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<title>src/Hint/Match.hs</title>
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<pre><a name="line-1"></a><span class='hs-comment'>{-# LANGUAGE PatternGuards, ViewPatterns, RelaxedPolyRec #-}</span>
<a name="line-2"></a>
<a name="line-3"></a><span class='hs-comment'>{-
<a name="line-4"></a>The matching does a fairly simple unification between the two terms, treating
<a name="line-5"></a>any single letter variable on the left as a free variable. After the matching
<a name="line-6"></a>we substitute, transform and check the side conditions. We also "see through"
<a name="line-7"></a>both ($) and (.) functions on the right.
<a name="line-8"></a>
<a name="line-9"></a>TRANSFORM PATTERNS
<a name="line-10"></a>_eval_ - perform deep evaluation, must be used at the top of a RHS
<a name="line-11"></a>_noParen_ - don't bracket this particular item
<a name="line-12"></a>
<a name="line-13"></a>SIDE CONDITIONS
<a name="line-14"></a>(&&), (||), not - boolean connectives
<a name="line-15"></a>isAtom x - does x never need brackets
<a name="line-16"></a>isFoo x - is the root constructor of x a "Foo"
<a name="line-17"></a>notEq x y - are x and y not equal
<a name="line-18"></a>notIn xs ys - are all x variables not in ys expressions
<a name="line-19"></a>notTypeSafe - no semantics, a hint for testing only
<a name="line-20"></a>
<a name="line-21"></a>($) AND (.)
<a name="line-22"></a>We see through ($)/(.) by expanding it if nothing else matches.
<a name="line-23"></a>We also see through (.) by translating rules that have (.) equivalents
<a name="line-24"></a>to separate rules. For example:
<a name="line-25"></a>
<a name="line-26"></a>concat (map f x) ==> concatMap f x
<a name="line-27"></a>-- we spot both these rules can eta reduce with respect to x
<a name="line-28"></a>concat . map f ==> concatMap f
<a name="line-29"></a>-- we use the associativity of (.) to add
<a name="line-30"></a>concat . map f . x ==> concatMap f . x
<a name="line-31"></a>-- currently 36 of 169 rules have (.) equivalents
<a name="line-32"></a>-}</span>
<a name="line-33"></a>
<a name="line-34"></a><span class='hs-keyword'>module</span> <span class='hs-conid'>Hint</span><span class='hs-varop'>.</span><span class='hs-conid'>Match</span><span class='hs-layout'>(</span><span class='hs-varid'>readMatch</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-35"></a>
<a name="line-36"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>List</span>
<a name="line-37"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Maybe</span>
<a name="line-38"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Data</span>
<a name="line-39"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Unsafe</span><span class='hs-varop'>.</span><span class='hs-conid'>Coerce</span>
<a name="line-40"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Settings</span>
<a name="line-41"></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-42"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Control</span><span class='hs-varop'>.</span><span class='hs-conid'>Monad</span>
<a name="line-43"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Control</span><span class='hs-varop'>.</span><span class='hs-conid'>Arrow</span>
<a name="line-44"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Util</span>
<a name="line-45"></a>
<a name="line-46"></a>
<a name="line-47"></a><a name="fmapAn"></a><span class='hs-definition'>fmapAn</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>fmap</span> <span class='hs-layout'>(</span><span class='hs-varid'>const</span> <span class='hs-varid'>an</span><span class='hs-layout'>)</span>
<a name="line-48"></a>
<a name="line-49"></a>
<a name="line-50"></a><span class='hs-comment'>---------------------------------------------------------------------</span>
<a name="line-51"></a><span class='hs-comment'>-- READ THE RULE</span>
<a name="line-52"></a>
<a name="line-53"></a><a name="readMatch"></a><span class='hs-definition'>readMatch</span> <span class='hs-keyglyph'>::</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Setting</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>DeclHint</span>
<a name="line-54"></a><span class='hs-definition'>readMatch</span> <span class='hs-varid'>settings</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>findIdeas</span> <span class='hs-layout'>(</span><span class='hs-varid'>concatMap</span> <span class='hs-varid'>readRule</span> <span class='hs-varid'>settings</span><span class='hs-layout'>)</span>
<a name="line-55"></a>
<a name="line-56"></a>
<a name="line-57"></a><a name="readRule"></a><span class='hs-definition'>readRule</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Setting</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Setting</span><span class='hs-keyglyph'>]</span>
<a name="line-58"></a><span class='hs-definition'>readRule</span> <span class='hs-varid'>m</span><span class='hs-keyglyph'>@</span><span class='hs-conid'>MatchExp</span><span class='hs-layout'>{</span><span class='hs-varid'>lhs</span><span class='hs-keyglyph'>=</span><span class='hs-layout'>(</span><span class='hs-varid'>fmapAn</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>lhs</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span> <span class='hs-varid'>rhs</span><span class='hs-keyglyph'>=</span><span class='hs-layout'>(</span><span class='hs-varid'>fmapAn</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>rhs</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span> <span class='hs-varid'>side</span><span class='hs-keyglyph'>=</span><span class='hs-layout'>(</span><span class='hs-varid'>fmap</span> <span class='hs-varid'>fmapAn</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>side</span><span class='hs-layout'>)</span><span class='hs-layout'>}</span> <span class='hs-keyglyph'>=</span>
<a name="line-59"></a> <span class='hs-layout'>(</span><span class='hs-conop'>:</span><span class='hs-layout'>)</span> <span class='hs-varid'>m</span><span class='hs-layout'>{</span><span class='hs-varid'>lhs</span><span class='hs-keyglyph'>=</span><span class='hs-varid'>lhs</span><span class='hs-layout'>,</span><span class='hs-varid'>side</span><span class='hs-keyglyph'>=</span><span class='hs-varid'>side</span><span class='hs-layout'>,</span><span class='hs-varid'>rhs</span><span class='hs-keyglyph'>=</span><span class='hs-varid'>rhs</span><span class='hs-layout'>}</span> <span class='hs-varop'>$</span> <span class='hs-varid'>fromMaybe</span> <span class='hs-conid'>[]</span> <span class='hs-varop'>$</span> <span class='hs-keyword'>do</span>
<a name="line-60"></a> <span class='hs-layout'>(</span><span class='hs-varid'>l</span><span class='hs-layout'>,</span><span class='hs-varid'>v1</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>dotVersion</span> <span class='hs-varid'>lhs</span>
<a name="line-61"></a> <span class='hs-layout'>(</span><span class='hs-varid'>r</span><span class='hs-layout'>,</span><span class='hs-varid'>v2</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>dotVersion</span> <span class='hs-varid'>rhs</span>
<a name="line-62"></a> <span class='hs-varid'>guard</span> <span class='hs-varop'>$</span> <span class='hs-varid'>v1</span> <span class='hs-varop'>==</span> <span class='hs-varid'>v2</span> <span class='hs-varop'>&&</span> <span class='hs-varid'>l</span> <span class='hs-varop'>/=</span> <span class='hs-conid'>[]</span> <span class='hs-varop'>&&</span> <span class='hs-varid'>r</span> <span class='hs-varop'>/=</span> <span class='hs-conid'>[]</span> <span class='hs-varop'>&&</span> <span class='hs-varid'>v1</span> <span class='hs-varop'>`notElem`</span> <span class='hs-varid'>vars</span> <span class='hs-varid'>side</span>
<a name="line-63"></a> <span class='hs-varid'>return</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>m</span><span class='hs-layout'>{</span><span class='hs-varid'>lhs</span><span class='hs-keyglyph'>=</span><span class='hs-varid'>dotApps</span> <span class='hs-varid'>l</span><span class='hs-layout'>,</span> <span class='hs-varid'>rhs</span><span class='hs-keyglyph'>=</span><span class='hs-varid'>dotApps</span> <span class='hs-varid'>r</span><span class='hs-layout'>,</span> <span class='hs-varid'>side</span><span class='hs-keyglyph'>=</span><span class='hs-varid'>side</span><span class='hs-layout'>}</span>
<a name="line-64"></a> <span class='hs-layout'>,</span><span class='hs-varid'>m</span><span class='hs-layout'>{</span><span class='hs-varid'>lhs</span><span class='hs-keyglyph'>=</span><span class='hs-varid'>dotApps</span> <span class='hs-layout'>(</span><span class='hs-varid'>l</span><span class='hs-varop'>++</span><span class='hs-keyglyph'>[</span><span class='hs-varid'>toNamed</span> <span class='hs-varid'>v1</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span> <span class='hs-varid'>rhs</span><span class='hs-keyglyph'>=</span><span class='hs-varid'>dotApps</span> <span class='hs-layout'>(</span><span class='hs-varid'>r</span><span class='hs-varop'>++</span><span class='hs-keyglyph'>[</span><span class='hs-varid'>toNamed</span> <span class='hs-varid'>v1</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span> <span class='hs-varid'>side</span><span class='hs-keyglyph'>=</span><span class='hs-varid'>side</span><span class='hs-layout'>}</span><span class='hs-keyglyph'>]</span>
<a name="line-65"></a><span class='hs-definition'>readRule</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>[]</span>
<a name="line-66"></a>
<a name="line-67"></a>
<a name="line-68"></a><a name="dotVersion"></a><span class='hs-comment'>-- find a dot version of this rule, return the sequence of app prefixes, and the var</span>
<a name="line-69"></a><span class='hs-definition'>dotVersion</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Exp_</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Maybe</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-layout'>,</span> <span class='hs-conid'>String</span><span class='hs-layout'>)</span>
<a name="line-70"></a><span class='hs-definition'>dotVersion</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'>v</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>isUnifyVar</span> <span class='hs-varid'>v</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Just</span> <span class='hs-layout'>(</span><span class='hs-conid'>[]</span><span class='hs-layout'>,</span> <span class='hs-varid'>v</span><span class='hs-layout'>)</span>
<a name="line-71"></a><span class='hs-definition'>dotVersion</span> <span class='hs-layout'>(</span><span class='hs-varid'>fromApps</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>xs</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>length</span> <span class='hs-varid'>xs</span> <span class='hs-varop'>></span> <span class='hs-num'>1</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>fmap</span> <span class='hs-layout'>(</span><span class='hs-varid'>first</span> <span class='hs-layout'>(</span><span class='hs-varid'>apps</span> <span class='hs-layout'>(</span><span class='hs-varid'>init</span> <span class='hs-varid'>xs</span><span class='hs-layout'>)</span> <span class='hs-conop'>:</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-varop'>$</span> <span class='hs-varid'>dotVersion</span> <span class='hs-layout'>(</span><span class='hs-varid'>fromParen</span> <span class='hs-varop'>$</span> <span class='hs-varid'>last</span> <span class='hs-varid'>xs</span><span class='hs-layout'>)</span>
<a name="line-72"></a><span class='hs-definition'>dotVersion</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Nothing</span>
<a name="line-73"></a>
<a name="line-74"></a>
<a name="line-75"></a><span class='hs-comment'>---------------------------------------------------------------------</span>
<a name="line-76"></a><span class='hs-comment'>-- PERFORM THE MATCHING</span>
<a name="line-77"></a>
<a name="line-78"></a><a name="findIdeas"></a><span class='hs-definition'>findIdeas</span> <span class='hs-keyglyph'>::</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Setting</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Scope</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Module</span> <span class='hs-conid'>S</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Decl_</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-79"></a><span class='hs-definition'>findIdeas</span> <span class='hs-varid'>matches</span> <span class='hs-varid'>s</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>decl</span> <span class='hs-keyglyph'>=</span>
<a name="line-80"></a> <span class='hs-keyglyph'>[</span> <span class='hs-varid'>idea</span> <span class='hs-layout'>(</span><span class='hs-varid'>severityS</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>hintS</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-varid'>x</span> <span class='hs-varid'>y</span>
<a name="line-81"></a> <span class='hs-keyglyph'>|</span> <span class='hs-layout'>(</span><span class='hs-varid'>parent</span><span class='hs-layout'>,</span><span class='hs-varid'>x</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>universeParentExp</span> <span class='hs-varid'>decl</span><span class='hs-layout'>,</span> <span class='hs-varid'>not</span> <span class='hs-varop'>$</span> <span class='hs-varid'>isParen</span> <span class='hs-varid'>x</span><span class='hs-layout'>,</span> <span class='hs-keyword'>let</span> <span class='hs-varid'>x2</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>fmapAn</span> <span class='hs-varid'>x</span>
<a name="line-82"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>matches</span><span class='hs-layout'>,</span> <span class='hs-conid'>Just</span> <span class='hs-varid'>y</span> <span class='hs-keyglyph'><-</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>matchIdea</span> <span class='hs-varid'>s</span> <span class='hs-varid'>decl</span> <span class='hs-varid'>m</span> <span class='hs-varid'>parent</span> <span class='hs-varid'>x2</span><span class='hs-keyglyph'>]</span><span class='hs-keyglyph'>]</span>
<a name="line-83"></a>
<a name="line-84"></a>
<a name="line-85"></a><a name="matchIdea"></a><span class='hs-definition'>matchIdea</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Scope</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Decl_</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Setting</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Maybe</span> <span class='hs-layout'>(</span><span class='hs-conid'>Int</span><span class='hs-layout'>,</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'>Maybe</span> <span class='hs-conid'>Exp_</span>
<a name="line-86"></a><span class='hs-definition'>matchIdea</span> <span class='hs-varid'>s</span> <span class='hs-varid'>decl</span> <span class='hs-conid'>MatchExp</span><span class='hs-layout'>{</span><span class='hs-varid'>lhs</span><span class='hs-keyglyph'>=</span><span class='hs-varid'>lhs</span><span class='hs-layout'>,</span><span class='hs-varid'>rhs</span><span class='hs-keyglyph'>=</span><span class='hs-varid'>rhs</span><span class='hs-layout'>,</span><span class='hs-varid'>side</span><span class='hs-keyglyph'>=</span><span class='hs-varid'>side</span><span class='hs-layout'>,</span><span class='hs-varid'>scope</span><span class='hs-keyglyph'>=</span><span class='hs-varid'>scope</span><span class='hs-layout'>}</span> <span class='hs-varid'>parent</span> <span class='hs-varid'>x</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span>
<a name="line-87"></a> <span class='hs-keyword'>let</span> <span class='hs-varid'>nm</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>nameMatch</span> <span class='hs-varid'>scope</span> <span class='hs-varid'>s</span>
<a name="line-88"></a> <span class='hs-varid'>u</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>unifyExp</span> <span class='hs-varid'>nm</span> <span class='hs-varid'>lhs</span> <span class='hs-varid'>x</span>
<a name="line-89"></a> <span class='hs-varid'>u</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>check</span> <span class='hs-varid'>u</span>
<a name="line-90"></a> <span class='hs-keyword'>let</span> <span class='hs-varid'>res</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>addBracket</span> <span class='hs-varid'>parent</span> <span class='hs-varop'>$</span> <span class='hs-varid'>unqualify</span> <span class='hs-varid'>scope</span> <span class='hs-varid'>s</span> <span class='hs-varid'>u</span> <span class='hs-varop'>$</span> <span class='hs-varid'>performEval</span> <span class='hs-varop'>$</span> <span class='hs-varid'>subst</span> <span class='hs-varid'>u</span> <span class='hs-varid'>rhs</span>
<a name="line-91"></a> <span class='hs-varid'>guard</span> <span class='hs-varop'>$</span> <span class='hs-varid'>checkSide</span> <span class='hs-varid'>side</span> <span class='hs-varop'>$</span> <span class='hs-layout'>(</span><span class='hs-str'>"original"</span><span class='hs-layout'>,</span><span class='hs-varid'>x</span><span class='hs-layout'>)</span> <span class='hs-conop'>:</span> <span class='hs-layout'>(</span><span class='hs-str'>"result"</span><span class='hs-layout'>,</span><span class='hs-varid'>res</span><span class='hs-layout'>)</span> <span class='hs-conop'>:</span> <span class='hs-varid'>u</span>
<a name="line-92"></a> <span class='hs-varid'>guard</span> <span class='hs-varop'>$</span> <span class='hs-varid'>checkDefine</span> <span class='hs-varid'>decl</span> <span class='hs-varid'>parent</span> <span class='hs-varid'>res</span>
<a name="line-93"></a> <span class='hs-varid'>return</span> <span class='hs-varid'>res</span>
<a name="line-94"></a>
<a name="line-95"></a>
<a name="line-96"></a><span class='hs-comment'>---------------------------------------------------------------------</span>
<a name="line-97"></a><span class='hs-comment'>-- UNIFICATION</span>
<a name="line-98"></a>
<a name="line-99"></a><a name="unify"></a><span class='hs-comment'>-- unify a b = c, a[c] = b</span>
<a name="line-100"></a><span class='hs-definition'>unify</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Data</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>NameMatch</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'>Maybe</span> <span class='hs-keyglyph'>[</span><span class='hs-layout'>(</span><span class='hs-conid'>String</span><span class='hs-layout'>,</span><span class='hs-conid'>Exp_</span><span class='hs-layout'>)</span><span class='hs-keyglyph'>]</span>
<a name="line-101"></a><span class='hs-definition'>unify</span> <span class='hs-varid'>nm</span> <span class='hs-varid'>x</span> <span class='hs-varid'>y</span> <span class='hs-keyglyph'>|</span> <span class='hs-conid'>Just</span> <span class='hs-varid'>x</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>cast</span> <span class='hs-varid'>x</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>unifyExp</span> <span class='hs-varid'>nm</span> <span class='hs-varid'>x</span> <span class='hs-layout'>(</span><span class='hs-varid'>unsafeCoerce</span> <span class='hs-varid'>y</span><span class='hs-layout'>)</span>
<a name="line-102"></a> <span class='hs-keyglyph'>|</span> <span class='hs-conid'>Just</span> <span class='hs-varid'>x</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>cast</span> <span class='hs-varid'>x</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>unifyPat</span> <span class='hs-varid'>nm</span> <span class='hs-varid'>x</span> <span class='hs-layout'>(</span><span class='hs-varid'>unsafeCoerce</span> <span class='hs-varid'>y</span><span class='hs-layout'>)</span>
<a name="line-103"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>otherwise</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>unifyDef</span> <span class='hs-varid'>nm</span> <span class='hs-varid'>x</span> <span class='hs-varid'>y</span>
<a name="line-104"></a>
<a name="line-105"></a>
<a name="line-106"></a><a name="unifyDef"></a><span class='hs-definition'>unifyDef</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Data</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>NameMatch</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'>Maybe</span> <span class='hs-keyglyph'>[</span><span class='hs-layout'>(</span><span class='hs-conid'>String</span><span class='hs-layout'>,</span><span class='hs-conid'>Exp_</span><span class='hs-layout'>)</span><span class='hs-keyglyph'>]</span>
<a name="line-107"></a><span class='hs-definition'>unifyDef</span> <span class='hs-varid'>nm</span> <span class='hs-varid'>x</span> <span class='hs-varid'>y</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'>sequence</span> <span class='hs-varop'>=<<</span> <span class='hs-varid'>gzip</span> <span class='hs-layout'>(</span><span class='hs-varid'>unify</span> <span class='hs-varid'>nm</span><span class='hs-layout'>)</span> <span class='hs-varid'>x</span> <span class='hs-varid'>y</span>
<a name="line-108"></a>
<a name="line-109"></a>
<a name="line-110"></a><a name="unifyExp"></a><span class='hs-comment'>-- App/InfixApp are analysed specially for performance reasons</span>
<a name="line-111"></a><span class='hs-definition'>unifyExp</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>NameMatch</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Exp_</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Exp_</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Maybe</span> <span class='hs-keyglyph'>[</span><span class='hs-layout'>(</span><span class='hs-conid'>String</span><span class='hs-layout'>,</span><span class='hs-conid'>Exp_</span><span class='hs-layout'>)</span><span class='hs-keyglyph'>]</span>
<a name="line-112"></a><span class='hs-definition'>unifyExp</span> <span class='hs-varid'>nm</span> <span class='hs-varid'>x</span> <span class='hs-varid'>y</span> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>isParen</span> <span class='hs-varid'>x</span> <span class='hs-varop'>||</span> <span class='hs-varid'>isParen</span> <span class='hs-varid'>y</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>unifyExp</span> <span class='hs-varid'>nm</span> <span class='hs-layout'>(</span><span class='hs-varid'>fromParen</span> <span class='hs-varid'>x</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>fromParen</span> <span class='hs-varid'>y</span><span class='hs-layout'>)</span>
<a name="line-113"></a><span class='hs-definition'>unifyExp</span> <span class='hs-varid'>nm</span> <span class='hs-layout'>(</span><span class='hs-conid'>Var</span> <span class='hs-keyword'>_</span> <span class='hs-layout'>(</span><span class='hs-varid'>fromNamed</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>v</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-varid'>y</span> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>isUnifyVar</span> <span class='hs-varid'>v</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Just</span> <span class='hs-keyglyph'>[</span><span class='hs-layout'>(</span><span class='hs-varid'>v</span><span class='hs-layout'>,</span><span class='hs-varid'>y</span><span class='hs-layout'>)</span><span class='hs-keyglyph'>]</span>
<a name="line-114"></a><span class='hs-definition'>unifyExp</span> <span class='hs-varid'>nm</span> <span class='hs-layout'>(</span><span class='hs-conid'>Var</span> <span class='hs-keyword'>_</span> <span class='hs-layout'>(</span><span class='hs-conid'>Qual</span> <span class='hs-keyword'>_</span> <span class='hs-layout'>(</span><span class='hs-conid'>ModuleName</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>m</span><span class='hs-keyglyph'>]</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-layout'>(</span><span class='hs-conid'>Var</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>y</span><span class='hs-layout'>)</span>
<a name="line-115"></a> <span class='hs-keyglyph'>|</span> <span class='hs-conid'>Qual</span> <span class='hs-keyword'>_</span> <span class='hs-layout'>(</span><span class='hs-conid'>ModuleName</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>m2</span><span class='hs-layout'>)</span> <span class='hs-varid'>y</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>y</span><span class='hs-layout'>,</span> <span class='hs-varid'>y</span> <span class='hs-varop'>==</span> <span class='hs-varid'>x</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Just</span> <span class='hs-keyglyph'>[</span><span class='hs-layout'>(</span><span class='hs-keyglyph'>[</span><span class='hs-varid'>m</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>,</span> <span class='hs-conid'>Var</span> <span class='hs-varid'>an</span> <span class='hs-varop'>$</span> <span class='hs-conid'>UnQual</span> <span class='hs-varid'>an</span> <span class='hs-varop'>$</span> <span class='hs-conid'>Ident</span> <span class='hs-varid'>an</span> <span class='hs-varid'>m2</span><span class='hs-layout'>)</span><span class='hs-keyglyph'>]</span>
<a name="line-116"></a> <span class='hs-keyglyph'>|</span> <span class='hs-conid'>UnQual</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>y</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>y</span><span class='hs-layout'>,</span> <span class='hs-varid'>y</span> <span class='hs-varop'>==</span> <span class='hs-varid'>x</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Just</span> <span class='hs-keyglyph'>[</span><span class='hs-layout'>(</span><span class='hs-keyglyph'>[</span><span class='hs-varid'>m</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>,</span> <span class='hs-conid'>Var</span> <span class='hs-varid'>an</span> <span class='hs-varop'>$</span> <span class='hs-conid'>UnQual</span> <span class='hs-varid'>an</span> <span class='hs-varop'>$</span> <span class='hs-conid'>Ident</span> <span class='hs-varid'>an</span> <span class='hs-str'>""</span><span class='hs-layout'>)</span><span class='hs-keyglyph'>]</span>
<a name="line-117"></a><span class='hs-definition'>unifyExp</span> <span class='hs-varid'>nm</span> <span class='hs-layout'>(</span><span class='hs-conid'>Var</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>x</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-conid'>Var</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'>nm</span> <span class='hs-varid'>x</span> <span class='hs-varid'>y</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Just</span> <span class='hs-conid'>[]</span>
<a name="line-118"></a><span class='hs-definition'>unifyExp</span> <span class='hs-varid'>nm</span> <span class='hs-varid'>x</span><span class='hs-keyglyph'>@</span><span class='hs-layout'>(</span><span class='hs-conid'>App</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>x1</span> <span class='hs-varid'>x2</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-conid'>App</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>y1</span> <span class='hs-varid'>y2</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span>
<a name="line-119"></a> <span class='hs-varid'>liftM2</span> <span class='hs-layout'>(</span><span class='hs-varop'>++</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>unifyExp</span> <span class='hs-varid'>nm</span> <span class='hs-varid'>x1</span> <span class='hs-varid'>y1</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>unifyExp</span> <span class='hs-varid'>nm</span> <span class='hs-varid'>x2</span> <span class='hs-varid'>y2</span><span class='hs-layout'>)</span> <span class='hs-varop'>`mplus`</span>
<a name="line-120"></a> <span class='hs-layout'>(</span><span class='hs-keyword'>do</span> <span class='hs-conid'>InfixApp</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>y11</span> <span class='hs-varid'>dot</span> <span class='hs-varid'>y12</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>return</span> <span class='hs-varop'>$</span> <span class='hs-varid'>fromParen</span> <span class='hs-varid'>y1</span><span class='hs-layout'>;</span> <span class='hs-varid'>guard</span> <span class='hs-varop'>$</span> <span class='hs-varid'>isDot</span> <span class='hs-varid'>dot</span><span class='hs-layout'>;</span> <span class='hs-varid'>unifyExp</span> <span class='hs-varid'>nm</span> <span class='hs-varid'>x</span> <span class='hs-layout'>(</span><span class='hs-conid'>App</span> <span class='hs-varid'>an</span> <span class='hs-varid'>y11</span> <span class='hs-layout'>(</span><span class='hs-conid'>App</span> <span class='hs-varid'>an</span> <span class='hs-varid'>y12</span> <span class='hs-varid'>y2</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-121"></a><span class='hs-definition'>unifyExp</span> <span class='hs-varid'>nm</span> <span class='hs-varid'>x</span> <span class='hs-layout'>(</span><span class='hs-conid'>InfixApp</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>lhs2</span> <span class='hs-varid'>op2</span> <span class='hs-varid'>rhs2</span><span class='hs-layout'>)</span>
<a name="line-122"></a> <span class='hs-keyglyph'>|</span> <span class='hs-conid'>InfixApp</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>lhs1</span> <span class='hs-varid'>op1</span> <span class='hs-varid'>rhs1</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>x</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>guard</span> <span class='hs-layout'>(</span><span class='hs-varid'>op1</span> <span class='hs-varop'>==</span> <span class='hs-varid'>op2</span><span class='hs-layout'>)</span> <span class='hs-varop'>>></span> <span class='hs-varid'>liftM2</span> <span class='hs-layout'>(</span><span class='hs-varop'>++</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>unifyExp</span> <span class='hs-varid'>nm</span> <span class='hs-varid'>lhs1</span> <span class='hs-varid'>lhs2</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>unifyExp</span> <span class='hs-varid'>nm</span> <span class='hs-varid'>rhs1</span> <span class='hs-varid'>rhs2</span><span class='hs-layout'>)</span>
<a name="line-123"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>isDol</span> <span class='hs-varid'>op2</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>unifyExp</span> <span class='hs-varid'>nm</span> <span class='hs-varid'>x</span> <span class='hs-varop'>$</span> <span class='hs-conid'>App</span> <span class='hs-varid'>an</span> <span class='hs-varid'>lhs2</span> <span class='hs-varid'>rhs2</span>
<a name="line-124"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>otherwise</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>unifyExp</span> <span class='hs-varid'>nm</span> <span class='hs-varid'>x</span> <span class='hs-varop'>$</span> <span class='hs-conid'>App</span> <span class='hs-varid'>an</span> <span class='hs-layout'>(</span><span class='hs-conid'>App</span> <span class='hs-varid'>an</span> <span class='hs-layout'>(</span><span class='hs-varid'>opExp</span> <span class='hs-varid'>op2</span><span class='hs-layout'>)</span> <span class='hs-varid'>lhs2</span><span class='hs-layout'>)</span> <span class='hs-varid'>rhs2</span>
<a name="line-125"></a><span class='hs-definition'>unifyExp</span> <span class='hs-varid'>nm</span> <span class='hs-varid'>x</span> <span class='hs-varid'>y</span> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>isOther</span> <span class='hs-varid'>x</span><span class='hs-layout'>,</span> <span class='hs-varid'>isOther</span> <span class='hs-varid'>y</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>unifyDef</span> <span class='hs-varid'>nm</span> <span class='hs-varid'>x</span> <span class='hs-varid'>y</span>
<a name="line-126"></a><span class='hs-definition'>unifyExp</span> <span class='hs-varid'>nm</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Nothing</span>
<a name="line-127"></a>
<a name="line-128"></a>
<a name="line-129"></a><a name="unifyPat"></a><span class='hs-definition'>unifyPat</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>NameMatch</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Pat_</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Pat_</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Maybe</span> <span class='hs-keyglyph'>[</span><span class='hs-layout'>(</span><span class='hs-conid'>String</span><span class='hs-layout'>,</span><span class='hs-conid'>Exp_</span><span class='hs-layout'>)</span><span class='hs-keyglyph'>]</span>
<a name="line-130"></a><span class='hs-definition'>unifyPat</span> <span class='hs-varid'>nm</span> <span class='hs-layout'>(</span><span class='hs-conid'>PVar</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>x</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-conid'>PVar</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-conid'>Just</span> <span class='hs-keyglyph'>[</span><span class='hs-layout'>(</span><span class='hs-varid'>fromNamed</span> <span class='hs-varid'>x</span><span class='hs-layout'>,</span> <span class='hs-varid'>toNamed</span> <span class='hs-varop'>$</span> <span class='hs-varid'>fromNamed</span> <span class='hs-varid'>y</span><span class='hs-layout'>)</span><span class='hs-keyglyph'>]</span>
<a name="line-131"></a><span class='hs-definition'>unifyPat</span> <span class='hs-varid'>nm</span> <span class='hs-conid'>PWildCard</span><span class='hs-layout'>{</span><span class='hs-layout'>}</span> <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'>Just</span> <span class='hs-conid'>[]</span>
<a name="line-132"></a><span class='hs-definition'>unifyPat</span> <span class='hs-varid'>nm</span> <span class='hs-varid'>x</span> <span class='hs-varid'>y</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>unifyDef</span> <span class='hs-varid'>nm</span> <span class='hs-varid'>x</span> <span class='hs-varid'>y</span>
<a name="line-133"></a>
<a name="line-134"></a>
<a name="line-135"></a><a name="isOther"></a><span class='hs-comment'>-- types that are not already handled in unify</span>
<a name="line-136"></a><span class='hs-comment'>{-# INLINE isOther #-}</span>
<a name="line-137"></a><span class='hs-definition'>isOther</span> <span class='hs-conid'>Var</span><span class='hs-layout'>{</span><span class='hs-layout'>}</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>False</span>
<a name="line-138"></a><span class='hs-definition'>isOther</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-conid'>False</span>
<a name="line-139"></a><span class='hs-definition'>isOther</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-conid'>False</span>
<a name="line-140"></a><span class='hs-definition'>isOther</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>True</span>
<a name="line-141"></a>
<a name="line-142"></a>
<a name="line-143"></a><span class='hs-comment'>---------------------------------------------------------------------</span>
<a name="line-144"></a><span class='hs-comment'>-- SUBSTITUTION UTILITIES</span>
<a name="line-145"></a>
<a name="line-146"></a><a name="check"></a><span class='hs-comment'>-- check the unification is valid</span>
<a name="line-147"></a><span class='hs-definition'>check</span> <span class='hs-keyglyph'>::</span> <span class='hs-keyglyph'>[</span><span class='hs-layout'>(</span><span class='hs-conid'>String</span><span class='hs-layout'>,</span><span class='hs-conid'>Exp_</span><span class='hs-layout'>)</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Maybe</span> <span class='hs-keyglyph'>[</span><span class='hs-layout'>(</span><span class='hs-conid'>String</span><span class='hs-layout'>,</span><span class='hs-conid'>Exp_</span><span class='hs-layout'>)</span><span class='hs-keyglyph'>]</span>
<a name="line-148"></a><span class='hs-definition'>check</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>mapM</span> <span class='hs-varid'>f</span> <span class='hs-varop'>.</span> <span class='hs-varid'>groupSortFst</span>
<a name="line-149"></a> <span class='hs-keyword'>where</span> <span class='hs-varid'>f</span> <span class='hs-layout'>(</span><span class='hs-varid'>x</span><span class='hs-layout'>,</span><span class='hs-varid'>ys</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>if</span> <span class='hs-varid'>length</span> <span class='hs-layout'>(</span><span class='hs-varid'>nub</span> <span class='hs-varid'>ys</span><span class='hs-layout'>)</span> <span class='hs-varop'>==</span> <span class='hs-num'>1</span> <span class='hs-keyword'>then</span> <span class='hs-conid'>Just</span> <span class='hs-layout'>(</span><span class='hs-varid'>x</span><span class='hs-layout'>,</span><span class='hs-varid'>head</span> <span class='hs-varid'>ys</span><span class='hs-layout'>)</span> <span class='hs-keyword'>else</span> <span class='hs-conid'>Nothing</span>
<a name="line-150"></a>
<a name="line-151"></a>
<a name="line-152"></a><a name="subst"></a><span class='hs-comment'>-- perform a substitution</span>
<a name="line-153"></a><span class='hs-definition'>subst</span> <span class='hs-keyglyph'>::</span> <span class='hs-keyglyph'>[</span><span class='hs-layout'>(</span><span class='hs-conid'>String</span><span class='hs-layout'>,</span><span class='hs-conid'>Exp_</span><span class='hs-layout'>)</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-conid'>Exp_</span>
<a name="line-154"></a><span class='hs-definition'>subst</span> <span class='hs-varid'>bind</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>transform</span> <span class='hs-varid'>g</span> <span class='hs-varop'>.</span> <span class='hs-varid'>transformBracket</span> <span class='hs-varid'>f</span>
<a name="line-155"></a> <span class='hs-keyword'>where</span>
<a name="line-156"></a> <span class='hs-varid'>f</span> <span class='hs-layout'>(</span><span class='hs-conid'>Var</span> <span class='hs-keyword'>_</span> <span class='hs-layout'>(</span><span class='hs-varid'>fromNamed</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>x</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>isUnifyVar</span> <span class='hs-varid'>x</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>lookup</span> <span class='hs-varid'>x</span> <span class='hs-varid'>bind</span>
<a name="line-157"></a> <span class='hs-varid'>f</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Nothing</span>
<a name="line-158"></a>
<a name="line-159"></a> <span class='hs-varid'>g</span> <span class='hs-layout'>(</span><span class='hs-conid'>App</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>np</span> <span class='hs-varid'>x</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>np</span> <span class='hs-varop'>~=</span> <span class='hs-str'>"_noParen_"</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>fromParen</span> <span class='hs-varid'>x</span>
<a name="line-160"></a> <span class='hs-varid'>g</span> <span class='hs-varid'>x</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>x</span>
<a name="line-161"></a>
<a name="line-162"></a>
<a name="line-163"></a><span class='hs-comment'>---------------------------------------------------------------------</span>
<a name="line-164"></a><span class='hs-comment'>-- SIDE CONDITIONS</span>
<a name="line-165"></a>
<a name="line-166"></a><a name="checkSide"></a><span class='hs-definition'>checkSide</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Maybe</span> <span class='hs-conid'>Exp_</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyglyph'>[</span><span class='hs-layout'>(</span><span class='hs-conid'>String</span><span class='hs-layout'>,</span><span class='hs-conid'>Exp_</span><span class='hs-layout'>)</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Bool</span>
<a name="line-167"></a><span class='hs-definition'>checkSide</span> <span class='hs-varid'>x</span> <span class='hs-varid'>bind</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>maybe</span> <span class='hs-conid'>True</span> <span class='hs-varid'>f</span> <span class='hs-varid'>x</span>
<a name="line-168"></a> <span class='hs-keyword'>where</span>
<a name="line-169"></a> <span class='hs-varid'>f</span> <span class='hs-layout'>(</span><span class='hs-conid'>InfixApp</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>x</span> <span class='hs-varid'>op</span> <span class='hs-varid'>y</span><span class='hs-layout'>)</span>
<a name="line-170"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>opExp</span> <span class='hs-varid'>op</span> <span class='hs-varop'>~=</span> <span class='hs-str'>"&&"</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>f</span> <span class='hs-varid'>x</span> <span class='hs-varop'>&&</span> <span class='hs-varid'>f</span> <span class='hs-varid'>y</span>
<a name="line-171"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>opExp</span> <span class='hs-varid'>op</span> <span class='hs-varop'>~=</span> <span class='hs-str'>"||"</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>f</span> <span class='hs-varid'>x</span> <span class='hs-varop'>||</span> <span class='hs-varid'>f</span> <span class='hs-varid'>y</span>
<a name="line-172"></a> <span class='hs-varid'>f</span> <span class='hs-layout'>(</span><span class='hs-conid'>App</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>x</span> <span class='hs-varid'>y</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>x</span> <span class='hs-varop'>~=</span> <span class='hs-str'>"not"</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>not</span> <span class='hs-varop'>$</span> <span class='hs-varid'>f</span> <span class='hs-varid'>y</span>
<a name="line-173"></a> <span class='hs-varid'>f</span> <span class='hs-layout'>(</span><span class='hs-conid'>Paren</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>x</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>f</span> <span class='hs-varid'>x</span>
<a name="line-174"></a>
<a name="line-175"></a> <span class='hs-varid'>f</span> <span class='hs-layout'>(</span><span class='hs-conid'>App</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>cond</span> <span class='hs-layout'>(</span><span class='hs-varid'>sub</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>y</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-176"></a> <span class='hs-keyglyph'>|</span> <span class='hs-chr'>'i'</span><span class='hs-conop'>:</span><span class='hs-chr'>'s'</span><span class='hs-conop'>:</span><span class='hs-varid'>typ</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>fromNamed</span> <span class='hs-varid'>cond</span>
<a name="line-177"></a> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>if</span> <span class='hs-varid'>typ</span> <span class='hs-varop'>==</span> <span class='hs-str'>"Atom"</span> <span class='hs-keyword'>then</span> <span class='hs-varid'>isAtom</span> <span class='hs-varid'>y</span> <span class='hs-keyword'>else</span> <span class='hs-varid'>head</span> <span class='hs-layout'>(</span><span class='hs-varid'>words</span> <span class='hs-varop'>$</span> <span class='hs-varid'>show</span> <span class='hs-varid'>y</span><span class='hs-layout'>)</span> <span class='hs-varop'>==</span> <span class='hs-varid'>typ</span>
<a name="line-178"></a> <span class='hs-varid'>f</span> <span class='hs-layout'>(</span><span class='hs-conid'>App</span> <span class='hs-keyword'>_</span> <span class='hs-layout'>(</span><span class='hs-conid'>App</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>cond</span> <span class='hs-layout'>(</span><span class='hs-varid'>sub</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>x</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>sub</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>y</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-179"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>cond</span> <span class='hs-varop'>~=</span> <span class='hs-str'>"notIn"</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>and</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>x</span> <span class='hs-varop'>`notElem`</span> <span class='hs-varid'>universe</span> <span class='hs-varid'>y</span> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>x</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>list</span> <span class='hs-varid'>x</span><span class='hs-layout'>,</span> <span class='hs-varid'>y</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>list</span> <span class='hs-varid'>y</span><span class='hs-keyglyph'>]</span>
<a name="line-180"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>cond</span> <span class='hs-varop'>~=</span> <span class='hs-str'>"notEq"</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>x</span> <span class='hs-varop'>/=</span> <span class='hs-varid'>y</span>
<a name="line-181"></a> <span class='hs-varid'>f</span> <span class='hs-varid'>x</span> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>x</span> <span class='hs-varop'>~=</span> <span class='hs-str'>"notTypeSafe"</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>True</span>
<a name="line-182"></a> <span class='hs-varid'>f</span> <span class='hs-varid'>x</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>error</span> <span class='hs-varop'>$</span> <span class='hs-str'>"Hint.Match.checkSide, unknown side condition: "</span> <span class='hs-varop'>++</span> <span class='hs-varid'>prettyPrint</span> <span class='hs-varid'>x</span>
<a name="line-183"></a>
<a name="line-184"></a> <span class='hs-varid'>list</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><span class='hs-keyglyph'>]</span>
<a name="line-185"></a> <span class='hs-varid'>list</span> <span class='hs-layout'>(</span><span class='hs-conid'>List</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>xs</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>xs</span>
<a name="line-186"></a> <span class='hs-varid'>list</span> <span class='hs-varid'>x</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>x</span><span class='hs-keyglyph'>]</span>
<a name="line-187"></a>
<a name="line-188"></a> <span class='hs-varid'>sub</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-189"></a> <span class='hs-varid'>sub</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>transform</span> <span class='hs-varid'>f</span>
<a name="line-190"></a> <span class='hs-keyword'>where</span> <span class='hs-varid'>f</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'>x</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>|</span> <span class='hs-conid'>Just</span> <span class='hs-varid'>y</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>lookup</span> <span class='hs-varid'>x</span> <span class='hs-varid'>bind</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>y</span>
<a name="line-191"></a> <span class='hs-varid'>f</span> <span class='hs-varid'>x</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>x</span>
<a name="line-192"></a>
<a name="line-193"></a>
<a name="line-194"></a><a name="checkDefine"></a><span class='hs-comment'>-- does the result look very much like the declaration</span>
<a name="line-195"></a><span class='hs-definition'>checkDefine</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Decl_</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Maybe</span> <span class='hs-layout'>(</span><span class='hs-conid'>Int</span><span class='hs-layout'>,</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'>Bool</span>
<a name="line-196"></a><span class='hs-definition'>checkDefine</span> <span class='hs-varid'>x</span> <span class='hs-conid'>Nothing</span> <span class='hs-varid'>y</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>fromNamed</span> <span class='hs-varid'>x</span> <span class='hs-varop'>/=</span> <span class='hs-varid'>fromNamed</span> <span class='hs-layout'>(</span><span class='hs-varid'>transformBi</span> <span class='hs-varid'>unqual</span> <span class='hs-varop'>$</span> <span class='hs-varid'>head</span> <span class='hs-varop'>$</span> <span class='hs-varid'>fromApps</span> <span class='hs-varid'>y</span><span class='hs-layout'>)</span>
<a name="line-197"></a><span class='hs-definition'>checkDefine</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>True</span>
<a name="line-198"></a>
<a name="line-199"></a>
<a name="line-200"></a><span class='hs-comment'>---------------------------------------------------------------------</span>
<a name="line-201"></a><span class='hs-comment'>-- TRANSFORMATION</span>
<a name="line-202"></a>
<a name="line-203"></a><a name="performEval"></a><span class='hs-comment'>-- if it has _eval_ do evaluation on it</span>
<a name="line-204"></a><span class='hs-definition'>performEval</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-205"></a><span class='hs-definition'>performEval</span> <span class='hs-layout'>(</span><span class='hs-conid'>App</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>e</span> <span class='hs-varid'>x</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>e</span> <span class='hs-varop'>~=</span> <span class='hs-str'>"_eval_"</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>evaluate</span> <span class='hs-varid'>x</span>
<a name="line-206"></a><span class='hs-definition'>performEval</span> <span class='hs-varid'>x</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>x</span>
<a name="line-207"></a>
<a name="line-208"></a>
<a name="line-209"></a><a name="unqualify"></a><span class='hs-comment'>-- contract Data.List.foo ==> foo, if Data.List is loaded</span>
<a name="line-210"></a><span class='hs-comment'>-- change X.foo => Module.foo, where X is looked up in the subst</span>
<a name="line-211"></a><span class='hs-definition'>unqualify</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Scope</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Scope</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyglyph'>[</span><span class='hs-layout'>(</span><span class='hs-conid'>String</span><span class='hs-layout'>,</span><span class='hs-conid'>Exp_</span><span class='hs-layout'>)</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-conid'>Exp_</span>
<a name="line-212"></a><span class='hs-definition'>unqualify</span> <span class='hs-varid'>from</span> <span class='hs-varid'>to</span> <span class='hs-varid'>subs</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>transformBi</span> <span class='hs-varid'>f</span>
<a name="line-213"></a> <span class='hs-keyword'>where</span>
<a name="line-214"></a> <span class='hs-varid'>f</span> <span class='hs-layout'>(</span><span class='hs-conid'>Qual</span> <span class='hs-keyword'>_</span> <span class='hs-layout'>(</span><span class='hs-conid'>ModuleName</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>m</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>)</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'>y</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>fmap</span> <span class='hs-varid'>fromNamed</span> <span class='hs-varop'>$</span> <span class='hs-varid'>lookup</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>m</span><span class='hs-keyglyph'>]</span> <span class='hs-varid'>subs</span>
<a name="line-215"></a> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>if</span> <span class='hs-varid'>null</span> <span class='hs-varid'>y</span> <span class='hs-keyword'>then</span> <span class='hs-conid'>UnQual</span> <span class='hs-varid'>an</span> <span class='hs-varid'>x</span> <span class='hs-keyword'>else</span> <span class='hs-conid'>Qual</span> <span class='hs-varid'>an</span> <span class='hs-layout'>(</span><span class='hs-conid'>ModuleName</span> <span class='hs-varid'>an</span> <span class='hs-varid'>y</span><span class='hs-layout'>)</span> <span class='hs-varid'>x</span>
<a name="line-216"></a> <span class='hs-varid'>f</span> <span class='hs-varid'>x</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>nameQualify</span> <span class='hs-varid'>from</span> <span class='hs-varid'>to</span> <span class='hs-varid'>x</span>
<a name="line-217"></a>
<a name="line-218"></a>
<a name="line-219"></a><a name="addBracket"></a><span class='hs-definition'>addBracket</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Maybe</span> <span class='hs-layout'>(</span><span class='hs-conid'>Int</span><span class='hs-layout'>,</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-220"></a><span class='hs-definition'>addBracket</span> <span class='hs-layout'>(</span><span class='hs-conid'>Just</span> <span class='hs-layout'>(</span><span class='hs-varid'>i</span><span class='hs-layout'>,</span><span class='hs-varid'>p</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-varid'>c</span> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>needBracket</span> <span class='hs-varid'>i</span> <span class='hs-varid'>p</span> <span class='hs-varid'>c</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Paren</span> <span class='hs-varid'>an</span> <span class='hs-varid'>c</span>
<a name="line-221"></a><span class='hs-definition'>addBracket</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>x</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>x</span>
</pre></body>
</html>
