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<pre><a name="line-1"></a><span class='comment'>-- ------------------------------------------------------------</span>
<a name="line-2"></a>
<a name="line-3"></a><span class='comment'>{- |
<a name="line-4"></a> Module : Control.Arrow.IOListArrow
<a name="line-5"></a> Copyright : Copyright (C) 2005 Uwe Schmidt
<a name="line-6"></a> License : MIT
<a name="line-7"></a>
<a name="line-8"></a> Maintainer : Uwe Schmidt (uwe\@fh-wedel.de)
<a name="line-9"></a> Stability : experimental
<a name="line-10"></a> Portability: portable
<a name="line-11"></a>
<a name="line-12"></a> Implementation of pure list arrows with IO
<a name="line-13"></a>
<a name="line-14"></a>-}</span>
<a name="line-15"></a>
<a name="line-16"></a><span class='comment'>-- ------------------------------------------------------------</span>
<a name="line-17"></a>
<a name="line-18"></a><span class='keyword'>module</span> <span class='conid'>Control</span><span class='varop'>.</span><span class='conid'>Arrow</span><span class='varop'>.</span><span class='conid'>IOListArrow</span>
<a name="line-19"></a> <span class='layout'>(</span> <span class='conid'>IOLA</span><span class='layout'>(</span><span class='keyglyph'>..</span><span class='layout'>)</span>
<a name="line-20"></a> <span class='layout'>)</span>
<a name="line-21"></a><span class='keyword'>where</span>
<a name="line-22"></a>
<a name="line-23"></a><span class='keyword'>import</span> <span class='conid'>Control</span><span class='varop'>.</span><span class='conid'>Arrow</span>
<a name="line-24"></a><span class='keyword'>import</span> <span class='conid'>Control</span><span class='varop'>.</span><span class='conid'>Arrow</span><span class='varop'>.</span><span class='conid'>ArrowList</span>
<a name="line-25"></a><span class='keyword'>import</span> <span class='conid'>Control</span><span class='varop'>.</span><span class='conid'>Arrow</span><span class='varop'>.</span><span class='conid'>ArrowIf</span>
<a name="line-26"></a><span class='keyword'>import</span> <span class='conid'>Control</span><span class='varop'>.</span><span class='conid'>Arrow</span><span class='varop'>.</span><span class='conid'>ArrowTree</span>
<a name="line-27"></a><span class='keyword'>import</span> <span class='conid'>Control</span><span class='varop'>.</span><span class='conid'>Arrow</span><span class='varop'>.</span><span class='conid'>ArrowIO</span>
<a name="line-28"></a>
<a name="line-29"></a><span class='comment'>-- ------------------------------------------------------------</span>
<a name="line-30"></a>
<a name="line-31"></a><span class='comment'>-- | list arrow combined with IO monad</span>
<a name="line-32"></a>
<a name="line-33"></a><a name="IOLA"></a><span class='keyword'>newtype</span> <span class='conid'>IOLA</span> <span class='varid'>a</span> <span class='varid'>b</span> <span class='keyglyph'>=</span> <span class='conid'>IOLA</span> <span class='layout'>{</span> <span class='varid'>runIOLA</span> <span class='keyglyph'>::</span> <span class='varid'>a</span> <span class='keyglyph'>-></span> <span class='conid'>IO</span> <span class='keyglyph'>[</span><span class='varid'>b</span><span class='keyglyph'>]</span> <span class='layout'>}</span>
<a name="line-34"></a>
<a name="line-35"></a><span class='keyword'>instance</span> <span class='conid'>Arrow</span> <span class='conid'>IOLA</span> <span class='keyword'>where</span>
<a name="line-36"></a> <span class='varid'>arr</span> <span class='varid'>f</span> <span class='keyglyph'>=</span> <span class='conid'>IOLA</span> <span class='varop'>$</span> <span class='keyglyph'>\</span> <span class='varid'>x</span> <span class='keyglyph'>-></span> <span class='varid'>return</span> <span class='keyglyph'>[</span><span class='varid'>f</span> <span class='varid'>x</span><span class='keyglyph'>]</span>
<a name="line-37"></a>
<a name="line-38"></a> <span class='conid'>IOLA</span> <span class='varid'>f</span> <span class='varop'>>>></span> <span class='conid'>IOLA</span> <span class='varid'>g</span> <span class='keyglyph'>=</span> <span class='conid'>IOLA</span> <span class='varop'>$</span> <span class='keyglyph'>\</span> <span class='varid'>x</span> <span class='keyglyph'>-></span> <span class='keyword'>do</span>
<a name="line-39"></a> <span class='varid'>ys</span> <span class='keyglyph'><-</span> <span class='varid'>f</span> <span class='varid'>x</span>
<a name="line-40"></a> <span class='varid'>zs</span> <span class='keyglyph'><-</span> <span class='varid'>sequence</span> <span class='varop'>.</span> <span class='varid'>map</span> <span class='varid'>g</span> <span class='varop'>$</span> <span class='varid'>ys</span>
<a name="line-41"></a> <span class='varid'>return</span> <span class='layout'>(</span><span class='varid'>concat</span> <span class='varid'>zs</span><span class='layout'>)</span>
<a name="line-42"></a>
<a name="line-43"></a> <span class='varid'>first</span> <span class='layout'>(</span><span class='conid'>IOLA</span> <span class='varid'>f</span><span class='layout'>)</span> <span class='keyglyph'>=</span> <span class='conid'>IOLA</span> <span class='varop'>$</span> <span class='keyglyph'>\</span> <span class='keyglyph'>~</span><span class='layout'>(</span><span class='varid'>x1</span><span class='layout'>,</span> <span class='varid'>x2</span><span class='layout'>)</span> <span class='keyglyph'>-></span> <span class='keyword'>do</span>
<a name="line-44"></a> <span class='varid'>ys1</span> <span class='keyglyph'><-</span> <span class='varid'>f</span> <span class='varid'>x1</span>
<a name="line-45"></a> <span class='varid'>return</span> <span class='keyglyph'>[</span> <span class='layout'>(</span><span class='varid'>y1</span><span class='layout'>,</span> <span class='varid'>x2</span><span class='layout'>)</span> <span class='keyglyph'>|</span> <span class='varid'>y1</span> <span class='keyglyph'><-</span> <span class='varid'>ys1</span> <span class='keyglyph'>]</span>
<a name="line-46"></a>
<a name="line-47"></a> <span class='comment'>-- just for efficiency</span>
<a name="line-48"></a> <span class='varid'>second</span> <span class='layout'>(</span><span class='conid'>IOLA</span> <span class='varid'>g</span><span class='layout'>)</span> <span class='keyglyph'>=</span> <span class='conid'>IOLA</span> <span class='varop'>$</span> <span class='keyglyph'>\</span> <span class='keyglyph'>~</span><span class='layout'>(</span><span class='varid'>x1</span><span class='layout'>,</span> <span class='varid'>x2</span><span class='layout'>)</span> <span class='keyglyph'>-></span> <span class='keyword'>do</span>
<a name="line-49"></a> <span class='varid'>ys2</span> <span class='keyglyph'><-</span> <span class='varid'>g</span> <span class='varid'>x2</span>
<a name="line-50"></a> <span class='varid'>return</span> <span class='keyglyph'>[</span> <span class='layout'>(</span><span class='varid'>x1</span><span class='layout'>,</span> <span class='varid'>y2</span><span class='layout'>)</span> <span class='keyglyph'>|</span> <span class='varid'>y2</span> <span class='keyglyph'><-</span> <span class='varid'>ys2</span> <span class='keyglyph'>]</span>
<a name="line-51"></a>
<a name="line-52"></a> <span class='comment'>-- just for efficiency</span>
<a name="line-53"></a> <span class='conid'>IOLA</span> <span class='varid'>f</span> <span class='varop'>***</span> <span class='conid'>IOLA</span> <span class='varid'>g</span> <span class='keyglyph'>=</span> <span class='conid'>IOLA</span> <span class='varop'>$</span> <span class='keyglyph'>\</span> <span class='keyglyph'>~</span><span class='layout'>(</span><span class='varid'>x1</span><span class='layout'>,</span> <span class='varid'>x2</span><span class='layout'>)</span> <span class='keyglyph'>-></span> <span class='keyword'>do</span>
<a name="line-54"></a> <span class='varid'>ys1</span> <span class='keyglyph'><-</span> <span class='varid'>f</span> <span class='varid'>x1</span>
<a name="line-55"></a> <span class='varid'>ys2</span> <span class='keyglyph'><-</span> <span class='varid'>g</span> <span class='varid'>x2</span>
<a name="line-56"></a> <span class='varid'>return</span> <span class='keyglyph'>[</span> <span class='layout'>(</span><span class='varid'>y1</span><span class='layout'>,</span> <span class='varid'>y2</span><span class='layout'>)</span> <span class='keyglyph'>|</span> <span class='varid'>y1</span> <span class='keyglyph'><-</span> <span class='varid'>ys1</span><span class='layout'>,</span> <span class='varid'>y2</span> <span class='keyglyph'><-</span> <span class='varid'>ys2</span> <span class='keyglyph'>]</span>
<a name="line-57"></a>
<a name="line-58"></a> <span class='comment'>-- just for efficiency</span>
<a name="line-59"></a> <span class='conid'>IOLA</span> <span class='varid'>f</span> <span class='varop'>&&&</span> <span class='conid'>IOLA</span> <span class='varid'>g</span> <span class='keyglyph'>=</span> <span class='conid'>IOLA</span> <span class='varop'>$</span> <span class='keyglyph'>\</span> <span class='varid'>x</span> <span class='keyglyph'>-></span> <span class='keyword'>do</span>
<a name="line-60"></a> <span class='varid'>ys1</span> <span class='keyglyph'><-</span> <span class='varid'>f</span> <span class='varid'>x</span>
<a name="line-61"></a> <span class='varid'>ys2</span> <span class='keyglyph'><-</span> <span class='varid'>g</span> <span class='varid'>x</span>
<a name="line-62"></a> <span class='varid'>return</span> <span class='keyglyph'>[</span> <span class='layout'>(</span><span class='varid'>y1</span><span class='layout'>,</span> <span class='varid'>y2</span><span class='layout'>)</span> <span class='keyglyph'>|</span> <span class='varid'>y1</span> <span class='keyglyph'><-</span> <span class='varid'>ys1</span><span class='layout'>,</span> <span class='varid'>y2</span> <span class='keyglyph'><-</span> <span class='varid'>ys2</span> <span class='keyglyph'>]</span>
<a name="line-63"></a>
<a name="line-64"></a>
<a name="line-65"></a><span class='keyword'>instance</span> <span class='conid'>ArrowZero</span> <span class='conid'>IOLA</span> <span class='keyword'>where</span>
<a name="line-66"></a> <span class='varid'>zeroArrow</span> <span class='keyglyph'>=</span> <span class='conid'>IOLA</span> <span class='varop'>$</span> <span class='varid'>const</span> <span class='layout'>(</span><span class='varid'>return</span> <span class='conid'>[]</span><span class='layout'>)</span>
<a name="line-67"></a>
<a name="line-68"></a>
<a name="line-69"></a><span class='keyword'>instance</span> <span class='conid'>ArrowPlus</span> <span class='conid'>IOLA</span> <span class='keyword'>where</span>
<a name="line-70"></a> <span class='conid'>IOLA</span> <span class='varid'>f</span> <span class='varop'><+></span> <span class='conid'>IOLA</span> <span class='varid'>g</span> <span class='keyglyph'>=</span> <span class='conid'>IOLA</span> <span class='varop'>$</span> <span class='keyglyph'>\</span> <span class='varid'>x</span> <span class='keyglyph'>-></span> <span class='keyword'>do</span>
<a name="line-71"></a> <span class='varid'>rs1</span> <span class='keyglyph'><-</span> <span class='varid'>f</span> <span class='varid'>x</span>
<a name="line-72"></a> <span class='varid'>rs2</span> <span class='keyglyph'><-</span> <span class='varid'>g</span> <span class='varid'>x</span>
<a name="line-73"></a> <span class='varid'>return</span> <span class='layout'>(</span><span class='varid'>rs1</span> <span class='varop'>++</span> <span class='varid'>rs2</span><span class='layout'>)</span>
<a name="line-74"></a>
<a name="line-75"></a>
<a name="line-76"></a><span class='keyword'>instance</span> <span class='conid'>ArrowChoice</span> <span class='conid'>IOLA</span> <span class='keyword'>where</span>
<a name="line-77"></a> <span class='varid'>left</span> <span class='layout'>(</span><span class='conid'>IOLA</span> <span class='varid'>f</span><span class='layout'>)</span> <span class='keyglyph'>=</span> <span class='conid'>IOLA</span> <span class='varop'>$</span> <span class='varid'>either</span>
<a name="line-78"></a> <span class='layout'>(</span><span class='keyglyph'>\</span> <span class='varid'>x</span> <span class='keyglyph'>-></span> <span class='varid'>f</span> <span class='varid'>x</span> <span class='varop'>>>=</span> <span class='layout'>(</span><span class='keyglyph'>\</span> <span class='varid'>y</span> <span class='keyglyph'>-></span> <span class='varid'>return</span> <span class='layout'>(</span><span class='varid'>map</span> <span class='conid'>Left</span> <span class='varid'>y</span><span class='layout'>)</span><span class='layout'>)</span><span class='layout'>)</span>
<a name="line-79"></a> <span class='layout'>(</span><span class='varid'>return</span> <span class='varop'>.</span> <span class='layout'>(</span><span class='conop'>:</span><span class='conid'>[]</span><span class='layout'>)</span> <span class='varop'>.</span> <span class='conid'>Right</span><span class='layout'>)</span>
<a name="line-80"></a> <span class='varid'>right</span> <span class='layout'>(</span><span class='conid'>IOLA</span> <span class='varid'>f</span><span class='layout'>)</span> <span class='keyglyph'>=</span> <span class='conid'>IOLA</span> <span class='varop'>$</span> <span class='varid'>either</span>
<a name="line-81"></a> <span class='layout'>(</span><span class='varid'>return</span> <span class='varop'>.</span> <span class='layout'>(</span><span class='conop'>:</span><span class='conid'>[]</span><span class='layout'>)</span> <span class='varop'>.</span> <span class='conid'>Left</span><span class='layout'>)</span>
<a name="line-82"></a> <span class='layout'>(</span><span class='keyglyph'>\</span> <span class='varid'>x</span> <span class='keyglyph'>-></span> <span class='varid'>f</span> <span class='varid'>x</span> <span class='varop'>>>=</span> <span class='layout'>(</span><span class='keyglyph'>\</span> <span class='varid'>y</span> <span class='keyglyph'>-></span> <span class='varid'>return</span> <span class='layout'>(</span><span class='varid'>map</span> <span class='conid'>Right</span> <span class='varid'>y</span><span class='layout'>)</span><span class='layout'>)</span><span class='layout'>)</span>
<a name="line-83"></a>
<a name="line-84"></a><span class='keyword'>instance</span> <span class='conid'>ArrowApply</span> <span class='conid'>IOLA</span> <span class='keyword'>where</span>
<a name="line-85"></a> <span class='varid'>app</span> <span class='keyglyph'>=</span> <span class='conid'>IOLA</span> <span class='varop'>$</span> <span class='keyglyph'>\</span> <span class='layout'>(</span><span class='conid'>IOLA</span> <span class='varid'>f</span><span class='layout'>,</span> <span class='varid'>x</span><span class='layout'>)</span> <span class='keyglyph'>-></span> <span class='varid'>f</span> <span class='varid'>x</span>
<a name="line-86"></a>
<a name="line-87"></a><span class='keyword'>instance</span> <span class='conid'>ArrowList</span> <span class='conid'>IOLA</span> <span class='keyword'>where</span>
<a name="line-88"></a> <span class='varid'>arrL</span> <span class='varid'>f</span> <span class='keyglyph'>=</span> <span class='conid'>IOLA</span> <span class='varop'>$</span> <span class='keyglyph'>\</span> <span class='varid'>x</span> <span class='keyglyph'>-></span> <span class='varid'>return</span> <span class='layout'>(</span><span class='varid'>f</span> <span class='varid'>x</span><span class='layout'>)</span>
<a name="line-89"></a> <span class='varid'>arr2A</span> <span class='varid'>f</span> <span class='keyglyph'>=</span> <span class='conid'>IOLA</span> <span class='varop'>$</span> <span class='keyglyph'>\</span> <span class='keyglyph'>~</span><span class='layout'>(</span><span class='varid'>x</span><span class='layout'>,</span> <span class='varid'>y</span><span class='layout'>)</span> <span class='keyglyph'>-></span> <span class='varid'>runIOLA</span> <span class='layout'>(</span><span class='varid'>f</span> <span class='varid'>x</span><span class='layout'>)</span> <span class='varid'>y</span>
<a name="line-90"></a> <span class='varid'>constA</span> <span class='varid'>c</span> <span class='keyglyph'>=</span> <span class='conid'>IOLA</span> <span class='varop'>$</span> <span class='varid'>const</span> <span class='layout'>(</span><span class='varid'>return</span> <span class='keyglyph'>[</span><span class='varid'>c</span><span class='keyglyph'>]</span><span class='layout'>)</span>
<a name="line-91"></a> <span class='varid'>isA</span> <span class='varid'>p</span> <span class='keyglyph'>=</span> <span class='conid'>IOLA</span> <span class='varop'>$</span> <span class='keyglyph'>\</span><span class='varid'>x</span> <span class='keyglyph'>-></span> <span class='varid'>return</span> <span class='layout'>(</span><span class='keyword'>if</span> <span class='varid'>p</span> <span class='varid'>x</span> <span class='keyword'>then</span> <span class='keyglyph'>[</span><span class='varid'>x</span><span class='keyglyph'>]</span> <span class='keyword'>else</span> <span class='conid'>[]</span><span class='layout'>)</span>
<a name="line-92"></a> <span class='conid'>IOLA</span> <span class='varid'>f</span> <span class='varop'>>>.</span> <span class='varid'>g</span> <span class='keyglyph'>=</span> <span class='conid'>IOLA</span> <span class='varop'>$</span> <span class='keyglyph'>\</span><span class='varid'>x</span> <span class='keyglyph'>-></span> <span class='keyword'>do</span>
<a name="line-93"></a> <span class='varid'>ys</span> <span class='keyglyph'><-</span> <span class='varid'>f</span> <span class='varid'>x</span>
<a name="line-94"></a> <span class='varid'>return</span> <span class='layout'>(</span><span class='varid'>g</span> <span class='varid'>ys</span><span class='layout'>)</span>
<a name="line-95"></a>
<a name="line-96"></a>
<a name="line-97"></a><span class='keyword'>instance</span> <span class='conid'>ArrowIf</span> <span class='conid'>IOLA</span> <span class='keyword'>where</span>
<a name="line-98"></a> <span class='varid'>ifA</span> <span class='layout'>(</span><span class='conid'>IOLA</span> <span class='varid'>p</span><span class='layout'>)</span> <span class='varid'>ta</span> <span class='varid'>ea</span> <span class='keyglyph'>=</span> <span class='conid'>IOLA</span> <span class='varop'>$</span> <span class='keyglyph'>\</span><span class='varid'>x</span> <span class='keyglyph'>-></span> <span class='keyword'>do</span>
<a name="line-99"></a> <span class='varid'>res</span> <span class='keyglyph'><-</span> <span class='varid'>p</span> <span class='varid'>x</span>
<a name="line-100"></a> <span class='varid'>runIOLA</span> <span class='layout'>(</span><span class='keyword'>if</span> <span class='varid'>null</span> <span class='varid'>res</span> <span class='keyword'>then</span> <span class='varid'>ea</span> <span class='keyword'>else</span> <span class='varid'>ta</span><span class='layout'>)</span> <span class='varid'>x</span>
<a name="line-101"></a> <span class='layout'>(</span><span class='conid'>IOLA</span> <span class='varid'>f</span><span class='layout'>)</span> <span class='varop'>`orElse`</span> <span class='varid'>g</span>
<a name="line-102"></a> <span class='keyglyph'>=</span> <span class='conid'>IOLA</span> <span class='varop'>$</span> <span class='keyglyph'>\</span><span class='varid'>x</span> <span class='keyglyph'>-></span> <span class='keyword'>do</span>
<a name="line-103"></a> <span class='varid'>res</span> <span class='keyglyph'><-</span> <span class='varid'>f</span> <span class='varid'>x</span>
<a name="line-104"></a> <span class='keyword'>if</span> <span class='varid'>null</span> <span class='varid'>res</span> <span class='keyword'>then</span> <span class='varid'>runIOLA</span> <span class='varid'>g</span> <span class='varid'>x</span> <span class='keyword'>else</span> <span class='varid'>return</span> <span class='varid'>res</span>
<a name="line-105"></a>
<a name="line-106"></a><span class='keyword'>instance</span> <span class='conid'>ArrowIO</span> <span class='conid'>IOLA</span> <span class='keyword'>where</span>
<a name="line-107"></a> <span class='varid'>arrIO</span> <span class='varid'>cmd</span> <span class='keyglyph'>=</span> <span class='conid'>IOLA</span> <span class='varop'>$</span> <span class='keyglyph'>\</span><span class='varid'>x</span> <span class='keyglyph'>-></span> <span class='keyword'>do</span>
<a name="line-108"></a> <span class='varid'>res</span> <span class='keyglyph'><-</span> <span class='varid'>cmd</span> <span class='varid'>x</span>
<a name="line-109"></a> <span class='varid'>return</span> <span class='keyglyph'>[</span><span class='varid'>res</span><span class='keyglyph'>]</span>
<a name="line-110"></a>
<a name="line-111"></a><span class='keyword'>instance</span> <span class='conid'>ArrowIOIf</span> <span class='conid'>IOLA</span> <span class='keyword'>where</span>
<a name="line-112"></a> <span class='varid'>isIOA</span> <span class='varid'>p</span> <span class='keyglyph'>=</span> <span class='conid'>IOLA</span> <span class='varop'>$</span> <span class='keyglyph'>\</span><span class='varid'>x</span> <span class='keyglyph'>-></span> <span class='keyword'>do</span>
<a name="line-113"></a> <span class='varid'>res</span> <span class='keyglyph'><-</span> <span class='varid'>p</span> <span class='varid'>x</span>
<a name="line-114"></a> <span class='varid'>return</span> <span class='layout'>(</span><span class='keyword'>if</span> <span class='varid'>res</span> <span class='keyword'>then</span> <span class='keyglyph'>[</span><span class='varid'>x</span><span class='keyglyph'>]</span> <span class='keyword'>else</span> <span class='conid'>[]</span><span class='layout'>)</span>
<a name="line-115"></a>
<a name="line-116"></a><span class='keyword'>instance</span> <span class='conid'>ArrowTree</span> <span class='conid'>IOLA</span>
<a name="line-117"></a>
<a name="line-118"></a><span class='comment'>-- ------------------------------------------------------------</span>
</pre></body>
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