span class='hs-definition'>liftCallCC'</span> <span class='hs-varid'>callCC</span> <span class='hs-varid'>f</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>RWST</span> <span class='hs-varop'>$</span> <span class='hs-keyglyph'>\</span><span class='hs-varid'>r</span> <span class='hs-varid'>s</span> <span class='hs-keyglyph'>-></span>
<a name="line-250"></a> <span class='hs-varid'>callCC</span> <span class='hs-varop'>$</span> <span class='hs-keyglyph'>\</span><span class='hs-varid'>c</span> <span class='hs-keyglyph'>-></span>
<a name="line-251"></a> <span class='hs-varid'>runRWST</span> <span class='hs-layout'>(</span><span class='hs-varid'>f</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>\</span><span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>RWST</span> <span class='hs-varop'>$</span> <span class='hs-keyglyph'>\</span><span class='hs-keyword'>_</span> <span class='hs-varid'>s'</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>c</span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-varid'>s'</span><span class='hs-layout'>,</span> <span class='hs-varid'>mempty</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-varid'>r</span> <span class='hs-varid'>s</span>
<a name="line-252"></a>
<a name="line-253"></a><a name="liftCatch"></a><span class='hs-comment'>-- | Lift a @catchError@ operation to the new monad.</span>
<a name="line-254"></a><span class='hs-definition'>liftCatch</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-varid'>m</span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span><span class='hs-varid'>s</span><span class='hs-layout'>,</span><span class='hs-varid'>w</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-layout'>(</span><span class='hs-varid'>e</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span><span class='hs-varid'>s</span><span class='hs-layout'>,</span><span class='hs-varid'>w</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span><span class='hs-varid'>s</span><span class='hs-layout'>,</span><span class='hs-varid'>w</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span>
<a name="line-255"></a> <span class='hs-conid'>RWST</span> <span class='hs-varid'>l</span> <span class='hs-varid'>w</span> <span class='hs-varid'>s</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-layout'>(</span><span class='hs-varid'>e</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>RWST</span> <span class='hs-varid'>l</span> <span class='hs-varid'>w</span> <span class='hs-varid'>s</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>RWST</span> <span class='hs-varid'>l</span> <span class='hs-varid'>w</span> <span class='hs-varid'>s</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span>
<a name="line-256"></a><span class='hs-definition'>liftCatch</span> <span class='hs-varid'>catchError</span> <span class='hs-varid'>m</span> <span class='hs-varid'>h</span> <span class='hs-keyglyph'>=</span>
<a name="line-257"></a> <span class='hs-conid'>RWST</span> <span class='hs-varop'>$</span> <span class='hs-keyglyph'>\</span><span class='hs-varid'>r</span> <span class='hs-varid'>s</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>runRWST</span> <span class='hs-varid'>m</span> <span class='hs-varid'>r</span> <span class='hs-varid'>s</span> <span class='hs-varop'>`catchError`</span> <span class='hs-keyglyph'>\</span><span class='hs-varid'>e</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>runRWST</span> <span class='hs-layout'>(</span><span class='hs-varid'>h</span> <span class='hs-varid'>e</span><span class='hs-layout'>)</span> <span class='hs-varid'>r</span> <span class='hs-varid'>s</span>
</pre></body>
</html>
