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<pre><a name="line-1"></a><span class='hs-comment'>-----------------------------------------------------------------------------</span>
<a name="line-2"></a><span class='hs-comment'>-- |</span>
<a name="line-3"></a><span class='hs-comment'>-- Module : ParseLib</span>
<a name="line-4"></a><span class='hs-comment'>-- Copyright : ...</span>
<a name="line-5"></a><span class='hs-comment'>-- Copyright : Graham Hutton (University of Nottingham), Erik Meijer (University of Utrecht)</span>
<a name="line-6"></a><span class='hs-comment'>-- </span>
<a name="line-7"></a><span class='hs-comment'>-- Maintainer : Malcolm Wallace <Malcolm.Wallace@cs.york.ac.uk></span>
<a name="line-8"></a><span class='hs-comment'>-- Stability : Stable</span>
<a name="line-9"></a><span class='hs-comment'>-- Portability : All</span>
<a name="line-10"></a><span class='hs-comment'>--</span>
<a name="line-11"></a><span class='hs-comment'>-- A LIBRARY OF MONADIC PARSER COMBINATORS</span>
<a name="line-12"></a><span class='hs-comment'>-- </span>
<a name="line-13"></a><span class='hs-comment'>-- 29th July 1996</span>
<a name="line-14"></a><span class='hs-comment'>-- </span>
<a name="line-15"></a><span class='hs-comment'>-- Graham Hutton Erik Meijer</span>
<a name="line-16"></a><span class='hs-comment'>-- University of Nottingham University of Utrecht</span>
<a name="line-17"></a><span class='hs-comment'>-- </span>
<a name="line-18"></a><span class='hs-comment'>-- This Haskell script defines a library of parser combinators, and is</span>
<a name="line-19"></a><span class='hs-comment'>-- taken from sections 1-6 of our article "Monadic Parser Combinators".</span>
<a name="line-20"></a><span class='hs-comment'>-- Some changes to the library have been made in the move from Gofer</span>
<a name="line-21"></a><span class='hs-comment'>-- to Haskell:</span>
<a name="line-22"></a><span class='hs-comment'>-- </span>
<a name="line-23"></a><span class='hs-comment'>-- * Do notation is used in place of monad comprehension notation;</span>
<a name="line-24"></a><span class='hs-comment'>-- </span>
<a name="line-25"></a><span class='hs-comment'>-- * The parser datatype is defined using "newtype", to avoid the overhead</span>
<a name="line-26"></a><span class='hs-comment'>-- of tagging and untagging parsers with the P constructor.</span>
<a name="line-27"></a><span class='hs-comment'>-----------------------------------------------------------------------------</span>
<a name="line-28"></a>
<a name="line-29"></a>
<a name="line-30"></a><span class='hs-keyword'>module</span> <span class='hs-conid'>Text</span><span class='hs-varop'>.</span><span class='hs-conid'>ParserCombinators</span><span class='hs-varop'>.</span><span class='hs-conid'>HuttonMeijer</span>
<a name="line-31"></a> <span class='hs-layout'>(</span><span class='hs-conid'>Parser</span><span class='hs-layout'>(</span><span class='hs-keyglyph'>..</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span> <span class='hs-varid'>item</span><span class='hs-layout'>,</span> <span class='hs-varid'>first</span><span class='hs-layout'>,</span> <span class='hs-varid'>papply</span><span class='hs-layout'>,</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'>sat</span><span class='hs-layout'>,</span> <span class='hs-comment'>{-tok,-}</span> <span class='hs-varid'>many</span><span class='hs-layout'>,</span> <span class='hs-varid'>many1</span><span class='hs-layout'>,</span>
<a name="line-32"></a> <span class='hs-varid'>sepby</span><span class='hs-layout'>,</span> <span class='hs-varid'>sepby1</span><span class='hs-layout'>,</span> <span class='hs-varid'>chainl</span><span class='hs-layout'>,</span>
<a name="line-33"></a> <span class='hs-varid'>chainl1</span><span class='hs-layout'>,</span> <span class='hs-varid'>chainr</span><span class='hs-layout'>,</span> <span class='hs-varid'>chainr1</span><span class='hs-layout'>,</span> <span class='hs-varid'>ops</span><span class='hs-layout'>,</span> <span class='hs-varid'>bracket</span><span class='hs-layout'>,</span> <span class='hs-varid'>char</span><span class='hs-layout'>,</span> <span class='hs-varid'>digit</span><span class='hs-layout'>,</span> <span class='hs-varid'>lower</span><span class='hs-layout'>,</span> <span class='hs-varid'>upper</span><span class='hs-layout'>,</span>
<a name="line-34"></a> <span class='hs-varid'>letter</span><span class='hs-layout'>,</span> <span class='hs-varid'>alphanum</span><span class='hs-layout'>,</span> <span class='hs-varid'>string</span><span class='hs-layout'>,</span> <span class='hs-varid'>ident</span><span class='hs-layout'>,</span> <span class='hs-varid'>nat</span><span class='hs-layout'>,</span> <span class='hs-varid'>int</span><span class='hs-layout'>,</span> <span class='hs-varid'>spaces</span><span class='hs-layout'>,</span> <span class='hs-varid'>comment</span><span class='hs-layout'>,</span> <span class='hs-varid'>junk</span><span class='hs-layout'>,</span>
<a name="line-35"></a> <span class='hs-varid'>skip</span><span class='hs-layout'>,</span> <span class='hs-varid'>token</span><span class='hs-layout'>,</span> <span class='hs-varid'>natural</span><span class='hs-layout'>,</span> <span class='hs-varid'>integer</span><span class='hs-layout'>,</span> <span class='hs-varid'>symbol</span><span class='hs-layout'>,</span> <span class='hs-varid'>identifier</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-36"></a>
<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'>Char</span>
<a name="line-38"></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-39"></a>
<a name="line-40"></a><span class='hs-keyword'>infixr</span> <span class='hs-num'>5</span> <span class='hs-varop'>+++</span>
<a name="line-41"></a>
<a name="line-42"></a><a name="Token"></a><span class='hs-keyword'>type</span> <span class='hs-conid'>Token</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Char</span>
<a name="line-43"></a>
<a name="line-44"></a><span class='hs-comment'>---------------------------------------------------------</span>
<a name="line-45"></a><span class='hs-comment'>-- | The parser monad</span>
<a name="line-46"></a>
<a name="line-47"></a><a name="Parser"></a><span class='hs-keyword'>newtype</span> <span class='hs-conid'>Parser</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>P</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>[</span><span class='hs-conid'>Token</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyglyph'>[</span><span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span><span class='hs-keyglyph'>[</span><span class='hs-conid'>Token</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>)</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>)</span>
<a name="line-48"></a>
<a name="line-49"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>Functor</span> <span class='hs-conid'>Parser</span> <span class='hs-keyword'>where</span>
<a name="line-50"></a> <span class='hs-comment'>-- map :: (a -> b) -> (Parser a -> Parser b)</span>
<a name="line-51"></a> <span class='hs-varid'>fmap</span> <span class='hs-varid'>f</span> <span class='hs-layout'>(</span><span class='hs-conid'>P</span> <span class='hs-varid'>p</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>P</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>\</span><span class='hs-varid'>inp</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyglyph'>[</span><span class='hs-layout'>(</span><span class='hs-varid'>f</span> <span class='hs-varid'>v</span><span class='hs-layout'>,</span> <span class='hs-varid'>out</span><span class='hs-layout'>)</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'>out</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>p</span> <span class='hs-varid'>inp</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>)</span>
<a name="line-52"></a>
<a name="line-53"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>Monad</span> <span class='hs-conid'>Parser</span> <span class='hs-keyword'>where</span>
<a name="line-54"></a> <span class='hs-comment'>-- return :: a -> Parser a</span>
<a name="line-55"></a> <span class='hs-varid'>return</span> <span class='hs-varid'>v</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>P</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>\</span><span class='hs-varid'>inp</span> <span class='hs-keyglyph'>-></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'>inp</span><span class='hs-layout'>)</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>)</span>
<a name="line-56"></a>
<a name="line-57"></a> <span class='hs-comment'>-- >>= :: Parser a -> (a -> Parser b) -> Parser b</span>
<a name="line-58"></a> <span class='hs-layout'>(</span><span class='hs-conid'>P</span> <span class='hs-varid'>p</span><span class='hs-layout'>)</span> <span class='hs-varop'>>>=</span> <span class='hs-varid'>f</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>P</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>\</span><span class='hs-varid'>inp</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>concat</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>papply</span> <span class='hs-layout'>(</span><span class='hs-varid'>f</span> <span class='hs-varid'>v</span><span class='hs-layout'>)</span> <span class='hs-varid'>out</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'>out</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>p</span> <span class='hs-varid'>inp</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>)</span>
<a name="line-59"></a>
<a name="line-60"></a> <span class='hs-comment'>-- fail :: String -> Parser a</span>
<a name="line-61"></a> <span class='hs-varid'>fail</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>P</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>\</span><span class='hs-keyword'>_</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>[]</span><span class='hs-layout'>)</span>
<a name="line-62"></a>
<a name="line-63"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>MonadPlus</span> <span class='hs-conid'>Parser</span> <span class='hs-keyword'>where</span>
<a name="line-64"></a> <span class='hs-comment'>-- mzero :: Parser a</span>
<a name="line-65"></a> <span class='hs-varid'>mzero</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>P</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>\</span><span class='hs-keyword'>_</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>[]</span><span class='hs-layout'>)</span>
<a name="line-66"></a>
<a name="line-67"></a> <span class='hs-comment'>-- mplus :: Parser a -> Parser a -> Parser a</span>
<a name="line-68"></a> <span class='hs-layout'>(</span><span class='hs-conid'>P</span> <span class='hs-varid'>p</span><span class='hs-layout'>)</span> <span class='hs-varop'>`mplus`</span> <span class='hs-layout'>(</span><span class='hs-conid'>P</span> <span class='hs-varid'>q</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>P</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>\</span><span class='hs-varid'>inp</span> <span class='hs-keyglyph'>-></span> <span class='hs-layout'>(</span><span class='hs-varid'>p</span> <span class='hs-varid'>inp</span> <span class='hs-varop'>++</span> <span class='hs-varid'>q</span> <span class='hs-varid'>inp</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-69"></a>
<a name="line-70"></a><span class='hs-comment'>-- ------------------------------------------------------------</span>
<a name="line-71"></a><span class='hs-comment'>-- * Other primitive parser combinators</span>
<a name="line-72"></a><span class='hs-comment'>-- ------------------------------------------------------------</span>
<a name="line-73"></a>
<a name="line-74"></a><a name="item"></a><span class='hs-definition'>item</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Parser</span> <span class='hs-conid'>Token</span>
<a name="line-75"></a><span class='hs-definition'>item</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>P</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>\</span><span class='hs-varid'>inp</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyword'>case</span> <span class='hs-varid'>inp</span> <span class='hs-keyword'>of</span>
<a name="line-76"></a> <span class='hs-conid'>[]</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>[]</span>
<a name="line-77"></a> <span class='hs-layout'>(</span><span class='hs-varid'>x</span><span class='hs-conop'>:</span><span class='hs-varid'>xs</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></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-varid'>xs</span><span class='hs-layout'>)</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>)</span>
<a name="line-78"></a>
<a name="line-79"></a><a name="first"></a><span class='hs-definition'>first</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Parser</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Parser</span> <span class='hs-varid'>a</span>
<a name="line-80"></a><span class='hs-definition'>first</span> <span class='hs-layout'>(</span><span class='hs-conid'>P</span> <span class='hs-varid'>p</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>P</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>\</span><span class='hs-varid'>inp</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyword'>case</span> <span class='hs-varid'>p</span> <span class='hs-varid'>inp</span> <span class='hs-keyword'>of</span>
<a name="line-81"></a> <span class='hs-conid'>[]</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>[]</span>
<a name="line-82"></a> <span class='hs-layout'>(</span><span class='hs-varid'>x</span><span class='hs-conop'>:</span><span class='hs-keyword'>_</span><span class='hs-layout'>)</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-layout'>)</span>
<a name="line-83"></a>
<a name="line-84"></a><a name="papply"></a><span class='hs-definition'>papply</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Parser</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Token</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyglyph'>[</span><span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span><span class='hs-keyglyph'>[</span><span class='hs-conid'>Token</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>)</span><span class='hs-keyglyph'>]</span>
<a name="line-85"></a><span class='hs-definition'>papply</span> <span class='hs-layout'>(</span><span class='hs-conid'>P</span> <span class='hs-varid'>p</span><span class='hs-layout'>)</span> <span class='hs-varid'>inp</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>p</span> <span class='hs-varid'>inp</span>
<a name="line-86"></a>
<a name="line-87"></a><span class='hs-comment'>-- ------------------------------------------------------------</span>
<a name="line-88"></a><span class='hs-comment'>-- * Derived combinators</span>
<a name="line-89"></a><span class='hs-comment'>-- ------------------------------------------------------------</span>
<a name="line-90"></a>
<a name="line-91"></a><a name="+++"></a><span class='hs-layout'>(</span><span class='hs-varop'>+++</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Parser</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Parser</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Parser</span> <span class='hs-varid'>a</span>
<a name="line-92"></a><a name="p"></a><span class='hs-definition'>p</span> <span class='hs-varop'>+++</span> <span class='hs-varid'>q</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>first</span> <span class='hs-layout'>(</span><span class='hs-varid'>p</span> <span class='hs-varop'>`mplus`</span> <span class='hs-varid'>q</span><span class='hs-layout'>)</span>
<a name="line-93"></a>
<a name="line-94"></a><a name="sat"></a><span class='hs-definition'>sat</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>Token</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Bool</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Parser</span> <span class='hs-conid'>Token</span>
<a name="line-95"></a><span class='hs-definition'>sat</span> <span class='hs-varid'>p</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-layout'>{</span><span class='hs-varid'>x</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>item</span><span class='hs-layout'>;</span> <span class='hs-keyword'>if</span> <span class='hs-varid'>p</span> <span class='hs-varid'>x</span> <span class='hs-keyword'>then</span> <span class='hs-varid'>return</span> <span class='hs-varid'>x</span> <span class='hs-keyword'>else</span> <span class='hs-varid'>mzero</span><span class='hs-layout'>}</span>
<a name="line-96"></a>
<a name="line-97"></a><span class='hs-comment'>--tok :: Token -> Parser Token</span>
<a name="line-98"></a><span class='hs-comment'>--tok t = do {x <- item; if t==snd x then return t else mzero}</span>
<a name="line-99"></a>
<a name="line-100"></a><a name="many"></a><span class='hs-definition'>many</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Parser</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Parser</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>a</span><span class='hs-keyglyph'>]</span>
<a name="line-101"></a><span class='hs-definition'>many</span> <span class='hs-varid'>p</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>many1</span> <span class='hs-varid'>p</span> <span class='hs-varop'>+++</span> <span class='hs-varid'>return</span> <span class='hs-conid'>[]</span>
<a name="line-102"></a><span class='hs-comment'>--many p = force (many1 p +++ return [])</span>
<a name="line-103"></a>
<a name="line-104"></a><a name="many1"></a><span class='hs-definition'>many1</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Parser</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Parser</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>a</span><span class='hs-keyglyph'>]</span>
<a name="line-105"></a><span class='hs-definition'>many1</span> <span class='hs-varid'>p</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-layout'>{</span><span class='hs-varid'>x</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>p</span><span class='hs-layout'>;</span> <span class='hs-varid'>xs</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>many</span> <span class='hs-varid'>p</span><span class='hs-layout'>;</span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>x</span><span class='hs-conop'>:</span><span class='hs-varid'>xs</span><span class='hs-layout'>)</span><span class='hs-layout'>}</span>
<a name="line-106"></a>
<a name="line-107"></a><a name="sepby"></a><span class='hs-definition'>sepby</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Parser</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Parser</span> <span class='hs-varid'>b</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Parser</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>a</span><span class='hs-keyglyph'>]</span>
<a name="line-108"></a><a name="sepby"></a><span class='hs-definition'>p</span> <span class='hs-varop'>`sepby`</span> <span class='hs-varid'>sep</span> <span class='hs-keyglyph'>=</span> <span class='hs-layout'>(</span><span class='hs-varid'>p</span> <span class='hs-varop'>`sepby1`</span> <span class='hs-varid'>sep</span><span class='hs-layout'>)</span> <span class='hs-varop'>+++</span> <span class='hs-varid'>return</span> <span class='hs-conid'>[]</span>
<a name="line-109"></a>
<a name="line-110"></a><a name="sepby1"></a><span class='hs-definition'>sepby1</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Parser</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Parser</span> <span class='hs-varid'>b</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Parser</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>a</span><span class='hs-keyglyph'>]</span>
<a name="line-111"></a><a name="sepby1"></a><span class='hs-definition'>p</span> <span class='hs-varop'>`sepby1`</span> <span class='hs-varid'>sep</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-layout'>{</span><span class='hs-varid'>x</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>p</span><span class='hs-layout'>;</span> <span class='hs-varid'>xs</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>many</span> <span class='hs-layout'>(</span><span class='hs-keyword'>do</span> <span class='hs-layout'>{</span><span class='hs-varid'>sep</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-layout'>;</span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>x</span><span class='hs-conop'>:</span><span class='hs-varid'>xs</span><span class='hs-layout'>)</span><span class='hs-layout'>}</span>
<a name="line-112"></a>
<a name="line-113"></a><a name="chainl"></a><span class='hs-definition'>chainl</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Parser</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Parser</span> <span class='hs-layout'>(</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-varid'>a</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Parser</span> <span class='hs-varid'>a</span>
<a name="line-114"></a><span class='hs-definition'>chainl</span> <span class='hs-varid'>p</span> <span class='hs-varid'>op</span> <span class='hs-varid'>v</span> <span class='hs-keyglyph'>=</span> <span class='hs-layout'>(</span><span class='hs-varid'>p</span> <span class='hs-varop'>`chainl1`</span> <span class='hs-varid'>op</span><span class='hs-layout'>)</span> <span class='hs-varop'>+++</span> <span class='hs-varid'>return</span> <span class='hs-varid'>v</span>
<a name="line-115"></a>
<a name="line-116"></a><a name="chainl1"></a><span class='hs-definition'>chainl1</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Parser</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Parser</span> <span class='hs-layout'>(</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-varid'>a</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Parser</span> <span class='hs-varid'>a</span>
<a name="line-117"></a><a name="chainl1"></a><span class='hs-definition'>p</span> <span class='hs-varop'>`chainl1`</span> <span class='hs-varid'>op</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-layout'>{</span><span class='hs-varid'>x</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>p</span><span class='hs-layout'>;</span> <span class='hs-varid'>rest</span> <span class='hs-varid'>x</span><span class='hs-layout'>}</span>
<a name="line-118"></a> <span class='hs-keyword'>where</span>
<a name="line-119"></a> <span class='hs-varid'>rest</span> <span class='hs-varid'>x</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-layout'>{</span><span class='hs-varid'>f</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>op</span><span class='hs-layout'>;</span> <span class='hs-varid'>y</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>p</span><span class='hs-layout'>;</span> <span class='hs-varid'>rest</span> <span class='hs-layout'>(</span><span class='hs-varid'>f</span> <span class='hs-varid'>x</span> <span class='hs-varid'>y</span><span class='hs-layout'>)</span><span class='hs-layout'>}</span>
<a name="line-120"></a> <span class='hs-varop'>+++</span> <span class='hs-varid'>return</span> <span class='hs-varid'>x</span>
<a name="line-121"></a>
<a name="line-122"></a><a name="chainr"></a><span class='hs-definition'>chainr</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Parser</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Parser</span> <span class='hs-layout'>(</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-varid'>a</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Parser</span> <span class='hs-varid'>a</span>
<a name="line-123"></a><span class='hs-definition'>chainr</span> <span class='hs-varid'>p</span> <span class='hs-varid'>op</span> <span class='hs-varid'>v</span> <span class='hs-keyglyph'>=</span> <span class='hs-layout'>(</span><span class='hs-varid'>p</span> <span class='hs-varop'>`chainr1`</span> <span class='hs-varid'>op</span><span class='hs-layout'>)</span> <span class='hs-varop'>+++</span> <span class='hs-varid'>return</span> <span class='hs-varid'>v</span>
<a name="line-124"></a>
<a name="line-125"></a><a name="chainr1"></a><span class='hs-definition'>chainr1</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Parser</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Parser</span> <span class='hs-layout'>(</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-varid'>a</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Parser</span> <span class='hs-varid'>a</span>
<a name="line-126"></a><a name="chainr1"></a><span class='hs-definition'>p</span> <span class='hs-varop'>`chainr1`</span> <span class='hs-varid'>op</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-layout'>{</span><span class='hs-varid'>x</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>p</span><span class='hs-layout'>;</span> <span class='hs-varid'>rest</span> <span class='hs-varid'>x</span><span class='hs-layout'>}</span>
<a name="line-127"></a> <span class='hs-keyword'>where</span>
<a name="line-128"></a> <span class='hs-varid'>rest</span> <span class='hs-varid'>x</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-layout'>{</span><span class='hs-varid'>f</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>op</span><span class='hs-layout'>;</span> <span class='hs-varid'>y</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>p</span> <span class='hs-varop'>`chainr1`</span> <span class='hs-varid'>op</span><span class='hs-layout'>;</span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>f</span> <span class='hs-varid'>x</span> <span class='hs-varid'>y</span><span class='hs-layout'>)</span><span class='hs-layout'>}</span>
<a name="line-129"></a> <span class='hs-varop'>+++</span> <span class='hs-varid'>return</span> <span class='hs-varid'>x</span>
<a name="line-130"></a>
<a name="line-131"></a><a name="ops"></a><span class='hs-definition'>ops</span> <span class='hs-keyglyph'>::</span> <span class='hs-keyglyph'>[</span><span class='hs-layout'>(</span><span class='hs-conid'>Parser</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-keyglyph'>-></span> <span class='hs-conid'>Parser</span> <span class='hs-varid'>b</span>
<a name="line-132"></a><span class='hs-definition'>ops</span> <span class='hs-varid'>xs</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>foldr1</span> <span class='hs-layout'>(</span><span class='hs-varop'>+++</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>[</span><span class='hs-keyword'>do</span> <span class='hs-layout'>{</span><span class='hs-varid'>p</span><span class='hs-layout'>;</span> <span class='hs-varid'>return</span> <span class='hs-varid'>op</span><span class='hs-layout'>}</span> <span class='hs-keyglyph'>|</span> <span class='hs-layout'>(</span><span class='hs-varid'>p</span><span class='hs-layout'>,</span><span class='hs-varid'>op</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>xs</span><span class='hs-keyglyph'>]</span>
<a name="line-133"></a>
<a name="line-134"></a><a name="bracket"></a><span class='hs-definition'>bracket</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Parser</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Parser</span> <span class='hs-varid'>b</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Parser</span> <span class='hs-varid'>c</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Parser</span> <span class='hs-varid'>b</span>
<a name="line-135"></a><span class='hs-definition'>bracket</span> <span class='hs-varid'>open</span> <span class='hs-varid'>p</span> <span class='hs-varid'>close</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-layout'>{</span><span class='hs-varid'>open</span><span class='hs-layout'>;</span> <span class='hs-varid'>x</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>p</span><span class='hs-layout'>;</span> <span class='hs-varid'>close</span><span class='hs-layout'>;</span> <span class='hs-varid'>return</span> <span class='hs-varid'>x</span><span class='hs-layout'>}</span>
<a name="line-136"></a>
<a name="line-137"></a><span class='hs-comment'>-- ------------------------------------------------------------</span>
<a name="line-138"></a><span class='hs-comment'>-- * Useful parsers</span>
<a name="line-139"></a><span class='hs-comment'>-- ------------------------------------------------------------</span>
<a name="line-140"></a>
<a name="line-141"></a><a name="char"></a><span class='hs-definition'>char</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Char</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Parser</span> <span class='hs-conid'>Char</span>
<a name="line-142"></a><span class='hs-definition'>char</span> <span class='hs-varid'>x</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>sat</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>\</span><span class='hs-varid'>y</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>x</span> <span class='hs-varop'>==</span> <span class='hs-varid'>y</span><span class='hs-layout'>)</span>
<a name="line-143"></a>
<a name="line-144"></a><a name="digit"></a><span class='hs-definition'>digit</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Parser</span> <span class='hs-conid'>Char</span>
<a name="line-145"></a><span class='hs-definition'>digit</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>sat</span> <span class='hs-varid'>isDigit</span>
<a name="line-146"></a>
<a name="line-147"></a><a name="lower"></a><span class='hs-definition'>lower</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Parser</span> <span class='hs-conid'>Char</span>
<a name="line-148"></a><span class='hs-definition'>lower</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>sat</span> <span class='hs-varid'>isLower</span>
<a name="line-149"></a>
<a name="line-150"></a><a name="upper"></a><span class='hs-definition'>upper</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Parser</span> <span class='hs-conid'>Char</span>
<a name="line-151"></a><span class='hs-definition'>upper</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>sat</span> <span class='hs-varid'>isUpper</span>
<a name="line-152"></a>
<a name="line-153"></a><a name="letter"></a><span class='hs-definition'>letter</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Parser</span> <span class='hs-conid'>Char</span>
<a name="line-154"></a><span class='hs-definition'>letter</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>sat</span> <span class='hs-varid'>isAlpha</span>
<a name="line-155"></a>
<a name="line-156"></a><a name="alphanum"></a><span class='hs-definition'>alphanum</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Parser</span> <span class='hs-conid'>Char</span>
<a name="line-157"></a><span class='hs-definition'>alphanum</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>sat</span> <span class='hs-varid'>isAlphaNum</span> <span class='hs-varop'>+++</span> <span class='hs-varid'>char</span> <span class='hs-chr'>'_'</span>
<a name="line-158"></a>
<a name="line-159"></a><a name="string"></a><span class='hs-definition'>string</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>String</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Parser</span> <span class='hs-conid'>String</span>
<a name="line-160"></a><span class='hs-definition'>string</span> <span class='hs-str'>""</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>return</span> <span class='hs-str'>""</span>
<a name="line-161"></a><span class='hs-definition'>string</span> <span class='hs-layout'>(</span><span class='hs-varid'>x</span><span class='hs-conop'>:</span><span class='hs-varid'>xs</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-layout'>{</span><span class='hs-varid'>char</span> <span class='hs-varid'>x</span><span class='hs-layout'>;</span> <span class='hs-varid'>string</span> <span class='hs-varid'>xs</span><span class='hs-layout'>;</span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>x</span><span class='hs-conop'>:</span><span class='hs-varid'>xs</span><span class='hs-layout'>)</span><span class='hs-layout'>}</span>
<a name="line-162"></a>
<a name="line-163"></a><a name="ident"></a><span class='hs-definition'>ident</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Parser</span> <span class='hs-conid'>String</span>
<a name="line-164"></a><span class='hs-definition'>ident</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-layout'>{</span><span class='hs-varid'>x</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>lower</span><span class='hs-layout'>;</span> <span class='hs-varid'>xs</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>many</span> <span class='hs-varid'>alphanum</span><span class='hs-layout'>;</span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>x</span><span class='hs-conop'>:</span><span class='hs-varid'>xs</span><span class='hs-layout'>)</span><span class='hs-layout'>}</span>
<a name="line-165"></a>
<a name="line-166"></a><a name="nat"></a><span class='hs-definition'>nat</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Parser</span> <span class='hs-conid'>Int</span>
<a name="line-167"></a><span class='hs-definition'>nat</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-layout'>{</span><span class='hs-varid'>x</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>digit</span><span class='hs-layout'>;</span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>fromEnum</span> <span class='hs-varid'>x</span> <span class='hs-comment'>-</span> <span class='hs-varid'>fromEnum</span> <span class='hs-chr'>'0'</span><span class='hs-layout'>)</span><span class='hs-layout'>}</span> <span class='hs-varop'>`chainl1`</span> <span class='hs-varid'>return</span> <span class='hs-varid'>op</span>
<a name="line-168"></a> <span class='hs-keyword'>where</span>
<a name="line-169"></a> <span class='hs-varid'>m</span> <span class='hs-varop'>`op`</span> <span class='hs-varid'>n</span> <span class='hs-keyglyph'>=</span> <span class='hs-num'>10</span><span class='hs-varop'>*</span><span class='hs-varid'>m</span> <span class='hs-varop'>+</span> <span class='hs-varid'>n</span>
<a name="line-170"></a>
<a name="line-171"></a><a name="int"></a><span class='hs-definition'>int</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Parser</span> <span class='hs-conid'>Int</span>
<a name="line-172"></a><span class='hs-definition'>int</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-layout'>{</span><span class='hs-varid'>char</span> <span class='hs-chr'>'-'</span><span class='hs-layout'>;</span> <span class='hs-varid'>n</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>nat</span><span class='hs-layout'>;</span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-comment'>-</span><span class='hs-varid'>n</span><span class='hs-layout'>)</span><span class='hs-layout'>}</span> <span class='hs-varop'>+++</span> <span class='hs-varid'>nat</span>
<a name="line-173"></a>
<a name="line-174"></a><span class='hs-comment'>-- ------------------------------------------------------------</span>
<a name="line-175"></a><span class='hs-comment'>-- * Lexical combinators</span>
<a name="line-176"></a><span class='hs-comment'>-- ------------------------------------------------------------</span>
<a name="line-177"></a>
<a name="line-178"></a><a name="spaces"></a><span class='hs-definition'>spaces</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Parser</span> <span class='hs-conid'>()</span>
<a name="line-179"></a><span class='hs-definition'>spaces</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-layout'>{</span><span class='hs-varid'>many1</span> <span class='hs-layout'>(</span><span class='hs-varid'>sat</span> <span class='hs-varid'>isSpace</span><span class='hs-layout'>)</span><span class='hs-layout'>;</span> <span class='hs-varid'>return</span> <span class='hs-conid'>()</span><span class='hs-layout'>}</span>
<a name="line-180"></a>
<a name="line-181"></a><a name="comment"></a><span class='hs-definition'>comment</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Parser</span> <span class='hs-conid'>()</span>
<a name="line-182"></a><span class='hs-comment'>--comment = do {string "--"; many (sat (\x -> x /= '\n')); return ()}</span>
<a name="line-183"></a><span class='hs-comment'>--comment = do </span>
<a name="line-184"></a><span class='hs-comment'>-- _ <- string "--"</span>
<a name="line-185"></a><span class='hs-comment'>-- _ <- many (sat (\x -> x /= '\n'))</span>
<a name="line-186"></a><span class='hs-comment'>-- return ()</span>
<a name="line-187"></a><span class='hs-definition'>comment</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span>
<a name="line-188"></a> <span class='hs-varid'>bracket</span> <span class='hs-layout'>(</span><span class='hs-varid'>string</span> <span class='hs-str'>"/*"</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>many</span> <span class='hs-varid'>item</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>string</span> <span class='hs-str'>"*/"</span><span class='hs-layout'>)</span>
<a name="line-189"></a> <span class='hs-varid'>return</span> <span class='hs-conid'>()</span>
<a name="line-190"></a>
<a name="line-191"></a><a name="junk"></a><span class='hs-definition'>junk</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Parser</span> <span class='hs-conid'>()</span>
<a name="line-192"></a><span class='hs-definition'>junk</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-layout'>{</span><span class='hs-varid'>many</span> <span class='hs-layout'>(</span><span class='hs-varid'>spaces</span> <span class='hs-varop'>+++</span> <span class='hs-varid'>comment</span><span class='hs-layout'>)</span><span class='hs-layout'>;</span> <span class='hs-varid'>return</span> <span class='hs-conid'>()</span><span class='hs-layout'>}</span>
<a name="line-193"></a>
<a name="line-194"></a><a name="skip"></a><span class='hs-definition'>skip</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Parser</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Parser</span> <span class='hs-varid'>a</span>
<a name="line-195"></a><span class='hs-definition'>skip</span> <span class='hs-varid'>p</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-layout'>{</span><span class='hs-varid'>junk</span><span class='hs-layout'>;</span> <span class='hs-varid'>p</span><span class='hs-layout'>}</span>
<a name="line-196"></a>
<a name="line-197"></a><a name="token"></a><span class='hs-definition'>token</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Parser</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Parser</span> <span class='hs-varid'>a</span>
<a name="line-198"></a><span class='hs-definition'>token</span> <span class='hs-varid'>p</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-layout'>{</span><span class='hs-varid'>v</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>p</span><span class='hs-layout'>;</span> <span class='hs-varid'>junk</span><span class='hs-layout'>;</span> <span class='hs-varid'>return</span> <span class='hs-varid'>v</span><span class='hs-layout'>}</span>
<a name="line-199"></a>
<a name="line-200"></a><span class='hs-comment'>-- ------------------------------------------------------------</span>
<a name="line-201"></a><span class='hs-comment'>-- * Token parsers</span>
<a name="line-202"></a><span class='hs-comment'>-- ------------------------------------------------------------</span>
<a name="line-203"></a>
<a name="line-204"></a><a name="natural"></a><span class='hs-definition'>natural</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Parser</span> <span class='hs-conid'>Int</span>
<a name="line-205"></a><span class='hs-definition'>natural</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>token</span> <span class='hs-varid'>nat</span>
<a name="line-206"></a>
<a name="line-207"></a><a name="integer"></a><span class='hs-definition'>integer</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Parser</span> <span class='hs-conid'>Int</span>
<a name="line-208"></a><span class='hs-definition'>integer</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>token</span> <span class='hs-varid'>int</span>
<a name="line-209"></a>
<a name="line-210"></a><a name="symbol"></a><span class='hs-definition'>symbol</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>String</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Parser</span> <span class='hs-conid'>String</span>
<a name="line-211"></a><span class='hs-definition'>symbol</span> <span class='hs-varid'>xs</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>token</span> <span class='hs-layout'>(</span><span class='hs-varid'>string</span> <span class='hs-varid'>xs</span><span class='hs-layout'>)</span>
<a name="line-212"></a>
<a name="line-213"></a><a name="identifier"></a><span class='hs-definition'>identifier</span> <span class='hs-keyglyph'>::</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>String</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Parser</span> <span class='hs-conid'>String</span>
<a name="line-214"></a><span class='hs-definition'>identifier</span> <span class='hs-varid'>ks</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>token</span> <span class='hs-layout'>(</span><span class='hs-keyword'>do</span> <span class='hs-layout'>{</span><span class='hs-varid'>x</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>ident</span><span class='hs-layout'>;</span>
<a name="line-215"></a> <span class='hs-keyword'>if</span> <span class='hs-varid'>not</span> <span class='hs-layout'>(</span><span class='hs-varid'>elem</span> <span class='hs-varid'>x</span> <span class='hs-varid'>ks</span><span class='hs-layout'>)</span> <span class='hs-keyword'>then</span> <span class='hs-varid'>return</span> <span class='hs-varid'>x</span>
<a name="line-216"></a> <span class='hs-keyword'>else</span> <span class='hs-varid'>return</span> <span class='hs-varid'>mzero</span><span class='hs-layout'>}</span><span class='hs-layout'>)</span>
<a name="line-217"></a>
<a name="line-218"></a><span class='hs-comment'>------------------------------------------------------------------------------</span>
</pre></body>
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