/usr/share/doc/libghc-polyparse-doc/html/src/Text-ParserCombinators-Poly-Lex.html is in libghc-polyparse-doc 1.7-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 | <?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html>
<head>
<!-- Generated by HsColour, http://code.haskell.org/~malcolm/hscolour/ -->
<title>src/Text/ParserCombinators/Poly/Lex.hs</title>
<link type='text/css' rel='stylesheet' href='hscolour.css' />
</head>
<body>
<pre><a name="line-1"></a><span class='hs-comment'>-- Author: Malcolm Wallace</span>
<a name="line-2"></a>
<a name="line-3"></a><span class='hs-comment'>-- | In a strict language, where creating the entire input list of tokens</span>
<a name="line-4"></a><span class='hs-comment'>-- in one shot may be infeasible, we can use a lazy "callback" kind of</span>
<a name="line-5"></a><span class='hs-comment'>-- architecture instead. The lexer returns a single token at a time,</span>
<a name="line-6"></a><span class='hs-comment'>-- together with a continuation.</span>
<a name="line-7"></a><span class='hs-comment'>--</span>
<a name="line-8"></a><span class='hs-comment'>-- This module defines a Parser type (capable of use with the Poly</span>
<a name="line-9"></a><span class='hs-comment'>-- combinators), specialised to the callback-lexer style of input stream.</span>
<a name="line-10"></a>
<a name="line-11"></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'>Poly</span><span class='hs-varop'>.</span><span class='hs-conid'>Lex</span>
<a name="line-12"></a> <span class='hs-layout'>(</span> <span class='hs-comment'>-- * The Parser datatype</span>
<a name="line-13"></a> <span class='hs-conid'>LexReturn</span><span class='hs-layout'>(</span><span class='hs-keyglyph'>..</span><span class='hs-layout'>)</span>
<a name="line-14"></a> <span class='hs-layout'>,</span> <span class='hs-conid'>Parser</span><span class='hs-layout'>(</span><span class='hs-conid'>P</span><span class='hs-layout'>)</span>
<a name="line-15"></a> <span class='hs-layout'>,</span> <span class='hs-conid'>Result</span><span class='hs-layout'>(</span><span class='hs-keyglyph'>..</span><span class='hs-layout'>)</span>
<a name="line-16"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>runParser</span>
<a name="line-17"></a> <span class='hs-comment'>-- ** Basic parsers</span>
<a name="line-18"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>next</span>
<a name="line-19"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>eof</span>
<a name="line-20"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>satisfy</span>
<a name="line-21"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>onFail</span>
<a name="line-22"></a> <span class='hs-comment'>-- ** Re-parsing</span>
<a name="line-23"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>reparse</span>
<a name="line-24"></a> <span class='hs-comment'>-- * Re-export all more general combinators</span>
<a name="line-25"></a> <span class='hs-layout'>,</span> <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'>Poly</span><span class='hs-varop'>.</span><span class='hs-conid'>Base</span>
<a name="line-26"></a> <span class='hs-layout'>,</span> <span class='hs-keyword'>module</span> <span class='hs-conid'>Control</span><span class='hs-varop'>.</span><span class='hs-conid'>Applicative</span>
<a name="line-27"></a> <span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-28"></a>
<a name="line-29"></a>
<a name="line-30"></a><span class='hs-keyword'>import</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'>Poly</span><span class='hs-varop'>.</span><span class='hs-conid'>Base</span>
<a name="line-31"></a><span class='hs-keyword'>import</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'>Poly</span><span class='hs-varop'>.</span><span class='hs-conid'>Result</span>
<a name="line-32"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Control</span><span class='hs-varop'>.</span><span class='hs-conid'>Applicative</span>
<a name="line-33"></a>
<a name="line-34"></a><a name="LexReturn"></a><span class='hs-comment'>-- | In a strict language, where creating the entire input list of tokens</span>
<a name="line-35"></a><a name="LexReturn"></a><span class='hs-comment'>-- in one shot may be infeasible, we can use a lazy "callback" kind of</span>
<a name="line-36"></a><a name="LexReturn"></a><span class='hs-comment'>-- architecture instead. The lexer returns a single token at a time,</span>
<a name="line-37"></a><a name="LexReturn"></a><span class='hs-comment'>-- together with a continuation. The @next@ parser is responsible for </span>
<a name="line-38"></a><a name="LexReturn"></a><span class='hs-comment'>-- pulling on the token stream, applying the continuation where necessary.</span>
<a name="line-39"></a><a name="LexReturn"></a><span class='hs-keyword'>data</span> <span class='hs-conid'>LexReturn</span> <span class='hs-varid'>t</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>LexReturn</span> <span class='hs-varid'>t</span> <span class='hs-conid'>String</span> <span class='hs-layout'>(</span><span class='hs-conid'>String</span><span class='hs-keyglyph'>-></span><span class='hs-conid'>LexReturn</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span>
<a name="line-40"></a> <span class='hs-keyglyph'>|</span> <span class='hs-conid'>LexFinish</span>
<a name="line-41"></a>
<a name="line-42"></a><a name="Parser"></a><span class='hs-comment'>-- | This @Parser@ datatype is a specialised parsing monad with error</span>
<a name="line-43"></a><a name="Parser"></a><span class='hs-comment'>-- reporting. This version is specialised to pre-lexed String input,</span>
<a name="line-44"></a><a name="Parser"></a><span class='hs-comment'>-- where the lexer has been written to yield a @LexReturn@.</span>
<a name="line-45"></a><a name="Parser"></a><span class='hs-keyword'>newtype</span> <span class='hs-conid'>Parser</span> <span class='hs-varid'>t</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-conid'>LexReturn</span> <span class='hs-varid'>t</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Result</span> <span class='hs-layout'>(</span><span class='hs-conid'>LexReturn</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span>
<a name="line-46"></a>
<a name="line-47"></a><a name="runParser"></a><span class='hs-comment'>-- | Apply a parser to an input token sequence.</span>
<a name="line-48"></a><span class='hs-definition'>runParser</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Parser</span> <span class='hs-varid'>t</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>LexReturn</span> <span class='hs-varid'>t</span> <span class='hs-keyglyph'>-></span> <span class='hs-layout'>(</span><span class='hs-conid'>Either</span> <span class='hs-conid'>String</span> <span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-conid'>String</span><span class='hs-layout'>)</span>
<a name="line-49"></a><span class='hs-definition'>runParser</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-layout'>(</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-varid'>b</span><span class='hs-layout'>)</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-varid'>stripLex</span> <span class='hs-varid'>b</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-varop'>.</span> <span class='hs-varid'>resultToEither</span> <span class='hs-varop'>.</span> <span class='hs-varid'>p</span>
<a name="line-50"></a> <span class='hs-keyword'>where</span> <span class='hs-varid'>stripLex</span> <span class='hs-conid'>LexFinish</span> <span class='hs-keyglyph'>=</span> <span class='hs-str'>""</span>
<a name="line-51"></a> <span class='hs-varid'>stripLex</span> <span class='hs-layout'>(</span><span class='hs-conid'>LexReturn</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>s</span> <span class='hs-keyword'>_</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>s</span>
<a name="line-52"></a>
<a name="line-53"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>Functor</span> <span class='hs-layout'>(</span><span class='hs-conid'>Parser</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-54"></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-varid'>fmap</span> <span class='hs-varid'>f</span> <span class='hs-varop'>.</span> <span class='hs-varid'>p</span><span class='hs-layout'>)</span>
<a name="line-55"></a>
<a name="line-56"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>Monad</span> <span class='hs-layout'>(</span><span class='hs-conid'>Parser</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-57"></a> <span class='hs-varid'>return</span> <span class='hs-varid'>x</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'>ts</span><span class='hs-keyglyph'>-></span> <span class='hs-conid'>Success</span> <span class='hs-varid'>ts</span> <span class='hs-varid'>x</span><span class='hs-layout'>)</span>
<a name="line-58"></a> <span class='hs-varid'>fail</span> <span class='hs-varid'>e</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'>ts</span><span class='hs-keyglyph'>-></span> <span class='hs-conid'>Failure</span> <span class='hs-varid'>ts</span> <span class='hs-varid'>e</span><span class='hs-layout'>)</span>
<a name="line-59"></a> <span class='hs-layout'>(</span><span class='hs-conid'>P</span> <span class='hs-varid'>f</span><span class='hs-layout'>)</span> <span class='hs-varop'>>>=</span> <span class='hs-varid'>g</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>P</span> <span class='hs-layout'>(</span><span class='hs-varid'>continue</span> <span class='hs-varop'>.</span> <span class='hs-varid'>f</span><span class='hs-layout'>)</span>
<a name="line-60"></a> <span class='hs-keyword'>where</span>
<a name="line-61"></a> <span class='hs-varid'>continue</span> <span class='hs-layout'>(</span><span class='hs-conid'>Success</span> <span class='hs-varid'>ts</span> <span class='hs-varid'>x</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>let</span> <span class='hs-layout'>(</span><span class='hs-conid'>P</span> <span class='hs-varid'>g'</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>g</span> <span class='hs-varid'>x</span> <span class='hs-keyword'>in</span> <span class='hs-varid'>g'</span> <span class='hs-varid'>ts</span>
<a name="line-62"></a> <span class='hs-varid'>continue</span> <span class='hs-layout'>(</span><span class='hs-conid'>Committed</span> <span class='hs-layout'>(</span><span class='hs-conid'>Committed</span> <span class='hs-varid'>r</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>continue</span> <span class='hs-layout'>(</span><span class='hs-conid'>Committed</span> <span class='hs-varid'>r</span><span class='hs-layout'>)</span>
<a name="line-63"></a> <span class='hs-varid'>continue</span> <span class='hs-layout'>(</span><span class='hs-conid'>Committed</span> <span class='hs-varid'>r</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Committed</span> <span class='hs-layout'>(</span><span class='hs-varid'>continue</span> <span class='hs-varid'>r</span><span class='hs-layout'>)</span>
<a name="line-64"></a> <span class='hs-varid'>continue</span> <span class='hs-layout'>(</span><span class='hs-conid'>Failure</span> <span class='hs-varid'>ts</span> <span class='hs-varid'>e</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Failure</span> <span class='hs-varid'>ts</span> <span class='hs-varid'>e</span>
<a name="line-65"></a>
<a name="line-66"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>Commitment</span> <span class='hs-layout'>(</span><span class='hs-conid'>Parser</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-67"></a> <span class='hs-varid'>commit</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-conid'>Committed</span> <span class='hs-varop'>.</span> <span class='hs-varid'>p</span><span class='hs-layout'>)</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'>`adjustErr`</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-varid'>adjust</span> <span class='hs-varop'>.</span> <span class='hs-varid'>p</span><span class='hs-layout'>)</span>
<a name="line-69"></a> <span class='hs-keyword'>where</span>
<a name="line-70"></a> <span class='hs-varid'>adjust</span> <span class='hs-layout'>(</span><span class='hs-conid'>Failure</span> <span class='hs-varid'>z</span> <span class='hs-varid'>e</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Failure</span> <span class='hs-varid'>z</span> <span class='hs-layout'>(</span><span class='hs-varid'>f</span> <span class='hs-varid'>e</span><span class='hs-layout'>)</span>
<a name="line-71"></a> <span class='hs-varid'>adjust</span> <span class='hs-layout'>(</span><span class='hs-conid'>Committed</span> <span class='hs-varid'>r</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Committed</span> <span class='hs-layout'>(</span><span class='hs-varid'>adjust</span> <span class='hs-varid'>r</span><span class='hs-layout'>)</span>
<a name="line-72"></a> <span class='hs-varid'>adjust</span> <span class='hs-varid'>good</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>good</span>
<a name="line-73"></a>
<a name="line-74"></a> <span class='hs-varid'>oneOf'</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>accum</span> <span class='hs-conid'>[]</span>
<a name="line-75"></a> <span class='hs-keyword'>where</span> <span class='hs-varid'>accum</span> <span class='hs-varid'>errs</span> <span class='hs-conid'>[]</span> <span class='hs-keyglyph'>=</span>
<a name="line-76"></a> <span class='hs-varid'>fail</span> <span class='hs-layout'>(</span><span class='hs-str'>"failed to parse any of the possible choices:\n"</span>
<a name="line-77"></a> <span class='hs-varop'>++</span><span class='hs-layout'>(</span><span class='hs-varid'>indent</span> <span class='hs-num'>2</span> <span class='hs-varop'>.</span> <span class='hs-varid'>unlines</span> <span class='hs-varop'>.</span> <span class='hs-varid'>map</span> <span class='hs-varid'>showErr</span> <span class='hs-varop'>.</span> <span class='hs-varid'>reverse</span> <span class='hs-varop'>$</span> <span class='hs-varid'>errs</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-78"></a> <span class='hs-varid'>accum</span> <span class='hs-varid'>errs</span> <span class='hs-layout'>(</span><span class='hs-layout'>(</span><span class='hs-varid'>e</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-conop'>:</span><span class='hs-varid'>ps</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span>
<a name="line-79"></a> <span class='hs-conid'>P</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>\</span><span class='hs-varid'>ts</span><span class='hs-keyglyph'>-></span> <span class='hs-keyword'>case</span> <span class='hs-varid'>p</span> <span class='hs-varid'>ts</span> <span class='hs-keyword'>of</span>
<a name="line-80"></a> <span class='hs-conid'>Failure</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>err</span> <span class='hs-keyglyph'>-></span>
<a name="line-81"></a> <span class='hs-keyword'>let</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-varid'>accum</span> <span class='hs-layout'>(</span><span class='hs-layout'>(</span><span class='hs-varid'>e</span><span class='hs-layout'>,</span><span class='hs-varid'>err</span><span class='hs-layout'>)</span><span class='hs-conop'>:</span><span class='hs-varid'>errs</span><span class='hs-layout'>)</span> <span class='hs-varid'>ps</span>
<a name="line-82"></a> <span class='hs-keyword'>in</span> <span class='hs-varid'>p'</span> <span class='hs-varid'>ts</span>
<a name="line-83"></a> <span class='hs-varid'>r</span><span class='hs-keyglyph'>@</span><span class='hs-layout'>(</span><span class='hs-conid'>Success</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>r</span>
<a name="line-84"></a> <span class='hs-varid'>r</span><span class='hs-keyglyph'>@</span><span class='hs-layout'>(</span><span class='hs-conid'>Committed</span> <span class='hs-keyword'>_</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>r</span> <span class='hs-layout'>)</span>
<a name="line-85"></a> <span class='hs-varid'>showErr</span> <span class='hs-layout'>(</span><span class='hs-varid'>name</span><span class='hs-layout'>,</span><span class='hs-varid'>err</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>name</span> <span class='hs-varop'>++</span> <span class='hs-str'>"\n"</span> <span class='hs-varop'>++</span> <span class='hs-varid'>indent</span> <span class='hs-num'>2</span> <span class='hs-varid'>err</span>
<a name="line-86"></a>
<a name="line-87"></a><span class='hs-keyword'>infixl</span> <span class='hs-num'>6</span> <span class='hs-varop'>`onFail`</span> <span class='hs-comment'>-- not sure about precedence 6?</span>
<a name="line-88"></a>
<a name="line-89"></a><a name="onFail"></a><span class='hs-comment'>-- | @p `onFail` q@ means parse p, unless p fails, in which case</span>
<a name="line-90"></a><a name="onFail"></a><span class='hs-comment'>-- parse q instead.</span>
<a name="line-91"></a><a name="onFail"></a><span class='hs-comment'>-- Can be chained together to give multiple attempts to parse something.</span>
<a name="line-92"></a><a name="onFail"></a><span class='hs-comment'>-- (Note that q could itself be a failing parser, e.g. to change the error</span>
<a name="line-93"></a><a name="onFail"></a><span class='hs-comment'>-- message from that defined in p to something different.)</span>
<a name="line-94"></a><a name="onFail"></a><span class='hs-comment'>-- However, a severe failure in p cannot be ignored.</span>
<a name="line-95"></a><a name="onFail"></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'>`onFail`</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'>ts</span><span class='hs-keyglyph'>-></span> <span class='hs-varid'>continue</span> <span class='hs-varid'>ts</span> <span class='hs-varop'>$</span> <span class='hs-varid'>p</span> <span class='hs-varid'>ts</span><span class='hs-layout'>)</span>
<a name="line-96"></a> <span class='hs-keyword'>where</span>
<a name="line-97"></a> <span class='hs-varid'>continue</span> <span class='hs-varid'>ts</span> <span class='hs-layout'>(</span><span class='hs-conid'>Failure</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>q</span> <span class='hs-varid'>ts</span>
<a name="line-98"></a> <span class='hs-comment'>-- continue _ (Committed r) = r -- no, remain Committed</span>
<a name="line-99"></a> <span class='hs-varid'>continue</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>r</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>r</span>
<a name="line-100"></a>
<a name="line-101"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>Applicative</span> <span class='hs-layout'>(</span><span class='hs-conid'>Parser</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-102"></a> <span class='hs-varid'>pure</span> <span class='hs-varid'>f</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>return</span> <span class='hs-varid'>f</span>
<a name="line-103"></a> <span class='hs-varid'>pf</span> <span class='hs-varop'><*></span> <span class='hs-varid'>px</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'>pf</span><span class='hs-layout'>;</span> <span class='hs-varid'>x</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>px</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-layout'>)</span> <span class='hs-layout'>}</span>
<a name="line-104"></a><span class='hs-cpp'>#if defined(GLASGOW_HASKELL) && GLASGOW_HASKELL > 610</span>
<a name="line-105"></a> <span class='hs-varid'>p</span> <span class='hs-varop'><*</span> <span class='hs-varid'>q</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>p</span> <span class='hs-varop'>`discard`</span> <span class='hs-varid'>q</span>
<a name="line-106"></a><span class='hs-cpp'>#endif</span>
<a name="line-107"></a>
<a name="line-108"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>Alternative</span> <span class='hs-layout'>(</span><span class='hs-conid'>Parser</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-109"></a> <span class='hs-varid'>empty</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>fail</span> <span class='hs-str'>"no parse"</span>
<a name="line-110"></a> <span class='hs-varid'>p</span> <span class='hs-varop'><|></span> <span class='hs-varid'>q</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>p</span> <span class='hs-varop'>`onFail`</span> <span class='hs-varid'>q</span>
<a name="line-111"></a>
<a name="line-112"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>PolyParse</span> <span class='hs-layout'>(</span><span class='hs-conid'>Parser</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span>
<a name="line-113"></a>
<a name="line-114"></a><span class='hs-comment'>------------------------------------------------------------------------</span>
<a name="line-115"></a>
<a name="line-116"></a><a name="next"></a><span class='hs-comment'>-- | Simply return the next token in the input tokenstream.</span>
<a name="line-117"></a><span class='hs-definition'>next</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Parser</span> <span class='hs-varid'>t</span> <span class='hs-varid'>t</span>
<a name="line-118"></a><span class='hs-definition'>next</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'>ts</span><span class='hs-keyglyph'>-></span> <span class='hs-keyword'>case</span> <span class='hs-varid'>ts</span> <span class='hs-keyword'>of</span>
<a name="line-119"></a> <span class='hs-conid'>LexFinish</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Failure</span> <span class='hs-varid'>ts</span> <span class='hs-str'>"Ran out of input (EOF)"</span>
<a name="line-120"></a> <span class='hs-conid'>LexReturn</span> <span class='hs-varid'>t</span> <span class='hs-varid'>s</span> <span class='hs-varid'>k</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Success</span> <span class='hs-layout'>(</span><span class='hs-varid'>k</span> <span class='hs-varid'>s</span><span class='hs-layout'>)</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span>
<a name="line-121"></a>
<a name="line-122"></a><a name="eof"></a><span class='hs-comment'>-- | Succeed if the end of file/input has been reached, fail otherwise.</span>
<a name="line-123"></a><span class='hs-definition'>eof</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Parser</span> <span class='hs-varid'>t</span> <span class='hs-conid'>()</span>
<a name="line-124"></a><span class='hs-definition'>eof</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'>ts</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyword'>case</span> <span class='hs-varid'>ts</span> <span class='hs-keyword'>of</span>
<a name="line-125"></a> <span class='hs-conid'>LexFinish</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Success</span> <span class='hs-varid'>ts</span> <span class='hs-conid'>()</span>
<a name="line-126"></a> <span class='hs-conid'>LexReturn</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'>Failure</span> <span class='hs-varid'>ts</span> <span class='hs-str'>"Expected end of input (EOF)"</span> <span class='hs-layout'>)</span>
<a name="line-127"></a>
<a name="line-128"></a><a name="satisfy"></a><span class='hs-comment'>-- | Return the next token if it satisfies the given predicate.</span>
<a name="line-129"></a><span class='hs-definition'>satisfy</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-varid'>t</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-varid'>t</span> <span class='hs-varid'>t</span>
<a name="line-130"></a><span class='hs-definition'>satisfy</span> <span class='hs-varid'>f</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'>next</span>
<a name="line-131"></a> <span class='hs-layout'>;</span> <span class='hs-keyword'>if</span> <span class='hs-varid'>f</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'>fail</span> <span class='hs-str'>"Parse.satisfy: failed"</span>
<a name="line-132"></a> <span class='hs-layout'>}</span>
<a name="line-133"></a>
<a name="line-134"></a><a name="reparse"></a><span class='hs-comment'>------------------------------------------------------------------------</span>
<a name="line-135"></a><span class='hs-comment'>-- | Push some tokens back onto the front of the input stream and reparse.</span>
<a name="line-136"></a><span class='hs-comment'>-- This is useful e.g. for recursively expanding macros. When the</span>
<a name="line-137"></a><span class='hs-comment'>-- user-parser recognises a macro use, it can lookup the macro</span>
<a name="line-138"></a><span class='hs-comment'>-- expansion from the parse state, lex it, and then stuff the</span>
<a name="line-139"></a><span class='hs-comment'>-- lexed expansion back down into the parser.</span>
<a name="line-140"></a><span class='hs-definition'>reparse</span> <span class='hs-keyglyph'>::</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>t</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Parser</span> <span class='hs-varid'>t</span> <span class='hs-conid'>()</span>
<a name="line-141"></a><span class='hs-definition'>reparse</span> <span class='hs-varid'>ts</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-conid'>Success</span> <span class='hs-layout'>(</span><span class='hs-varid'>ts</span> <span class='hs-varop'>`prefix`</span> <span class='hs-varid'>inp</span><span class='hs-layout'>)</span> <span class='hs-conid'>()</span><span class='hs-layout'>)</span>
<a name="line-142"></a> <span class='hs-keyword'>where</span>
<a name="line-143"></a> <span class='hs-layout'>(</span><span class='hs-varid'>t</span><span class='hs-conop'>:</span><span class='hs-varid'>ts</span><span class='hs-layout'>)</span> <span class='hs-varop'>`prefix`</span> <span class='hs-varid'>k</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>LexReturn</span> <span class='hs-varid'>t</span> <span class='hs-str'>""</span> <span class='hs-layout'>(</span><span class='hs-varid'>const</span> <span class='hs-layout'>(</span><span class='hs-varid'>ts</span> <span class='hs-varop'>`prefix`</span> <span class='hs-varid'>k</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-144"></a> <span class='hs-conid'>[]</span> <span class='hs-varop'>`prefix`</span> <span class='hs-varid'>k</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>k</span>
<a name="line-145"></a>
<a name="line-146"></a><span class='hs-comment'>------------------------------------------------------------------------</span>
</pre></body>
</html>
|