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<pre><a name="line-1"></a><span class='hs-comment'>{-# LANGUAGE PatternGuards, TypeSynonymInstances #-}</span>
<a name="line-2"></a>
<a name="line-3"></a><span class='hs-keyword'>module</span> <span class='hs-conid'>HSE</span><span class='hs-varop'>.</span><span class='hs-conid'>Bracket</span> <span class='hs-keyword'>where</span>
<a name="line-4"></a>
<a name="line-5"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>HSE</span><span class='hs-varop'>.</span><span class='hs-conid'>Type</span>
<a name="line-6"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>HSE</span><span class='hs-varop'>.</span><span class='hs-conid'>Util</span>
<a name="line-7"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Util</span>
<a name="line-8"></a>
<a name="line-9"></a>
<a name="line-10"></a><a name="Brackets"></a><span class='hs-keyword'>class</span> <span class='hs-conid'>Brackets</span> <span class='hs-varid'>a</span> <span class='hs-keyword'>where</span>
<a name="line-11"></a> <span class='hs-varid'>remParen</span> <span class='hs-keyglyph'>::</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Maybe</span> <span class='hs-varid'>a</span> <span class='hs-comment'>-- remove one paren, or Nothing if there is no paren</span>
<a name="line-12"></a> <span class='hs-varid'>addParen</span> <span class='hs-keyglyph'>::</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>a</span> <span class='hs-comment'>-- write out a paren</span>
<a name="line-13"></a>
<a name="line-14"></a> <span class='hs-comment'>-- | Is this item lexically requiring no bracketing ever</span>
<a name="line-15"></a> <span class='hs-comment'>-- i.e. is totally atomic</span>
<a name="line-16"></a> <span class='hs-varid'>isAtom</span> <span class='hs-keyglyph'>::</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Bool</span>
<a name="line-17"></a>
<a name="line-18"></a> <span class='hs-comment'>-- | Is the child safe free from brackets in the parent position.</span>
<a name="line-19"></a> <span class='hs-comment'>-- Err on the side of caution, True = don't know</span>
<a name="line-20"></a> <span class='hs-varid'>needBracket</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Int</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Bool</span>
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<a name="line-22"></a>
<a name="line-23"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>Brackets</span> <span class='hs-conid'>Exp_</span> <span class='hs-keyword'>where</span>
<a name="line-24"></a> <span class='hs-varid'>remParen</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-conid'>Just</span> <span class='hs-varid'>x</span>
<a name="line-25"></a> <span class='hs-varid'>remParen</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Nothing</span>
<a name="line-26"></a> <span class='hs-varid'>addParen</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Paren</span> <span class='hs-varid'>an</span>
<a name="line-27"></a>
<a name="line-28"></a> <span class='hs-varid'>isAtom</span> <span class='hs-varid'>x</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>case</span> <span class='hs-varid'>x</span> <span class='hs-keyword'>of</span>
<a name="line-29"></a> <span class='hs-conid'>Paren</span><span class='hs-layout'>{</span><span class='hs-layout'>}</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>True</span>
<a name="line-30"></a> <span class='hs-conid'>Tuple</span><span class='hs-layout'>{</span><span class='hs-layout'>}</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>True</span>
<a name="line-31"></a> <span class='hs-conid'>List</span><span class='hs-layout'>{</span><span class='hs-layout'>}</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>True</span>
<a name="line-32"></a> <span class='hs-conid'>LeftSection</span><span class='hs-layout'>{</span><span class='hs-layout'>}</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>True</span>
<a name="line-33"></a> <span class='hs-conid'>RightSection</span><span class='hs-layout'>{</span><span class='hs-layout'>}</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>True</span>
<a name="line-34"></a> <span class='hs-conid'>RecConstr</span><span class='hs-layout'>{</span><span class='hs-layout'>}</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>True</span>
<a name="line-35"></a> <span class='hs-conid'>ListComp</span><span class='hs-layout'>{</span><span class='hs-layout'>}</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>True</span>
<a name="line-36"></a> <span class='hs-conid'>EnumFrom</span><span class='hs-layout'>{</span><span class='hs-layout'>}</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>True</span>
<a name="line-37"></a> <span class='hs-conid'>EnumFromTo</span><span class='hs-layout'>{</span><span class='hs-layout'>}</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>True</span>
<a name="line-38"></a> <span class='hs-conid'>EnumFromThen</span><span class='hs-layout'>{</span><span class='hs-layout'>}</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>True</span>
<a name="line-39"></a> <span class='hs-conid'>EnumFromThenTo</span><span class='hs-layout'>{</span><span class='hs-layout'>}</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>True</span>
<a name="line-40"></a> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>isLexeme</span> <span class='hs-varid'>x</span>
<a name="line-41"></a>
<a name="line-42"></a> <span class='hs-comment'>-- note: i is the index in children, not in the AST</span>
<a name="line-43"></a> <span class='hs-varid'>needBracket</span> <span class='hs-varid'>i</span> <span class='hs-varid'>parent</span> <span class='hs-varid'>child</span>
<a name="line-44"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>isAtom</span> <span class='hs-varid'>child</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>False</span>
<a name="line-45"></a> <span class='hs-keyglyph'>|</span> <span class='hs-conid'>InfixApp</span><span class='hs-layout'>{</span><span class='hs-layout'>}</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>parent</span><span class='hs-layout'>,</span> <span class='hs-conid'>App</span><span class='hs-layout'>{</span><span class='hs-layout'>}</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>child</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>False</span>
<a name="line-46"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>isSection</span> <span class='hs-varid'>parent</span><span class='hs-layout'>,</span> <span class='hs-conid'>App</span><span class='hs-layout'>{</span><span class='hs-layout'>}</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>child</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>False</span>
<a name="line-47"></a> <span class='hs-keyglyph'>|</span> <span class='hs-conid'>ListComp</span><span class='hs-layout'>{</span><span class='hs-layout'>}</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>parent</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>False</span>
<a name="line-48"></a> <span class='hs-keyglyph'>|</span> <span class='hs-conid'>List</span><span class='hs-layout'>{</span><span class='hs-layout'>}</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>parent</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>False</span>
<a name="line-49"></a> <span class='hs-keyglyph'>|</span> <span class='hs-conid'>Tuple</span><span class='hs-layout'>{</span><span class='hs-layout'>}</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>parent</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>False</span>
<a name="line-50"></a> <span class='hs-keyglyph'>|</span> <span class='hs-conid'>If</span><span class='hs-layout'>{</span><span class='hs-layout'>}</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>parent</span><span class='hs-layout'>,</span> <span class='hs-varid'>isAnyApp</span> <span class='hs-varid'>child</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>False</span>
<a name="line-51"></a> <span class='hs-keyglyph'>|</span> <span class='hs-conid'>App</span><span class='hs-layout'>{</span><span class='hs-layout'>}</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>parent</span><span class='hs-layout'>,</span> <span class='hs-varid'>i</span> <span class='hs-varop'>==</span> <span class='hs-num'>0</span><span class='hs-layout'>,</span> <span class='hs-conid'>App</span><span class='hs-layout'>{</span><span class='hs-layout'>}</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>child</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>False</span>
<a name="line-52"></a> <span class='hs-keyglyph'>|</span> <span class='hs-conid'>ExpTypeSig</span><span class='hs-layout'>{</span><span class='hs-layout'>}</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>parent</span><span class='hs-layout'>,</span> <span class='hs-varid'>i</span> <span class='hs-varop'>==</span> <span class='hs-num'>0</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>False</span>
<a name="line-53"></a> <span class='hs-keyglyph'>|</span> <span class='hs-conid'>Paren</span><span class='hs-layout'>{</span><span class='hs-layout'>}</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>parent</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>False</span>
<a name="line-54"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>isDotApp</span> <span class='hs-varid'>parent</span><span class='hs-layout'>,</span> <span class='hs-varid'>isDotApp</span> <span class='hs-varid'>child</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-keyglyph'>=</span> <span class='hs-conid'>False</span>
<a name="line-55"></a> <span class='hs-keyglyph'>|</span> <span class='hs-conid'>RecConstr</span><span class='hs-layout'>{</span><span class='hs-layout'>}</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>parent</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>False</span>
<a name="line-56"></a> <span class='hs-keyglyph'>|</span> <span class='hs-conid'>RecUpdate</span><span class='hs-layout'>{</span><span class='hs-layout'>}</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>parent</span><span class='hs-layout'>,</span> <span class='hs-varid'>i</span> <span class='hs-varop'>/=</span> <span class='hs-num'>0</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>False</span>
<a name="line-57"></a> <span class='hs-keyglyph'>|</span> <span class='hs-conid'>Lambda</span><span class='hs-layout'>{</span><span class='hs-layout'>}</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>parent</span><span class='hs-layout'>,</span> <span class='hs-varid'>i</span> <span class='hs-varop'>==</span> <span class='hs-varid'>length</span> <span class='hs-layout'>(</span><span class='hs-varid'>universeBi</span> <span class='hs-varid'>parent</span> <span class='hs-keyglyph'>::</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Pat_</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>)</span> <span class='hs-comment'>-</span> <span class='hs-num'>1</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>False</span> <span class='hs-comment'>-- watch out for PViewPat</span>
<a name="line-58"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>otherwise</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>True</span>
<a name="line-59"></a>
<a name="line-60"></a>
<a name="line-61"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>Brackets</span> <span class='hs-conid'>Type_</span> <span class='hs-keyword'>where</span>
<a name="line-62"></a> <span class='hs-varid'>remParen</span> <span class='hs-layout'>(</span><span class='hs-conid'>TyParen</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-conid'>Just</span> <span class='hs-varid'>x</span>
<a name="line-63"></a> <span class='hs-varid'>remParen</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Nothing</span>
<a name="line-64"></a> <span class='hs-varid'>addParen</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>TyParen</span> <span class='hs-varid'>an</span>
<a name="line-65"></a>
<a name="line-66"></a> <span class='hs-varid'>isAtom</span> <span class='hs-varid'>x</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>case</span> <span class='hs-varid'>x</span> <span class='hs-keyword'>of</span>
<a name="line-67"></a> <span class='hs-conid'>TyParen</span><span class='hs-layout'>{</span><span class='hs-layout'>}</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>True</span>
<a name="line-68"></a> <span class='hs-conid'>TyTuple</span><span class='hs-layout'>{</span><span class='hs-layout'>}</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>True</span>
<a name="line-69"></a> <span class='hs-conid'>TyList</span><span class='hs-layout'>{</span><span class='hs-layout'>}</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>True</span>
<a name="line-70"></a> <span class='hs-conid'>TyVar</span><span class='hs-layout'>{</span><span class='hs-layout'>}</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>True</span>
<a name="line-71"></a> <span class='hs-conid'>TyCon</span><span class='hs-layout'>{</span><span class='hs-layout'>}</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>True</span>
<a name="line-72"></a> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>False</span>
<a name="line-73"></a>
<a name="line-74"></a> <span class='hs-varid'>needBracket</span> <span class='hs-varid'>i</span> <span class='hs-varid'>parent</span> <span class='hs-varid'>child</span>
<a name="line-75"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>isAtom</span> <span class='hs-varid'>child</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>False</span>
<a name="line-76"></a> <span class='hs-keyglyph'>|</span> <span class='hs-conid'>TyFun</span><span class='hs-layout'>{</span><span class='hs-layout'>}</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>parent</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-conid'>TyFun</span><span class='hs-layout'>{</span><span class='hs-layout'>}</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>child</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>False</span>
<a name="line-77"></a> <span class='hs-keyglyph'>|</span> <span class='hs-conid'>TyFun</span><span class='hs-layout'>{</span><span class='hs-layout'>}</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>parent</span><span class='hs-layout'>,</span> <span class='hs-conid'>TyApp</span><span class='hs-layout'>{</span><span class='hs-layout'>}</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>child</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>False</span>
<a name="line-78"></a> <span class='hs-keyglyph'>|</span> <span class='hs-conid'>TyTuple</span><span class='hs-layout'>{</span><span class='hs-layout'>}</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>parent</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>False</span>
<a name="line-79"></a> <span class='hs-keyglyph'>|</span> <span class='hs-conid'>TyList</span><span class='hs-layout'>{</span><span class='hs-layout'>}</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>parent</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>False</span>
<a name="line-80"></a> <span class='hs-keyglyph'>|</span> <span class='hs-conid'>TyInfix</span><span class='hs-layout'>{</span><span class='hs-layout'>}</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>parent</span><span class='hs-layout'>,</span> <span class='hs-conid'>TyApp</span><span class='hs-layout'>{</span><span class='hs-layout'>}</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>child</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>False</span>
<a name="line-81"></a> <span class='hs-keyglyph'>|</span> <span class='hs-conid'>TyParen</span><span class='hs-layout'>{</span><span class='hs-layout'>}</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>parent</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>False</span>
<a name="line-82"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>otherwise</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>True</span>
<a name="line-83"></a>
<a name="line-84"></a>
<a name="line-85"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>Brackets</span> <span class='hs-conid'>Pat_</span> <span class='hs-keyword'>where</span>
<a name="line-86"></a> <span class='hs-varid'>remParen</span> <span class='hs-layout'>(</span><span class='hs-conid'>PParen</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-conid'>Just</span> <span class='hs-varid'>x</span>
<a name="line-87"></a> <span class='hs-varid'>remParen</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Nothing</span>
<a name="line-88"></a> <span class='hs-varid'>addParen</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>PParen</span> <span class='hs-varid'>an</span>
<a name="line-89"></a>
<a name="line-90"></a> <span class='hs-varid'>isAtom</span> <span class='hs-varid'>x</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>case</span> <span class='hs-varid'>x</span> <span class='hs-keyword'>of</span>
<a name="line-91"></a> <span class='hs-conid'>PParen</span><span class='hs-layout'>{</span><span class='hs-layout'>}</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>True</span>
<a name="line-92"></a> <span class='hs-conid'>PTuple</span><span class='hs-layout'>{</span><span class='hs-layout'>}</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>True</span>
<a name="line-93"></a> <span class='hs-conid'>PList</span><span class='hs-layout'>{</span><span class='hs-layout'>}</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>True</span>
<a name="line-94"></a> <span class='hs-conid'>PVar</span><span class='hs-layout'>{</span><span class='hs-layout'>}</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>True</span>
<a name="line-95"></a> <span class='hs-conid'>PApp</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span> <span class='hs-conid'>[]</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>True</span>
<a name="line-96"></a> <span class='hs-conid'>PWildCard</span><span class='hs-layout'>{</span><span class='hs-layout'>}</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>True</span>
<a name="line-97"></a> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>False</span>
<a name="line-98"></a>
<a name="line-99"></a> <span class='hs-varid'>needBracket</span> <span class='hs-varid'>i</span> <span class='hs-varid'>parent</span> <span class='hs-varid'>child</span>
<a name="line-100"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>isAtom</span> <span class='hs-varid'>child</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>False</span>
<a name="line-101"></a> <span class='hs-keyglyph'>|</span> <span class='hs-conid'>PTuple</span><span class='hs-layout'>{</span><span class='hs-layout'>}</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>parent</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>False</span>
<a name="line-102"></a> <span class='hs-keyglyph'>|</span> <span class='hs-conid'>PList</span><span class='hs-layout'>{</span><span class='hs-layout'>}</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>parent</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>False</span>
<a name="line-103"></a> <span class='hs-keyglyph'>|</span> <span class='hs-conid'>PInfixApp</span><span class='hs-layout'>{</span><span class='hs-layout'>}</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>parent</span><span class='hs-layout'>,</span> <span class='hs-conid'>PApp</span><span class='hs-layout'>{</span><span class='hs-layout'>}</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>child</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>False</span>
<a name="line-104"></a> <span class='hs-keyglyph'>|</span> <span class='hs-conid'>PParen</span><span class='hs-layout'>{</span><span class='hs-layout'>}</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>parent</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>False</span>
<a name="line-105"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>otherwise</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>True</span>
<a name="line-106"></a>
<a name="line-107"></a>
<a name="line-108"></a><a name="paren"></a><span class='hs-comment'>-- | Add a Paren around something if it is not atomic</span>
<a name="line-109"></a><span class='hs-definition'>paren</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Exp_</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Exp_</span>
<a name="line-110"></a><span class='hs-definition'>paren</span> <span class='hs-varid'>x</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>if</span> <span class='hs-varid'>isAtom</span> <span class='hs-varid'>x</span> <span class='hs-keyword'>then</span> <span class='hs-varid'>x</span> <span class='hs-keyword'>else</span> <span class='hs-varid'>addParen</span> <span class='hs-varid'>x</span>
<a name="line-111"></a>
<a name="line-112"></a>
<a name="line-113"></a><a name="descendBracket"></a><span class='hs-comment'>-- | Descend, and if something changes then add/remove brackets appropriately</span>
<a name="line-114"></a><span class='hs-definition'>descendBracket</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>Exp_</span> <span class='hs-keyglyph'>-></span> <span class='hs-layout'>(</span><span class='hs-conid'>Bool</span><span class='hs-layout'>,</span> <span class='hs-conid'>Exp_</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Exp_</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Exp_</span>
<a name="line-115"></a><span class='hs-definition'>descendBracket</span> <span class='hs-varid'>op</span> <span class='hs-varid'>x</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>descendIndex</span> <span class='hs-varid'>g</span> <span class='hs-varid'>x</span>
<a name="line-116"></a> <span class='hs-keyword'>where</span>
<a name="line-117"></a> <span class='hs-varid'>g</span> <span class='hs-varid'>i</span> <span class='hs-varid'>y</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>if</span> <span class='hs-varid'>a</span> <span class='hs-keyword'>then</span> <span class='hs-varid'>f</span> <span class='hs-varid'>i</span> <span class='hs-varid'>b</span> <span class='hs-keyword'>else</span> <span class='hs-varid'>b</span>
<a name="line-118"></a> <span class='hs-keyword'>where</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-varid'>op</span> <span class='hs-varid'>y</span>
<a name="line-119"></a>
<a name="line-120"></a> <span class='hs-varid'>f</span> <span class='hs-varid'>i</span> <span class='hs-layout'>(</span><span class='hs-conid'>Paren</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>y</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>not</span> <span class='hs-varop'>$</span> <span class='hs-varid'>needBracket</span> <span class='hs-varid'>i</span> <span class='hs-varid'>x</span> <span class='hs-varid'>y</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>y</span>
<a name="line-121"></a> <span class='hs-varid'>f</span> <span class='hs-varid'>i</span> <span class='hs-varid'>y</span> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>needBracket</span> <span class='hs-varid'>i</span> <span class='hs-varid'>x</span> <span class='hs-varid'>y</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>addParen</span> <span class='hs-varid'>y</span>
<a name="line-122"></a> <span class='hs-varid'>f</span> <span class='hs-varid'>i</span> <span class='hs-varid'>y</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>y</span>
<a name="line-123"></a>
<a name="line-124"></a>
<a name="line-125"></a><a name="transformBracket"></a><span class='hs-definition'>transformBracket</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>Exp_</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Maybe</span> <span class='hs-conid'>Exp_</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Exp_</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Exp_</span>
<a name="line-126"></a><span class='hs-definition'>transformBracket</span> <span class='hs-varid'>op</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>snd</span> <span class='hs-varop'>.</span> <span class='hs-varid'>g</span>
<a name="line-127"></a> <span class='hs-keyword'>where</span>
<a name="line-128"></a> <span class='hs-varid'>g</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>f</span> <span class='hs-varop'>.</span> <span class='hs-varid'>descendBracket</span> <span class='hs-varid'>g</span>
<a name="line-129"></a> <span class='hs-varid'>f</span> <span class='hs-varid'>x</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>maybe</span> <span class='hs-layout'>(</span><span class='hs-conid'>False</span><span class='hs-layout'>,</span><span class='hs-varid'>x</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-conid'>(,)</span> <span class='hs-conid'>True</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>op</span> <span class='hs-varid'>x</span><span class='hs-layout'>)</span>
<a name="line-130"></a>
<a name="line-131"></a>
<a name="line-132"></a><a name="rebracket1"></a><span class='hs-comment'>-- | Add/remove brackets as suggested needBracket at 1-level of depth</span>
<a name="line-133"></a><span class='hs-definition'>rebracket1</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Exp_</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Exp_</span>
<a name="line-134"></a><span class='hs-definition'>rebracket1</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>descendBracket</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>\</span><span class='hs-varid'>x</span> <span class='hs-keyglyph'>-></span> <span class='hs-layout'>(</span><span class='hs-conid'>True</span><span class='hs-layout'>,</span><span class='hs-varid'>x</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-135"></a>
<a name="line-136"></a>
<a name="line-137"></a><a name="appsBracket"></a><span class='hs-comment'>-- a list of application, with any necessary brackets</span>
<a name="line-138"></a><span class='hs-definition'>appsBracket</span> <span class='hs-keyglyph'>::</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'>Exp_</span>
<a name="line-139"></a><span class='hs-definition'>appsBracket</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>foldl1</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>\</span><span class='hs-varid'>x</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>rebracket1</span> <span class='hs-varop'>.</span> <span class='hs-conid'>App</span> <span class='hs-varid'>an</span> <span class='hs-varid'>x</span><span class='hs-layout'>)</span>
</pre></body>
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