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<title>System/Console/CmdArgs/Explicit/ExpandArgsAt.hs</title>
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<pre><a name="line-1"></a><span class='hs-comment'>{-# LANGUAGE RecordWildCards #-}</span>
<a name="line-2"></a><span class='hs-keyword'>module</span> <span class='hs-conid'>System</span><span class='hs-varop'>.</span><span class='hs-conid'>Console</span><span class='hs-varop'>.</span><span class='hs-conid'>CmdArgs</span><span class='hs-varop'>.</span><span class='hs-conid'>Explicit</span><span class='hs-varop'>.</span><span class='hs-conid'>ExpandArgsAt</span><span class='hs-layout'>(</span><span class='hs-varid'>expandArgsAt</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-3"></a>
<a name="line-4"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>System</span><span class='hs-varop'>.</span><span class='hs-conid'>FilePath</span>
<a name="line-5"></a>
<a name="line-6"></a>
<a name="line-7"></a><a name="expandArgsAt"></a><span class='hs-comment'>-- | Expand @\@@ directives in a list of arguments, usually obtained from 'getArgs'.</span>
<a name="line-8"></a><span class='hs-comment'>-- As an example, given the file @test.txt@ with the lines @hello@ and @world@:</span>
<a name="line-9"></a><span class='hs-comment'>--</span>
<a name="line-10"></a><span class='hs-comment'>-- > expandArgsAt ["@test.txt","!"] == ["hello","world","!"]</span>
<a name="line-11"></a><span class='hs-comment'>--</span>
<a name="line-12"></a><span class='hs-comment'>-- Any @\@@ directives in the files will be recursively expanded (raising an error</span>
<a name="line-13"></a><span class='hs-comment'>-- if there is infinite recursion).</span>
<a name="line-14"></a><span class='hs-definition'>expandArgsAt</span> <span class='hs-keyglyph'>::</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>String</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>String</span><span class='hs-keyglyph'>]</span>
<a name="line-15"></a><span class='hs-definition'>expandArgsAt</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>fmap</span> <span class='hs-varid'>concat</span> <span class='hs-varop'>.</span> <span class='hs-varid'>mapM</span> <span class='hs-layout'>(</span><span class='hs-varid'>f</span> <span class='hs-conid'>[]</span> <span class='hs-str'>"."</span><span class='hs-layout'>)</span>
<a name="line-16"></a> <span class='hs-keyword'>where</span>
<a name="line-17"></a> <span class='hs-varid'>f</span> <span class='hs-varid'>seen</span> <span class='hs-varid'>dir</span> <span class='hs-layout'>(</span><span class='hs-chr'>'@'</span><span class='hs-conop'>:</span><span class='hs-varid'>x</span><span class='hs-layout'>)</span>
<a name="line-18"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>x</span> <span class='hs-varop'>`elem`</span> <span class='hs-varid'>seen</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>error</span> <span class='hs-varop'>$</span> <span class='hs-varid'>unlines</span> <span class='hs-varop'>$</span>
<a name="line-19"></a> <span class='hs-str'>"System.Console.CmdArgs.Explicit.expandArgsAt, recursion in @ directives:"</span> <span class='hs-conop'>:</span>
<a name="line-20"></a> <span class='hs-varid'>map</span> <span class='hs-layout'>(</span><span class='hs-str'>" "</span><span class='hs-varop'>++</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>reverse</span> <span class='hs-varop'>$</span> <span class='hs-varid'>x</span><span class='hs-conop'>:</span><span class='hs-varid'>seen</span><span class='hs-layout'>)</span>
<a name="line-21"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>length</span> <span class='hs-varid'>seen</span> <span class='hs-varop'>></span> <span class='hs-num'>15</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>error</span> <span class='hs-varop'>$</span> <span class='hs-varid'>unlines</span> <span class='hs-varop'>$</span>
<a name="line-22"></a> <span class='hs-str'>"System.Console.CmdArgs.Explicit.expandArgsAt, over 15 @ directives deep:"</span> <span class='hs-conop'>:</span>
<a name="line-23"></a> <span class='hs-varid'>map</span> <span class='hs-layout'>(</span><span class='hs-str'>" "</span><span class='hs-varop'>++</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>reverse</span> <span class='hs-varid'>seen</span><span class='hs-layout'>)</span>
<a name="line-24"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>otherwise</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span>
<a name="line-25"></a> <span class='hs-varid'>src</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>readFile</span> <span class='hs-varop'>$</span> <span class='hs-varid'>dir</span> <span class='hs-varop'></></span> <span class='hs-varid'>x</span>
<a name="line-26"></a> <span class='hs-varid'>fmap</span> <span class='hs-varid'>concat</span> <span class='hs-varop'>$</span> <span class='hs-varid'>mapM</span> <span class='hs-layout'>(</span><span class='hs-varid'>f</span> <span class='hs-layout'>(</span><span class='hs-varid'>x</span><span class='hs-conop'>:</span><span class='hs-varid'>seen</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>takeDirectory</span> <span class='hs-varid'>x</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-varop'>$</span> <span class='hs-varid'>lines</span> <span class='hs-varid'>src</span>
<a name="line-27"></a> <span class='hs-varid'>f</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>x</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>return</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>x</span><span class='hs-keyglyph'>]</span>
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