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<title>src/Hint/Structure.hs</title>
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<pre><a name="line-1"></a><span class='hs-comment'>{-# LANGUAGE ViewPatterns, PatternGuards #-}</span>
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<a name="line-3"></a><span class='hs-comment'>{-
<a name="line-4"></a> Improve the structure of code
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<a name="line-6"></a><TEST>
<a name="line-7"></a>yes x y = if a then b else if c then d else e -- yes x y ; | a = b ; | c = d ; | otherwise = e
<a name="line-8"></a>no x y = if a then b else c
<a name="line-9"></a>foo b | c <- f b = c -- foo (f -> c) = c
<a name="line-10"></a>foo x y b z | c:cs <- f g b = c -- foo x y (f g -> c:cs) z = c
<a name="line-11"></a>foo b | c <- f b = c + b
<a name="line-12"></a>foo b | c <- f b = c where f = here
<a name="line-13"></a>foo b | c <- f b = c where foo = b
<a name="line-14"></a>foo b | c <- f b = c \
<a name="line-15"></a> | c <- f b = c
<a name="line-16"></a></TEST>
<a name="line-17"></a>-}</span>
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<a name="line-20"></a><span class='hs-keyword'>module</span> <span class='hs-conid'>Hint</span><span class='hs-varop'>.</span><span class='hs-conid'>Structure</span> <span class='hs-keyword'>where</span>
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<a name="line-22"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Hint</span><span class='hs-varop'>.</span><span class='hs-conid'>Type</span>
<a name="line-23"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Util</span>
<a name="line-24"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>List</span>
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<a name="line-27"></a><a name="structureHint"></a><span class='hs-definition'>structureHint</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>DeclHint</span>
<a name="line-28"></a><span class='hs-definition'>structureHint</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'>concat</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>concatMap</span> <span class='hs-varid'>useGuards</span> <span class='hs-varid'>xs</span> <span class='hs-keyglyph'>|</span> <span class='hs-conid'>FunBind</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>xs</span> <span class='hs-keyglyph'><-</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>x</span><span class='hs-keyglyph'>]</span><span class='hs-keyglyph'>]</span>
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<a name="line-31"></a><a name="useGuards"></a><span class='hs-definition'>useGuards</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Match</span> <span class='hs-conid'>S</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Idea</span><span class='hs-keyglyph'>]</span>
<a name="line-32"></a><span class='hs-definition'>useGuards</span> <span class='hs-varid'>x</span><span class='hs-keyglyph'>@</span><span class='hs-layout'>(</span><span class='hs-conid'>Match</span> <span class='hs-varid'>a</span> <span class='hs-varid'>b</span> <span class='hs-varid'>c</span> <span class='hs-layout'>(</span><span class='hs-conid'>UnGuardedRhs</span> <span class='hs-varid'>d</span> <span class='hs-varid'>bod</span><span class='hs-layout'>)</span> <span class='hs-varid'>e</span><span class='hs-layout'>)</span>
<a name="line-33"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>length</span> <span class='hs-varid'>guards</span> <span class='hs-varop'>></span> <span class='hs-num'>2</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>warn</span> <span class='hs-str'>"Use guards"</span> <span class='hs-varid'>x</span> <span class='hs-varid'>x2</span><span class='hs-keyglyph'>]</span>
<a name="line-34"></a> <span class='hs-keyword'>where</span>
<a name="line-35"></a> <span class='hs-varid'>guards</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>asGuards</span> <span class='hs-varid'>bod</span>
<a name="line-36"></a> <span class='hs-varid'>x2</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Match</span> <span class='hs-varid'>a</span> <span class='hs-varid'>b</span> <span class='hs-varid'>c</span> <span class='hs-layout'>(</span><span class='hs-conid'>GuardedRhss</span> <span class='hs-varid'>d</span> <span class='hs-varid'>guards</span><span class='hs-layout'>)</span> <span class='hs-varid'>e</span>
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<a name="line-38"></a><span class='hs-definition'>useGuards</span> <span class='hs-varid'>o</span><span class='hs-keyglyph'>@</span><span class='hs-layout'>(</span><span class='hs-conid'>Match</span> <span class='hs-varid'>sl</span> <span class='hs-varid'>b</span> <span class='hs-varid'>pats</span> <span class='hs-layout'>(</span><span class='hs-conid'>GuardedRhss</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>GuardedRhs</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Generator</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>pat</span> <span class='hs-layout'>(</span><span class='hs-conid'>App</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>op</span> <span class='hs-layout'>(</span><span class='hs-varid'>view</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Var_</span> <span class='hs-varid'>p</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span><span class='hs-keyglyph'>]</span> <span class='hs-varid'>bod</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>)</span> <span class='hs-varid'>decs</span><span class='hs-layout'>)</span>
<a name="line-39"></a> <span class='hs-keyglyph'>|</span> <span class='hs-conid'>Just</span> <span class='hs-varid'>i</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>findIndex</span> <span class='hs-layout'>(</span><span class='hs-varop'>=~=</span> <span class='hs-layout'>(</span><span class='hs-varid'>toNamed</span> <span class='hs-varid'>p</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Pat_</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-varid'>pats</span>
<a name="line-40"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>p</span> <span class='hs-varop'>`notElem`</span> <span class='hs-layout'>(</span><span class='hs-varid'>vars</span> <span class='hs-varid'>bod</span> <span class='hs-varop'>++</span> <span class='hs-varid'>vars</span> <span class='hs-varid'>decs</span><span class='hs-layout'>)</span>
<a name="line-41"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>vars</span> <span class='hs-varid'>op</span> <span class='hs-varop'>`disjoint`</span> <span class='hs-varid'>decsBind</span><span class='hs-layout'>,</span> <span class='hs-varid'>pvars</span> <span class='hs-varid'>pats</span> <span class='hs-varop'>`disjoint`</span> <span class='hs-varid'>vars</span> <span class='hs-varid'>op</span><span class='hs-layout'>,</span> <span class='hs-varid'>pvars</span> <span class='hs-varid'>pat</span> <span class='hs-varop'>`disjoint`</span> <span class='hs-varid'>pvars</span> <span class='hs-varid'>pats</span>
<a name="line-42"></a> <span class='hs-keyglyph'>=</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>warn</span> <span class='hs-str'>"Use view patterns"</span> <span class='hs-varid'>o</span> <span class='hs-varop'>$</span>
<a name="line-43"></a> <span class='hs-conid'>Match</span> <span class='hs-varid'>sl</span> <span class='hs-varid'>b</span> <span class='hs-layout'>(</span><span class='hs-varid'>take</span> <span class='hs-varid'>i</span> <span class='hs-varid'>pats</span> <span class='hs-varop'>++</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>PParen</span> <span class='hs-varid'>an</span> <span class='hs-varop'>$</span> <span class='hs-conid'>PViewPat</span> <span class='hs-varid'>an</span> <span class='hs-varid'>op</span> <span class='hs-varid'>pat</span><span class='hs-keyglyph'>]</span> <span class='hs-varop'>++</span> <span class='hs-varid'>drop</span> <span class='hs-layout'>(</span><span class='hs-varid'>i</span><span class='hs-varop'>+</span><span class='hs-num'>1</span><span class='hs-layout'>)</span> <span class='hs-varid'>pats</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-conid'>UnGuardedRhs</span> <span class='hs-varid'>an</span> <span class='hs-varid'>bod</span><span class='hs-layout'>)</span> <span class='hs-varid'>decs</span><span class='hs-keyglyph'>]</span>
<a name="line-44"></a> <span class='hs-keyword'>where</span>
<a name="line-45"></a> <span class='hs-varid'>decsBind</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>nub</span> <span class='hs-varop'>$</span> <span class='hs-varid'>concatMap</span> <span class='hs-varid'>declBind</span> <span class='hs-varop'>$</span> <span class='hs-varid'>childrenBi</span> <span class='hs-varid'>decs</span>
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<a name="line-47"></a><span class='hs-definition'>useGuards</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>[]</span>
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<a name="line-50"></a><a name="asGuards"></a><span class='hs-definition'>asGuards</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Exp_</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>GuardedRhs</span> <span class='hs-conid'>S</span><span class='hs-keyglyph'>]</span>
<a name="line-51"></a><span class='hs-definition'>asGuards</span> <span class='hs-layout'>(</span><span class='hs-conid'>Paren</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>x</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>asGuards</span> <span class='hs-varid'>x</span>
<a name="line-52"></a><span class='hs-definition'>asGuards</span> <span class='hs-layout'>(</span><span class='hs-conid'>If</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>a</span> <span class='hs-varid'>b</span> <span class='hs-varid'>c</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>GuardedRhs</span> <span class='hs-varid'>an</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Qualifier</span> <span class='hs-varid'>an</span> <span class='hs-varid'>a</span><span class='hs-keyglyph'>]</span> <span class='hs-varid'>b</span> <span class='hs-conop'>:</span> <span class='hs-varid'>asGuards</span> <span class='hs-varid'>c</span>
<a name="line-53"></a><span class='hs-definition'>asGuards</span> <span class='hs-varid'>x</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>GuardedRhs</span> <span class='hs-varid'>an</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Qualifier</span> <span class='hs-varid'>an</span> <span class='hs-varop'>$</span> <span class='hs-varid'>toNamed</span> <span class='hs-str'>"otherwise"</span><span class='hs-keyglyph'>]</span> <span class='hs-varid'>x</span><span class='hs-keyglyph'>]</span>
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