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<pre><a name="line-1"></a><span class='hs-comment'>-- | Defines the types for a conduit, which is a transformer of data. A conduit</span>
<a name="line-2"></a><span class='hs-comment'>-- is almost always connected either left (to a source) or right (to a sink).</span>
<a name="line-3"></a><span class='hs-keyword'>module</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Conduit</span><span class='hs-varop'>.</span><span class='hs-conid'>Types</span><span class='hs-varop'>.</span><span class='hs-conid'>Conduit</span>
<a name="line-4"></a> <span class='hs-layout'>(</span> <span class='hs-conid'>ConduitResult</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>..</span><span class='hs-layout'>)</span>
<a name="line-5"></a> <span class='hs-layout'>,</span> <span class='hs-conid'>Conduit</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>..</span><span class='hs-layout'>)</span>
<a name="line-6"></a> <span class='hs-layout'>,</span> <span class='hs-conid'>ConduitPush</span>
<a name="line-7"></a> <span class='hs-layout'>,</span> <span class='hs-conid'>ConduitClose</span>
<a name="line-8"></a> <span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-9"></a>
<a name="line-10"></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'>Resource</span> <span class='hs-layout'>(</span><span class='hs-conid'>ResourceT</span><span class='hs-layout'>)</span>
<a name="line-11"></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-layout'>(</span><span class='hs-varid'>liftM</span><span class='hs-layout'>)</span>
<a name="line-12"></a>
<a name="line-13"></a><a name="ConduitPush"></a><span class='hs-comment'>-- | The value of the @conduitPush@ record.</span>
<a name="line-14"></a><a name="ConduitPush"></a><span class='hs-keyword'>type</span> <span class='hs-conid'>ConduitPush</span> <span class='hs-varid'>input</span> <span class='hs-varid'>m</span> <span class='hs-varid'>output</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>input</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>ResourceT</span> <span class='hs-varid'>m</span> <span class='hs-layout'>(</span><span class='hs-conid'>ConduitResult</span> <span class='hs-varid'>input</span> <span class='hs-varid'>m</span> <span class='hs-varid'>output</span><span class='hs-layout'>)</span>
<a name="line-15"></a>
<a name="line-16"></a><a name="ConduitClose"></a><span class='hs-comment'>-- | The value of the @conduitClose@ record.</span>
<a name="line-17"></a><a name="ConduitClose"></a><span class='hs-keyword'>type</span> <span class='hs-conid'>ConduitClose</span> <span class='hs-varid'>m</span> <span class='hs-varid'>output</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>ResourceT</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>output</span><span class='hs-keyglyph'>]</span>
<a name="line-18"></a>
<a name="line-19"></a><a name="ConduitResult"></a><span class='hs-comment'>-- | When data is pushed to a @Conduit@, it may either indicate that it is</span>
<a name="line-20"></a><a name="ConduitResult"></a><span class='hs-comment'>-- still producing output and provide some, or indicate that it is finished</span>
<a name="line-21"></a><a name="ConduitResult"></a><span class='hs-comment'>-- producing output, in which case it returns optional leftover input and some</span>
<a name="line-22"></a><a name="ConduitResult"></a><span class='hs-comment'>-- final output.</span>
<a name="line-23"></a><a name="ConduitResult"></a><span class='hs-comment'>--</span>
<a name="line-24"></a><a name="ConduitResult"></a><span class='hs-comment'>-- The @Producing@ constructor provides a new @Conduit@ to be used in place of</span>
<a name="line-25"></a><a name="ConduitResult"></a><span class='hs-comment'>-- the previous one.</span>
<a name="line-26"></a><a name="ConduitResult"></a><span class='hs-comment'>--</span>
<a name="line-27"></a><a name="ConduitResult"></a><span class='hs-comment'>-- Since 0.2.0</span>
<a name="line-28"></a><a name="ConduitResult"></a><span class='hs-keyword'>data</span> <span class='hs-conid'>ConduitResult</span> <span class='hs-varid'>input</span> <span class='hs-varid'>m</span> <span class='hs-varid'>output</span> <span class='hs-keyglyph'>=</span>
<a name="line-29"></a> <span class='hs-conid'>Producing</span> <span class='hs-layout'>(</span><span class='hs-conid'>Conduit</span> <span class='hs-varid'>input</span> <span class='hs-varid'>m</span> <span class='hs-varid'>output</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>output</span><span class='hs-keyglyph'>]</span>
<a name="line-30"></a> <span class='hs-keyglyph'>|</span> <span class='hs-conid'>Finished</span> <span class='hs-layout'>(</span><span class='hs-conid'>Maybe</span> <span class='hs-varid'>input</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>output</span><span class='hs-keyglyph'>]</span>
<a name="line-31"></a>
<a name="line-32"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>Functor</span> <span class='hs-layout'>(</span><span class='hs-conid'>ConduitResult</span> <span class='hs-varid'>input</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-33"></a> <span class='hs-varid'>fmap</span> <span class='hs-varid'>f</span> <span class='hs-layout'>(</span><span class='hs-conid'>Producing</span> <span class='hs-varid'>c</span> <span class='hs-varid'>o</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Producing</span> <span class='hs-layout'>(</span><span class='hs-varid'>fmap</span> <span class='hs-varid'>f</span> <span class='hs-varid'>c</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>fmap</span> <span class='hs-varid'>f</span> <span class='hs-varid'>o</span><span class='hs-layout'>)</span>
<a name="line-34"></a> <span class='hs-varid'>fmap</span> <span class='hs-varid'>f</span> <span class='hs-layout'>(</span><span class='hs-conid'>Finished</span> <span class='hs-varid'>i</span> <span class='hs-varid'>o</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Finished</span> <span class='hs-varid'>i</span> <span class='hs-layout'>(</span><span class='hs-varid'>fmap</span> <span class='hs-varid'>f</span> <span class='hs-varid'>o</span><span class='hs-layout'>)</span>
<a name="line-35"></a>
<a name="line-36"></a><a name="Conduit"></a><span class='hs-comment'>-- | A conduit has two operations: it can receive new input (a push), and can</span>
<a name="line-37"></a><a name="Conduit"></a><span class='hs-comment'>-- be closed.</span>
<a name="line-38"></a><a name="Conduit"></a><span class='hs-comment'>--</span>
<a name="line-39"></a><a name="Conduit"></a><span class='hs-comment'>-- Since 0.2.0</span>
<a name="line-40"></a><a name="Conduit"></a><span class='hs-keyword'>data</span> <span class='hs-conid'>Conduit</span> <span class='hs-varid'>input</span> <span class='hs-varid'>m</span> <span class='hs-varid'>output</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Conduit</span>
<a name="line-41"></a> <span class='hs-layout'>{</span> <span class='hs-varid'>conduitPush</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>ConduitPush</span> <span class='hs-varid'>input</span> <span class='hs-varid'>m</span> <span class='hs-varid'>output</span>
<a name="line-42"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>conduitClose</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>ConduitClose</span> <span class='hs-varid'>m</span> <span class='hs-varid'>output</span>
<a name="line-43"></a> <span class='hs-layout'>}</span>
<a name="line-44"></a>
<a name="line-45"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>Functor</span> <span class='hs-layout'>(</span><span class='hs-conid'>Conduit</span> <span class='hs-varid'>input</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-46"></a> <span class='hs-varid'>fmap</span> <span class='hs-varid'>f</span> <span class='hs-varid'>c</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>c</span>
<a name="line-47"></a> <span class='hs-layout'>{</span> <span class='hs-varid'>conduitPush</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>liftM</span> <span class='hs-layout'>(</span><span class='hs-varid'>fmap</span> <span class='hs-varid'>f</span><span class='hs-layout'>)</span> <span class='hs-varop'>.</span> <span class='hs-varid'>conduitPush</span> <span class='hs-varid'>c</span>
<a name="line-48"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>conduitClose</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>liftM</span> <span class='hs-layout'>(</span><span class='hs-varid'>fmap</span> <span class='hs-varid'>f</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>conduitClose</span> <span class='hs-varid'>c</span><span class='hs-layout'>)</span>
<a name="line-49"></a> <span class='hs-layout'>}</span>
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