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<pre><a name="line-1"></a>
<a name="line-2"></a><span class='hs-comment'>-- | Utilities related to Monad and Applicative classes</span>
<a name="line-3"></a><span class='hs-comment'>-- Mostly for backwards compatability.</span>
<a name="line-4"></a>
<a name="line-5"></a><span class='hs-keyword'>module</span> <span class='hs-conid'>MonadUtils</span>
<a name="line-6"></a> <span class='hs-layout'>(</span> <span class='hs-conid'>Applicative</span><span class='hs-layout'>(</span><span class='hs-keyglyph'>..</span><span class='hs-layout'>)</span>
<a name="line-7"></a> <span class='hs-layout'>,</span> <span class='hs-layout'>(</span><span class='hs-varop'><$></span><span class='hs-layout'>)</span>
<a name="line-8"></a>
<a name="line-9"></a> <span class='hs-layout'>,</span> <span class='hs-conid'>MonadFix</span><span class='hs-layout'>(</span><span class='hs-keyglyph'>..</span><span class='hs-layout'>)</span>
<a name="line-10"></a> <span class='hs-layout'>,</span> <span class='hs-conid'>MonadIO</span><span class='hs-layout'>(</span><span class='hs-keyglyph'>..</span><span class='hs-layout'>)</span>
<a name="line-11"></a>
<a name="line-12"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>liftIO1</span><span class='hs-layout'>,</span> <span class='hs-varid'>liftIO2</span><span class='hs-layout'>,</span> <span class='hs-varid'>liftIO3</span><span class='hs-layout'>,</span> <span class='hs-varid'>liftIO4</span>
<a name="line-13"></a>
<a name="line-14"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>zipWith3M</span>
<a name="line-15"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>mapAndUnzipM</span><span class='hs-layout'>,</span> <span class='hs-varid'>mapAndUnzip3M</span><span class='hs-layout'>,</span> <span class='hs-varid'>mapAndUnzip4M</span>
<a name="line-16"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>mapAccumLM</span>
<a name="line-17"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>mapSndM</span>
<a name="line-18"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>concatMapM</span>
<a name="line-19"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>mapMaybeM</span>
<a name="line-20"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>anyM</span><span class='hs-layout'>,</span> <span class='hs-varid'>allM</span>
<a name="line-21"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>foldlM</span><span class='hs-layout'>,</span> <span class='hs-varid'>foldlM_</span><span class='hs-layout'>,</span> <span class='hs-varid'>foldrM</span>
<a name="line-22"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>maybeMapM</span>
<a name="line-23"></a> <span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-24"></a>
<a name="line-25"></a><span class='hs-comment'>----------------------------------------------------------------------------------------</span>
<a name="line-26"></a><span class='hs-comment'>-- Detection of available libraries</span>
<a name="line-27"></a><span class='hs-comment'>----------------------------------------------------------------------------------------</span>
<a name="line-28"></a>
<a name="line-29"></a><span class='hs-comment'>-- we don't depend on MTL for now</span>
<a name="line-30"></a><span class='hs-cpp'>#define HAVE_MTL 0</span>
<a name="line-31"></a>
<a name="line-32"></a><span class='hs-comment'>----------------------------------------------------------------------------------------</span>
<a name="line-33"></a><span class='hs-comment'>-- Imports</span>
<a name="line-34"></a><span class='hs-comment'>----------------------------------------------------------------------------------------</span>
<a name="line-35"></a>
<a name="line-36"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Maybes</span>
<a name="line-37"></a>
<a name="line-38"></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-39"></a><span class='hs-cpp'>#if HAVE_MTL</span>
<a name="line-40"></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>
<a name="line-41"></a><span class='hs-cpp'>#endif</span>
<a name="line-42"></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-43"></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-44"></a>
<a name="line-45"></a><span class='hs-comment'>----------------------------------------------------------------------------------------</span>
<a name="line-46"></a><span class='hs-comment'>-- MTL</span>
<a name="line-47"></a><span class='hs-comment'>----------------------------------------------------------------------------------------</span>
<a name="line-48"></a>
<a name="line-49"></a><span class='hs-cpp'>#if !HAVE_MTL</span>
<a name="line-50"></a>
<a name="line-51"></a><a name="MonadIO"></a><span class='hs-keyword'>class</span> <span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>MonadIO</span> <span class='hs-varid'>m</span> <span class='hs-keyword'>where</span>
<a name="line-52"></a> <span class='hs-varid'>liftIO</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>IO</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span>
<a name="line-53"></a>
<a name="line-54"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>MonadIO</span> <span class='hs-conid'>IO</span> <span class='hs-keyword'>where</span> <span class='hs-varid'>liftIO</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>id</span>
<a name="line-55"></a><span class='hs-cpp'>#endif</span>
<a name="line-56"></a>
<a name="line-57"></a><span class='hs-comment'>----------------------------------------------------------------------------------------</span>
<a name="line-58"></a><span class='hs-comment'>-- Lift combinators</span>
<a name="line-59"></a><span class='hs-comment'>-- These are used throughout the compiler</span>
<a name="line-60"></a><span class='hs-comment'>----------------------------------------------------------------------------------------</span>
<a name="line-61"></a>
<a name="line-62"></a><a name="liftIO1"></a><span class='hs-comment'>-- | Lift an 'IO' operation with 1 argument into another monad</span>
<a name="line-63"></a><span class='hs-definition'>liftIO1</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>MonadIO</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=></span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-varid'>b</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-varid'>m</span> <span class='hs-varid'>b</span>
<a name="line-64"></a><span class='hs-definition'>liftIO1</span> <span class='hs-keyglyph'>=</span> <span class='hs-layout'>(</span><span class='hs-varop'>.</span><span class='hs-layout'>)</span> <span class='hs-varid'>liftIO</span>
<a name="line-65"></a>
<a name="line-66"></a><a name="liftIO2"></a><span class='hs-comment'>-- | Lift an 'IO' operation with 2 arguments into another monad</span>
<a name="line-67"></a><span class='hs-definition'>liftIO2</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>MonadIO</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=></span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>b</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-varid'>c</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-varid'>b</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-varid'>c</span>
<a name="line-68"></a><span class='hs-definition'>liftIO2</span> <span class='hs-keyglyph'>=</span> <span class='hs-layout'>(</span><span class='hs-layout'>(</span><span class='hs-varop'>.</span><span class='hs-layout'>)</span><span class='hs-varop'>.</span><span class='hs-layout'>(</span><span class='hs-varop'>.</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-varid'>liftIO</span>
<a name="line-69"></a>
<a name="line-70"></a><a name="liftIO3"></a><span class='hs-comment'>-- | Lift an 'IO' operation with 3 arguments into another monad</span>
<a name="line-71"></a><span class='hs-definition'>liftIO3</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>MonadIO</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=></span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>b</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>c</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-varid'>d</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-varid'>b</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>c</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-varid'>d</span>
<a name="line-72"></a><span class='hs-definition'>liftIO3</span> <span class='hs-keyglyph'>=</span> <span class='hs-layout'>(</span><span class='hs-layout'>(</span><span class='hs-varop'>.</span><span class='hs-layout'>)</span><span class='hs-varop'>.</span><span class='hs-layout'>(</span><span class='hs-layout'>(</span><span class='hs-varop'>.</span><span class='hs-layout'>)</span><span class='hs-varop'>.</span><span class='hs-layout'>(</span><span class='hs-varop'>.</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-varid'>liftIO</span>
<a name="line-73"></a>
<a name="line-74"></a><a name="liftIO4"></a><span class='hs-comment'>-- | Lift an 'IO' operation with 4 arguments into another monad</span>
<a name="line-75"></a><span class='hs-definition'>liftIO4</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>MonadIO</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=></span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>b</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>c</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>d</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-varid'>e</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-varid'>b</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>c</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>d</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-varid'>e</span>
<a name="line-76"></a><span class='hs-definition'>liftIO4</span> <span class='hs-keyglyph'>=</span> <span class='hs-layout'>(</span><span class='hs-layout'>(</span><span class='hs-layout'>(</span><span class='hs-varop'>.</span><span class='hs-layout'>)</span><span class='hs-varop'>.</span><span class='hs-layout'>(</span><span class='hs-varop'>.</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span><span class='hs-varop'>.</span><span class='hs-layout'>(</span><span class='hs-layout'>(</span><span class='hs-varop'>.</span><span class='hs-layout'>)</span><span class='hs-varop'>.</span><span class='hs-layout'>(</span><span class='hs-varop'>.</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-varid'>liftIO</span>
<a name="line-77"></a>
<a name="line-78"></a><span class='hs-comment'>----------------------------------------------------------------------------------------</span>
<a name="line-79"></a><span class='hs-comment'>-- Common functions</span>
<a name="line-80"></a><span class='hs-comment'>-- These are used throughout the compiler</span>
<a name="line-81"></a><span class='hs-comment'>----------------------------------------------------------------------------------------</span>
<a name="line-82"></a>
<a name="line-83"></a><a name="zipWith3M"></a><span class='hs-definition'>zipWith3M</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=></span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>b</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>c</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-varid'>d</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>a</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>b</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>c</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>d</span><span class='hs-keyglyph'>]</span>
<a name="line-84"></a><span class='hs-definition'>zipWith3M</span> <span class='hs-keyword'>_</span> <span class='hs-conid'>[]</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-conid'>[]</span>
<a name="line-85"></a><span class='hs-definition'>zipWith3M</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span> <span class='hs-conid'>[]</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>return</span> <span class='hs-conid'>[]</span>
<a name="line-86"></a><span class='hs-definition'>zipWith3M</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span> <span class='hs-conid'>[]</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>return</span> <span class='hs-conid'>[]</span>
<a name="line-87"></a><span class='hs-definition'>zipWith3M</span> <span class='hs-varid'>f</span> <span class='hs-layout'>(</span><span class='hs-varid'>x</span><span class='hs-conop'>:</span><span class='hs-varid'>xs</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>y</span><span class='hs-conop'>:</span><span class='hs-varid'>ys</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>z</span><span class='hs-conop'>:</span><span class='hs-varid'>zs</span><span class='hs-layout'>)</span>
<a name="line-88"></a> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-layout'>{</span> <span class='hs-varid'>r</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>f</span> <span class='hs-varid'>x</span> <span class='hs-varid'>y</span> <span class='hs-varid'>z</span>
<a name="line-89"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>rs</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>zipWith3M</span> <span class='hs-varid'>f</span> <span class='hs-varid'>xs</span> <span class='hs-varid'>ys</span> <span class='hs-varid'>zs</span>
<a name="line-90"></a> <span class='hs-layout'>;</span> <span class='hs-varid'>return</span> <span class='hs-varop'>$</span> <span class='hs-varid'>r</span><span class='hs-conop'>:</span><span class='hs-varid'>rs</span>
<a name="line-91"></a> <span class='hs-layout'>}</span>
<a name="line-92"></a>
<a name="line-93"></a><a name="mapAndUnzip3M"></a><span class='hs-comment'>-- | mapAndUnzipM for triples</span>
<a name="line-94"></a><span class='hs-definition'>mapAndUnzip3M</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=></span> <span class='hs-layout'>(</span><span class='hs-varid'>a</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'>c</span><span class='hs-layout'>,</span><span class='hs-varid'>d</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>a</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>[</span><span class='hs-varid'>b</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>,</span><span class='hs-keyglyph'>[</span><span class='hs-varid'>c</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>,</span><span class='hs-keyglyph'>[</span><span class='hs-varid'>d</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>)</span>
<a name="line-95"></a><span class='hs-definition'>mapAndUnzip3M</span> <span class='hs-keyword'>_</span> <span class='hs-conid'>[]</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-conid'>[]</span><span class='hs-layout'>,</span><span class='hs-conid'>[]</span><span class='hs-layout'>)</span>
<a name="line-96"></a><span class='hs-definition'>mapAndUnzip3M</span> <span class='hs-varid'>f</span> <span class='hs-layout'>(</span><span class='hs-varid'>x</span><span class='hs-conop'>:</span><span class='hs-varid'>xs</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span>
<a name="line-97"></a> <span class='hs-layout'>(</span><span class='hs-varid'>r1</span><span class='hs-layout'>,</span> <span class='hs-varid'>r2</span><span class='hs-layout'>,</span> <span class='hs-varid'>r3</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>f</span> <span class='hs-varid'>x</span>
<a name="line-98"></a> <span class='hs-layout'>(</span><span class='hs-varid'>rs1</span><span class='hs-layout'>,</span> <span class='hs-varid'>rs2</span><span class='hs-layout'>,</span> <span class='hs-varid'>rs3</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>mapAndUnzip3M</span> <span class='hs-varid'>f</span> <span class='hs-varid'>xs</span>
<a name="line-99"></a> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>r1</span><span class='hs-conop'>:</span><span class='hs-varid'>rs1</span><span class='hs-layout'>,</span> <span class='hs-varid'>r2</span><span class='hs-conop'>:</span><span class='hs-varid'>rs2</span><span class='hs-layout'>,</span> <span class='hs-varid'>r3</span><span class='hs-conop'>:</span><span class='hs-varid'>rs3</span><span class='hs-layout'>)</span>
<a name="line-100"></a>
<a name="line-101"></a><a name="mapAndUnzip4M"></a><span class='hs-definition'>mapAndUnzip4M</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=></span> <span class='hs-layout'>(</span><span class='hs-varid'>a</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'>c</span><span class='hs-layout'>,</span><span class='hs-varid'>d</span><span class='hs-layout'>,</span><span class='hs-varid'>e</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>a</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>[</span><span class='hs-varid'>b</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>,</span><span class='hs-keyglyph'>[</span><span class='hs-varid'>c</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>,</span><span class='hs-keyglyph'>[</span><span class='hs-varid'>d</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>,</span><span class='hs-keyglyph'>[</span><span class='hs-varid'>e</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>)</span>
<a name="line-102"></a><span class='hs-definition'>mapAndUnzip4M</span> <span class='hs-keyword'>_</span> <span class='hs-conid'>[]</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-conid'>[]</span><span class='hs-layout'>,</span><span class='hs-conid'>[]</span><span class='hs-layout'>,</span><span class='hs-conid'>[]</span><span class='hs-layout'>)</span>
<a name="line-103"></a><span class='hs-definition'>mapAndUnzip4M</span> <span class='hs-varid'>f</span> <span class='hs-layout'>(</span><span class='hs-varid'>x</span><span class='hs-conop'>:</span><span class='hs-varid'>xs</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span>
<a name="line-104"></a> <span class='hs-layout'>(</span><span class='hs-varid'>r1</span><span class='hs-layout'>,</span> <span class='hs-varid'>r2</span><span class='hs-layout'>,</span> <span class='hs-varid'>r3</span><span class='hs-layout'>,</span> <span class='hs-varid'>r4</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>f</span> <span class='hs-varid'>x</span>
<a name="line-105"></a> <span class='hs-layout'>(</span><span class='hs-varid'>rs1</span><span class='hs-layout'>,</span> <span class='hs-varid'>rs2</span><span class='hs-layout'>,</span> <span class='hs-varid'>rs3</span><span class='hs-layout'>,</span> <span class='hs-varid'>rs4</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>mapAndUnzip4M</span> <span class='hs-varid'>f</span> <span class='hs-varid'>xs</span>
<a name="line-106"></a> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>r1</span><span class='hs-conop'>:</span><span class='hs-varid'>rs1</span><span class='hs-layout'>,</span> <span class='hs-varid'>r2</span><span class='hs-conop'>:</span><span class='hs-varid'>rs2</span><span class='hs-layout'>,</span> <span class='hs-varid'>r3</span><span class='hs-conop'>:</span><span class='hs-varid'>rs3</span><span class='hs-layout'>,</span> <span class='hs-varid'>r4</span><span class='hs-conop'>:</span><span class='hs-varid'>rs4</span><span class='hs-layout'>)</span>
<a name="line-107"></a>
<a name="line-108"></a><a name="mapAccumLM"></a><span class='hs-comment'>-- | Monadic version of mapAccumL</span>
<a name="line-109"></a><span class='hs-definition'>mapAccumLM</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span>
<a name="line-110"></a> <span class='hs-keyglyph'>=></span> <span class='hs-layout'>(</span><span class='hs-varid'>acc</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>x</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-layout'>(</span><span class='hs-varid'>acc</span><span class='hs-layout'>,</span> <span class='hs-varid'>y</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-comment'>-- ^ combining funcction</span>
<a name="line-111"></a> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>acc</span> <span class='hs-comment'>-- ^ initial state</span>
<a name="line-112"></a> <span class='hs-keyglyph'>-></span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>x</span><span class='hs-keyglyph'>]</span> <span class='hs-comment'>-- ^ inputs</span>
<a name="line-113"></a> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-layout'>(</span><span class='hs-varid'>acc</span><span class='hs-layout'>,</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>y</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>)</span> <span class='hs-comment'>-- ^ final state, outputs</span>
<a name="line-114"></a><span class='hs-definition'>mapAccumLM</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>s</span> <span class='hs-conid'>[]</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-conid'>[]</span><span class='hs-layout'>)</span>
<a name="line-115"></a><span class='hs-definition'>mapAccumLM</span> <span class='hs-varid'>f</span> <span class='hs-varid'>s</span> <span class='hs-layout'>(</span><span class='hs-varid'>x</span><span class='hs-conop'>:</span><span class='hs-varid'>xs</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span>
<a name="line-116"></a> <span class='hs-layout'>(</span><span class='hs-varid'>s1</span><span class='hs-layout'>,</span> <span class='hs-varid'>x'</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>f</span> <span class='hs-varid'>s</span> <span class='hs-varid'>x</span>
<a name="line-117"></a> <span class='hs-layout'>(</span><span class='hs-varid'>s2</span><span class='hs-layout'>,</span> <span class='hs-varid'>xs'</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>mapAccumLM</span> <span class='hs-varid'>f</span> <span class='hs-varid'>s1</span> <span class='hs-varid'>xs</span>
<a name="line-118"></a> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>s2</span><span class='hs-layout'>,</span> <span class='hs-varid'>x'</span> <span class='hs-conop'>:</span> <span class='hs-varid'>xs'</span><span class='hs-layout'>)</span>
<a name="line-119"></a>
<a name="line-120"></a><a name="mapSndM"></a><span class='hs-comment'>-- | Monadic version of mapSnd</span>
<a name="line-121"></a><span class='hs-definition'>mapSndM</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=></span> <span class='hs-layout'>(</span><span class='hs-varid'>b</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-varid'>c</span><span class='hs-layout'>)</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-varid'>b</span><span class='hs-layout'>)</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</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'>c</span><span class='hs-layout'>)</span><span class='hs-keyglyph'>]</span>
<a name="line-122"></a><span class='hs-definition'>mapSndM</span> <span class='hs-keyword'>_</span> <span class='hs-conid'>[]</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>return</span> <span class='hs-conid'>[]</span>
<a name="line-123"></a><span class='hs-definition'>mapSndM</span> <span class='hs-varid'>f</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'>b</span><span class='hs-layout'>)</span><span class='hs-conop'>:</span><span class='hs-varid'>xs</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-layout'>{</span> <span class='hs-varid'>c</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>f</span> <span class='hs-varid'>b</span><span class='hs-layout'>;</span> <span class='hs-varid'>rs</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>mapSndM</span> <span class='hs-varid'>f</span> <span class='hs-varid'>xs</span><span class='hs-layout'>;</span> <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'>c</span><span class='hs-layout'>)</span><span class='hs-conop'>:</span><span class='hs-varid'>rs</span><span class='hs-layout'>)</span> <span class='hs-layout'>}</span>
<a name="line-124"></a>
<a name="line-125"></a><a name="concatMapM"></a><span class='hs-comment'>-- | Monadic version of concatMap</span>
<a name="line-126"></a><span class='hs-definition'>concatMapM</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=></span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>b</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>a</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>b</span><span class='hs-keyglyph'>]</span>
<a name="line-127"></a><span class='hs-definition'>concatMapM</span> <span class='hs-varid'>f</span> <span class='hs-varid'>xs</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>liftM</span> <span class='hs-varid'>concat</span> <span class='hs-layout'>(</span><span class='hs-varid'>mapM</span> <span class='hs-varid'>f</span> <span class='hs-varid'>xs</span><span class='hs-layout'>)</span>
<a name="line-128"></a>
<a name="line-129"></a><a name="mapMaybeM"></a><span class='hs-comment'>-- | Monadic version of mapMaybe</span>
<a name="line-130"></a><span class='hs-definition'>mapMaybeM</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-layout'>(</span><span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-layout'>(</span><span class='hs-conid'>Maybe</span> <span class='hs-varid'>b</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>a</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>b</span><span class='hs-keyglyph'>]</span>
<a name="line-131"></a><span class='hs-definition'>mapMaybeM</span> <span class='hs-varid'>f</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>liftM</span> <span class='hs-varid'>catMaybes</span> <span class='hs-varop'>.</span> <span class='hs-varid'>mapM</span> <span class='hs-varid'>f</span>
<a name="line-132"></a>
<a name="line-133"></a><a name="anyM"></a><span class='hs-comment'>-- | Monadic version of 'any', aborts the computation at the first @True@ value</span>
<a name="line-134"></a><span class='hs-definition'>anyM</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=></span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-conid'>Bool</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>a</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-conid'>Bool</span>
<a name="line-135"></a><span class='hs-definition'>anyM</span> <span class='hs-keyword'>_</span> <span class='hs-conid'>[]</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>return</span> <span class='hs-conid'>False</span>
<a name="line-136"></a><span class='hs-definition'>anyM</span> <span class='hs-varid'>f</span> <span class='hs-layout'>(</span><span class='hs-varid'>x</span><span class='hs-conop'>:</span><span class='hs-varid'>xs</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-varid'>b</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>f</span> <span class='hs-varid'>x</span>
<a name="line-137"></a> <span class='hs-keyword'>if</span> <span class='hs-varid'>b</span> <span class='hs-keyword'>then</span> <span class='hs-varid'>return</span> <span class='hs-conid'>True</span>
<a name="line-138"></a> <span class='hs-keyword'>else</span> <span class='hs-varid'>anyM</span> <span class='hs-varid'>f</span> <span class='hs-varid'>xs</span>
<a name="line-139"></a>
<a name="line-140"></a><a name="allM"></a><span class='hs-comment'>-- | Monad version of 'all', aborts the computation at the first @False@ value</span>
<a name="line-141"></a><span class='hs-definition'>allM</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=></span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-conid'>Bool</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>a</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-conid'>Bool</span>
<a name="line-142"></a><span class='hs-definition'>allM</span> <span class='hs-keyword'>_</span> <span class='hs-conid'>[]</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>return</span> <span class='hs-conid'>True</span>
<a name="line-143"></a><span class='hs-definition'>allM</span> <span class='hs-varid'>f</span> <span class='hs-layout'>(</span><span class='hs-varid'>b</span><span class='hs-conop'>:</span><span class='hs-varid'>bs</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'>b</span><span class='hs-layout'>)</span> <span class='hs-varop'>>>=</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>\</span><span class='hs-varid'>bv</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyword'>if</span> <span class='hs-varid'>bv</span> <span class='hs-keyword'>then</span> <span class='hs-varid'>allM</span> <span class='hs-varid'>f</span> <span class='hs-varid'>bs</span> <span class='hs-keyword'>else</span> <span class='hs-varid'>return</span> <span class='hs-conid'>False</span><span class='hs-layout'>)</span>
<a name="line-144"></a>
<a name="line-145"></a><a name="foldlM"></a><span class='hs-comment'>-- | Monadic version of foldl</span>
<a name="line-146"></a><span class='hs-definition'>foldlM</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-layout'>(</span><span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>b</span> <span class='hs-keyglyph'>-></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-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>b</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span>
<a name="line-147"></a><span class='hs-definition'>foldlM</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>foldM</span>
<a name="line-148"></a>
<a name="line-149"></a><a name="foldlM_"></a><span class='hs-comment'>-- | Monadic version of foldl that discards its result</span>
<a name="line-150"></a><span class='hs-definition'>foldlM_</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-layout'>(</span><span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>b</span> <span class='hs-keyglyph'>-></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-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>b</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-conid'>()</span>
<a name="line-151"></a><span class='hs-definition'>foldlM_</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>foldM_</span>
<a name="line-152"></a>
<a name="line-153"></a><a name="foldrM"></a><span class='hs-comment'>-- | Monadic version of foldr</span>
<a name="line-154"></a><span class='hs-definition'>foldrM</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-layout'>(</span><span class='hs-varid'>b</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></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-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>b</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span>
<a name="line-155"></a><span class='hs-definition'>foldrM</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>z</span> <span class='hs-conid'>[]</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>return</span> <span class='hs-varid'>z</span>
<a name="line-156"></a><span class='hs-definition'>foldrM</span> <span class='hs-varid'>k</span> <span class='hs-varid'>z</span> <span class='hs-layout'>(</span><span class='hs-varid'>x</span><span class='hs-conop'>:</span><span class='hs-varid'>xs</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-layout'>{</span> <span class='hs-varid'>r</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>foldrM</span> <span class='hs-varid'>k</span> <span class='hs-varid'>z</span> <span class='hs-varid'>xs</span><span class='hs-layout'>;</span> <span class='hs-varid'>k</span> <span class='hs-varid'>x</span> <span class='hs-varid'>r</span> <span class='hs-layout'>}</span>
<a name="line-157"></a>
<a name="line-158"></a><a name="maybeMapM"></a><span class='hs-comment'>-- | Monadic version of fmap specialised for Maybe</span>
<a name="line-159"></a><span class='hs-definition'>maybeMapM</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=></span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></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-layout'>(</span><span class='hs-conid'>Maybe</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-layout'>(</span><span class='hs-conid'>Maybe</span> <span class='hs-varid'>b</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-160"></a><span class='hs-definition'>maybeMapM</span> <span class='hs-keyword'>_</span> <span class='hs-conid'>Nothing</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>return</span> <span class='hs-conid'>Nothing</span>
<a name="line-161"></a><span class='hs-definition'>maybeMapM</span> <span class='hs-varid'>m</span> <span class='hs-layout'>(</span><span class='hs-conid'>Just</span> <span class='hs-varid'>x</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>liftM</span> <span class='hs-conid'>Just</span> <span class='hs-varop'>$</span> <span class='hs-varid'>m</span> <span class='hs-varid'>x</span>
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