hxt-8.2.0: doc/hdoc/src/Text-XML-HXT-RelaxNG-XmlSchema-Regex.html
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<pre><a name="line-1"></a><span class='comment'>-- ------------------------------------------------------------</span>
<a name="line-2"></a>
<a name="line-3"></a><span class='comment'>{- |
<a name="line-4"></a> Module : Text.XML.HXT.RelaxNG.XmlSchema.Regex
<a name="line-5"></a> Copyright : Copyright (C) 2005 Uwe Schmidt
<a name="line-6"></a> License : MIT
<a name="line-7"></a>
<a name="line-8"></a> Maintainer : Uwe Schmidt (uwe@fh-wedel.de)
<a name="line-9"></a> Stability : experimental
<a name="line-10"></a> Portability: portable
<a name="line-11"></a>
<a name="line-12"></a> W3C XML Schema Regular Expression Matcher
<a name="line-13"></a>
<a name="line-14"></a> Grammar can be found under <<a href="http://www.w3.org/TR/xmlschema11-2/#regexs">http://www.w3.org/TR/xmlschema11-2/#regexs</a>>
<a name="line-15"></a>
<a name="line-16"></a>-}</span>
<a name="line-17"></a>
<a name="line-18"></a><span class='comment'>-- ------------------------------------------------------------</span>
<a name="line-19"></a>
<a name="line-20"></a><span class='keyword'>module</span> <span class='conid'>Text</span><span class='varop'>.</span><span class='conid'>XML</span><span class='varop'>.</span><span class='conid'>HXT</span><span class='varop'>.</span><span class='conid'>RelaxNG</span><span class='varop'>.</span><span class='conid'>XmlSchema</span><span class='varop'>.</span><span class='conid'>Regex</span>
<a name="line-21"></a> <span class='layout'>(</span> <span class='conid'>Regex</span>
<a name="line-22"></a> <span class='layout'>,</span> <span class='varid'>chars</span>
<a name="line-23"></a> <span class='layout'>,</span> <span class='varid'>charRngs</span>
<a name="line-24"></a> <span class='layout'>,</span> <span class='varid'>mkZero</span>
<a name="line-25"></a> <span class='layout'>,</span> <span class='varid'>mkUnit</span>
<a name="line-26"></a> <span class='layout'>,</span> <span class='varid'>mkSym</span>
<a name="line-27"></a> <span class='layout'>,</span> <span class='varid'>mkSym1</span>
<a name="line-28"></a> <span class='layout'>,</span> <span class='varid'>mkSymRng</span>
<a name="line-29"></a> <span class='layout'>,</span> <span class='varid'>mkDot</span>
<a name="line-30"></a> <span class='layout'>,</span> <span class='varid'>mkStar</span>
<a name="line-31"></a> <span class='layout'>,</span> <span class='varid'>mkAlt</span>
<a name="line-32"></a> <span class='layout'>,</span> <span class='varid'>mkSeq</span>
<a name="line-33"></a> <span class='layout'>,</span> <span class='varid'>mkRep</span>
<a name="line-34"></a> <span class='layout'>,</span> <span class='varid'>mkRng</span>
<a name="line-35"></a> <span class='layout'>,</span> <span class='varid'>mkOpt</span>
<a name="line-36"></a> <span class='layout'>,</span> <span class='varid'>mkDif</span>
<a name="line-37"></a> <span class='layout'>,</span> <span class='varid'>mkCompl</span>
<a name="line-38"></a> <span class='layout'>,</span> <span class='varid'>isZero</span>
<a name="line-39"></a> <span class='layout'>,</span> <span class='varid'>nullable</span>
<a name="line-40"></a> <span class='layout'>,</span> <span class='varid'>delta</span>
<a name="line-41"></a> <span class='layout'>,</span> <span class='varid'>matchWithRE</span>
<a name="line-42"></a> <span class='layout'>)</span>
<a name="line-43"></a><span class='keyword'>where</span>
<a name="line-44"></a>
<a name="line-45"></a><span class='keyword'>import</span> <span class='conid'>Data</span><span class='varop'>.</span><span class='conid'>Maybe</span>
<a name="line-46"></a>
<a name="line-47"></a><span class='comment'>-- ------------------------------------------------------------</span>
<a name="line-48"></a>
<a name="line-49"></a><a name="Regex"></a><span class='keyword'>data</span> <span class='conid'>Regex</span> <span class='keyglyph'>=</span> <span class='conid'>Zero</span> <span class='conid'>String</span>
<a name="line-50"></a> <span class='keyglyph'>|</span> <span class='conid'>Unit</span>
<a name="line-51"></a> <span class='keyglyph'>|</span> <span class='conid'>Sym</span> <span class='layout'>(</span><span class='conid'>Char</span> <span class='keyglyph'>-></span> <span class='conid'>Bool</span><span class='layout'>)</span>
<a name="line-52"></a> <span class='keyglyph'>|</span> <span class='conid'>Dot</span>
<a name="line-53"></a> <span class='keyglyph'>|</span> <span class='conid'>Star</span> <span class='conid'>Regex</span>
<a name="line-54"></a> <span class='keyglyph'>|</span> <span class='conid'>Alt</span> <span class='conid'>Regex</span> <span class='conid'>Regex</span>
<a name="line-55"></a> <span class='keyglyph'>|</span> <span class='conid'>Seq</span> <span class='conid'>Regex</span> <span class='conid'>Regex</span>
<a name="line-56"></a> <span class='keyglyph'>|</span> <span class='conid'>Rep</span> <span class='conid'>Int</span> <span class='conid'>Regex</span> <span class='comment'>-- 1 or more repetitions</span>
<a name="line-57"></a> <span class='keyglyph'>|</span> <span class='conid'>Rng</span> <span class='conid'>Int</span> <span class='conid'>Int</span> <span class='conid'>Regex</span> <span class='comment'>-- n..m repetitions</span>
<a name="line-58"></a> <span class='keyglyph'>|</span> <span class='conid'>Dif</span> <span class='conid'>Regex</span> <span class='conid'>Regex</span> <span class='comment'>-- r1 - r2</span>
<a name="line-59"></a>
<a name="line-60"></a><span class='comment'>-- ------------------------------------------------------------</span>
<a name="line-61"></a>
<a name="line-62"></a><span class='comment'>{- just for documentation
<a name="line-63"></a>
<a name="line-64"></a>class Inv a where
<a name="line-65"></a> inv :: a -> Bool
<a name="line-66"></a>
<a name="line-67"></a>instance Inv Regex where
<a name="line-68"></a> inv (Zero _) = True
<a name="line-69"></a> inv Unit = True
<a name="line-70"></a> inv (Sym p) = not . null . chars $ p
<a name="line-71"></a> inv Dot = True
<a name="line-72"></a> inv (Star e) = inv e
<a name="line-73"></a> inv (Alt e1 e2) = inv e1 &&
<a name="line-74"></a> inv e2
<a name="line-75"></a> inv (Seq e1 e2) = inv e1 &&
<a name="line-76"></a> inv e2
<a name="line-77"></a> inv (Rep i e) = i > 0 && inv e
<a name="line-78"></a> inv (Rng i j e) = (i < j || (i == j && i > 1)) &&
<a name="line-79"></a> inv e
<a name="line-80"></a> inv (Dif e1 e2) = inv e1 &&
<a name="line-81"></a> inv e2
<a name="line-82"></a>-}</span>
<a name="line-83"></a><span class='comment'>-- ------------------------------------------------------------</span>
<a name="line-84"></a><span class='comment'>--</span>
<a name="line-85"></a><span class='comment'>-- smart constructors</span>
<a name="line-86"></a>
<a name="line-87"></a><span class='comment'>-- | enumerate all chars specified by a predicate</span>
<a name="line-88"></a><span class='comment'>--</span>
<a name="line-89"></a><span class='comment'>-- this function is expensive, it should only be used for testing</span>
<a name="line-90"></a>
<a name="line-91"></a><a name="chars"></a><span class='definition'>chars</span> <span class='keyglyph'>::</span> <span class='layout'>(</span><span class='conid'>Char</span> <span class='keyglyph'>-></span> <span class='conid'>Bool</span><span class='layout'>)</span> <span class='keyglyph'>-></span> <span class='keyglyph'>[</span><span class='conid'>Char</span><span class='keyglyph'>]</span>
<a name="line-92"></a><span class='definition'>chars</span> <span class='varid'>p</span> <span class='keyglyph'>=</span> <span class='varid'>filter</span> <span class='varid'>p</span> <span class='varop'>$</span> <span class='keyglyph'>[</span><span class='varid'>minBound</span> <span class='keyglyph'>..</span> <span class='varid'>maxBound</span><span class='keyglyph'>]</span>
<a name="line-93"></a>
<a name="line-94"></a><a name="charRngs"></a><span class='definition'>charRngs</span> <span class='keyglyph'>::</span> <span class='keyglyph'>[</span><span class='conid'>Char</span><span class='keyglyph'>]</span> <span class='keyglyph'>-></span> <span class='keyglyph'>[</span><span class='layout'>(</span><span class='conid'>Char</span><span class='layout'>,</span> <span class='conid'>Char</span><span class='layout'>)</span><span class='keyglyph'>]</span>
<a name="line-95"></a><span class='definition'>charRngs</span> <span class='conid'>[]</span> <span class='keyglyph'>=</span> <span class='conid'>[]</span>
<a name="line-96"></a><span class='definition'>charRngs</span> <span class='layout'>(</span><span class='varid'>x</span><span class='conop'>:</span><span class='varid'>xs</span><span class='layout'>)</span> <span class='keyglyph'>=</span> <span class='varid'>charRng</span> <span class='varid'>x</span> <span class='varid'>xs</span>
<a name="line-97"></a> <span class='keyword'>where</span>
<a name="line-98"></a> <span class='varid'>charRng</span> <span class='varid'>y</span> <span class='conid'>[]</span> <span class='keyglyph'>=</span> <span class='layout'>(</span><span class='varid'>x</span><span class='layout'>,</span><span class='varid'>y</span><span class='layout'>)</span> <span class='conop'>:</span> <span class='conid'>[]</span>
<a name="line-99"></a> <span class='varid'>charRng</span> <span class='varid'>y</span> <span class='varid'>xs'</span><span class='keyglyph'>@</span><span class='layout'>(</span><span class='varid'>x1</span><span class='conop'>:</span><span class='varid'>xs1</span><span class='layout'>)</span>
<a name="line-100"></a> <span class='keyglyph'>|</span> <span class='varid'>x1</span> <span class='varop'>==</span> <span class='varid'>succ</span> <span class='varid'>y</span> <span class='keyglyph'>=</span> <span class='varid'>charRng</span> <span class='varid'>x1</span> <span class='varid'>xs1</span>
<a name="line-101"></a> <span class='keyglyph'>|</span> <span class='varid'>otherwise</span> <span class='keyglyph'>=</span> <span class='layout'>(</span><span class='varid'>x</span><span class='layout'>,</span><span class='varid'>y</span><span class='layout'>)</span> <span class='conop'>:</span> <span class='varid'>charRngs</span> <span class='varid'>xs'</span>
<a name="line-102"></a>
<a name="line-103"></a><a name="mkZero"></a><span class='definition'>mkZero</span> <span class='keyglyph'>::</span> <span class='conid'>String</span> <span class='keyglyph'>-></span> <span class='conid'>Regex</span>
<a name="line-104"></a><span class='definition'>mkZero</span> <span class='keyglyph'>=</span> <span class='conid'>Zero</span>
<a name="line-105"></a>
<a name="line-106"></a><a name="mkUnit"></a><span class='definition'>mkUnit</span> <span class='keyglyph'>::</span> <span class='conid'>Regex</span>
<a name="line-107"></a><span class='definition'>mkUnit</span> <span class='keyglyph'>=</span> <span class='conid'>Unit</span>
<a name="line-108"></a>
<a name="line-109"></a><a name="mkSym"></a><span class='definition'>mkSym</span> <span class='keyglyph'>::</span> <span class='layout'>(</span><span class='conid'>Char</span> <span class='keyglyph'>-></span> <span class='conid'>Bool</span><span class='layout'>)</span> <span class='keyglyph'>-></span> <span class='conid'>Regex</span>
<a name="line-110"></a><span class='definition'>mkSym</span> <span class='keyglyph'>=</span> <span class='conid'>Sym</span>
<a name="line-111"></a>
<a name="line-112"></a><a name="mkSym1"></a><span class='definition'>mkSym1</span> <span class='keyglyph'>::</span> <span class='conid'>Char</span> <span class='keyglyph'>-></span> <span class='conid'>Regex</span>
<a name="line-113"></a><span class='definition'>mkSym1</span> <span class='varid'>c</span> <span class='keyglyph'>=</span> <span class='varid'>mkSym</span> <span class='layout'>(</span><span class='varop'>==</span><span class='varid'>c</span><span class='layout'>)</span>
<a name="line-114"></a>
<a name="line-115"></a><a name="mkSymRng"></a><span class='definition'>mkSymRng</span> <span class='keyglyph'>::</span> <span class='conid'>Char</span> <span class='keyglyph'>-></span> <span class='conid'>Char</span> <span class='keyglyph'>-></span> <span class='conid'>Regex</span>
<a name="line-116"></a><span class='definition'>mkSymRng</span> <span class='varid'>c1</span> <span class='varid'>c2</span>
<a name="line-117"></a> <span class='keyglyph'>|</span> <span class='varid'>c1</span> <span class='varop'>==</span> <span class='varid'>minBound</span> <span class='varop'>&&</span>
<a name="line-118"></a> <span class='varid'>c2</span> <span class='varop'>==</span> <span class='varid'>maxBound</span> <span class='keyglyph'>=</span> <span class='varid'>mkDot</span>
<a name="line-119"></a> <span class='keyglyph'>|</span> <span class='varid'>c1</span> <span class='varop'><=</span> <span class='varid'>c2</span> <span class='keyglyph'>=</span> <span class='varid'>mkSym</span> <span class='varop'>$</span> <span class='layout'>(</span> <span class='keyglyph'>\</span> <span class='varid'>x</span> <span class='keyglyph'>-></span> <span class='varid'>x</span> <span class='varop'>>=</span> <span class='varid'>c1</span> <span class='varop'>&&</span> <span class='varid'>x</span><span class='varop'><=</span> <span class='varid'>c2</span> <span class='layout'>)</span>
<a name="line-120"></a> <span class='keyglyph'>|</span> <span class='varid'>otherwise</span> <span class='keyglyph'>=</span> <span class='varid'>mkZero</span> <span class='varop'>$</span> <span class='str'>"empty char range"</span>
<a name="line-121"></a>
<a name="line-122"></a><a name="mkDot"></a><span class='definition'>mkDot</span> <span class='keyglyph'>::</span> <span class='conid'>Regex</span>
<a name="line-123"></a><span class='definition'>mkDot</span> <span class='keyglyph'>=</span> <span class='conid'>Dot</span>
<a name="line-124"></a>
<a name="line-125"></a><a name="mkStar"></a><span class='definition'>mkStar</span> <span class='keyglyph'>::</span> <span class='conid'>Regex</span> <span class='keyglyph'>-></span> <span class='conid'>Regex</span>
<a name="line-126"></a><span class='definition'>mkStar</span> <span class='layout'>(</span><span class='conid'>Zero</span> <span class='keyword'>_</span><span class='layout'>)</span> <span class='keyglyph'>=</span> <span class='varid'>mkUnit</span> <span class='comment'>-- {}* == ()</span>
<a name="line-127"></a><span class='definition'>mkStar</span> <span class='varid'>e</span><span class='keyglyph'>@</span><span class='conid'>Unit</span> <span class='keyglyph'>=</span> <span class='varid'>e</span> <span class='comment'>-- ()* == ()</span>
<a name="line-128"></a><span class='definition'>mkStar</span> <span class='varid'>e</span><span class='keyglyph'>@</span><span class='layout'>(</span><span class='conid'>Star</span> <span class='sel'>_e1</span><span class='layout'>)</span> <span class='keyglyph'>=</span> <span class='varid'>e</span> <span class='comment'>-- (r*)* == r*</span>
<a name="line-129"></a><span class='definition'>mkStar</span> <span class='layout'>(</span><span class='conid'>Rep</span> <span class='num'>1</span> <span class='varid'>e1</span><span class='layout'>)</span> <span class='keyglyph'>=</span> <span class='varid'>mkStar</span> <span class='varid'>e1</span> <span class='comment'>-- (r+)* == r*</span>
<a name="line-130"></a><span class='definition'>mkStar</span> <span class='varid'>e</span><span class='keyglyph'>@</span><span class='layout'>(</span><span class='conid'>Alt</span> <span class='keyword'>_</span> <span class='keyword'>_</span><span class='layout'>)</span> <span class='keyglyph'>=</span> <span class='conid'>Star</span> <span class='layout'>(</span><span class='varid'>rmStar</span> <span class='varid'>e</span><span class='layout'>)</span> <span class='comment'>-- (a*|b)* == (a|b)*</span>
<a name="line-131"></a><span class='definition'>mkStar</span> <span class='varid'>e</span> <span class='keyglyph'>=</span> <span class='conid'>Star</span> <span class='varid'>e</span>
<a name="line-132"></a>
<a name="line-133"></a><a name="rmStar"></a><span class='definition'>rmStar</span> <span class='keyglyph'>::</span> <span class='conid'>Regex</span> <span class='keyglyph'>-></span> <span class='conid'>Regex</span>
<a name="line-134"></a><span class='definition'>rmStar</span> <span class='layout'>(</span><span class='conid'>Alt</span> <span class='varid'>e1</span> <span class='varid'>e2</span><span class='layout'>)</span> <span class='keyglyph'>=</span> <span class='varid'>mkAlt</span> <span class='layout'>(</span><span class='varid'>rmStar</span> <span class='varid'>e1</span><span class='layout'>)</span> <span class='layout'>(</span><span class='varid'>rmStar</span> <span class='varid'>e2</span><span class='layout'>)</span>
<a name="line-135"></a><span class='definition'>rmStar</span> <span class='layout'>(</span><span class='conid'>Star</span> <span class='varid'>e1</span><span class='layout'>)</span> <span class='keyglyph'>=</span> <span class='varid'>rmStar</span> <span class='varid'>e1</span>
<a name="line-136"></a><span class='definition'>rmStar</span> <span class='layout'>(</span><span class='conid'>Rep</span> <span class='num'>1</span> <span class='varid'>e1</span><span class='layout'>)</span> <span class='keyglyph'>=</span> <span class='varid'>rmStar</span> <span class='varid'>e1</span>
<a name="line-137"></a><span class='definition'>rmStar</span> <span class='varid'>e1</span> <span class='keyglyph'>=</span> <span class='varid'>e1</span>
<a name="line-138"></a>
<a name="line-139"></a><a name="mkAlt"></a><span class='definition'>mkAlt</span> <span class='keyglyph'>::</span> <span class='conid'>Regex</span> <span class='keyglyph'>-></span> <span class='conid'>Regex</span> <span class='keyglyph'>-></span> <span class='conid'>Regex</span>
<a name="line-140"></a><span class='definition'>mkAlt</span> <span class='varid'>e1</span> <span class='layout'>(</span><span class='conid'>Zero</span> <span class='keyword'>_</span><span class='layout'>)</span> <span class='keyglyph'>=</span> <span class='varid'>e1</span> <span class='comment'>-- e1 u {} = e1</span>
<a name="line-141"></a><span class='definition'>mkAlt</span> <span class='layout'>(</span><span class='conid'>Zero</span> <span class='keyword'>_</span><span class='layout'>)</span> <span class='varid'>e2</span> <span class='keyglyph'>=</span> <span class='varid'>e2</span> <span class='comment'>-- {} u e2 = e2</span>
<a name="line-142"></a><span class='definition'>mkAlt</span> <span class='varid'>e1</span><span class='keyglyph'>@</span><span class='layout'>(</span><span class='conid'>Star</span> <span class='conid'>Dot</span><span class='layout'>)</span> <span class='sel'>_e2</span> <span class='keyglyph'>=</span> <span class='varid'>e1</span> <span class='comment'>-- A* u e1 = A*</span>
<a name="line-143"></a><span class='definition'>mkAlt</span> <span class='sel'>_e1</span> <span class='varid'>e2</span><span class='keyglyph'>@</span><span class='layout'>(</span><span class='conid'>Star</span> <span class='conid'>Dot</span><span class='layout'>)</span> <span class='keyglyph'>=</span> <span class='varid'>e2</span> <span class='comment'>-- e1 u A* = A*</span>
<a name="line-144"></a><span class='definition'>mkAlt</span> <span class='layout'>(</span><span class='conid'>Sym</span> <span class='varid'>p1</span><span class='layout'>)</span> <span class='layout'>(</span><span class='conid'>Sym</span> <span class='varid'>p2</span><span class='layout'>)</span> <span class='keyglyph'>=</span> <span class='varid'>mkSym</span> <span class='varop'>$</span> <span class='keyglyph'>\</span> <span class='varid'>x</span> <span class='keyglyph'>-></span> <span class='varid'>p1</span> <span class='varid'>x</span> <span class='varop'>||</span> <span class='varid'>p2</span> <span class='varid'>x</span> <span class='comment'>-- melting of predicates</span>
<a name="line-145"></a><span class='definition'>mkAlt</span> <span class='varid'>e1</span> <span class='varid'>e2</span><span class='keyglyph'>@</span><span class='layout'>(</span><span class='conid'>Sym</span> <span class='keyword'>_</span><span class='layout'>)</span> <span class='keyglyph'>=</span> <span class='varid'>mkAlt</span> <span class='varid'>e2</span> <span class='varid'>e1</span> <span class='comment'>-- symmetry: predicates always first</span>
<a name="line-146"></a><span class='definition'>mkAlt</span> <span class='varid'>e1</span><span class='keyglyph'>@</span><span class='layout'>(</span><span class='conid'>Sym</span> <span class='keyword'>_</span><span class='layout'>)</span> <span class='layout'>(</span><span class='conid'>Alt</span> <span class='varid'>e2</span><span class='keyglyph'>@</span><span class='layout'>(</span><span class='conid'>Sym</span> <span class='keyword'>_</span><span class='layout'>)</span> <span class='varid'>e3</span><span class='layout'>)</span> <span class='keyglyph'>=</span> <span class='varid'>mkAlt</span> <span class='layout'>(</span><span class='varid'>mkAlt</span> <span class='varid'>e1</span> <span class='varid'>e2</span><span class='layout'>)</span> <span class='varid'>e3</span> <span class='comment'>-- prepare melting of predicates</span>
<a name="line-147"></a><span class='definition'>mkAlt</span> <span class='layout'>(</span><span class='conid'>Alt</span> <span class='varid'>e1</span> <span class='varid'>e2</span><span class='layout'>)</span> <span class='varid'>e3</span> <span class='keyglyph'>=</span> <span class='varid'>mkAlt</span> <span class='varid'>e1</span> <span class='layout'>(</span><span class='varid'>mkAlt</span> <span class='varid'>e2</span> <span class='varid'>e3</span><span class='layout'>)</span> <span class='comment'>-- associativity</span>
<a name="line-148"></a><span class='definition'>mkAlt</span> <span class='varid'>e1</span> <span class='varid'>e2</span> <span class='keyglyph'>=</span> <span class='conid'>Alt</span> <span class='varid'>e1</span> <span class='varid'>e2</span>
<a name="line-149"></a>
<a name="line-150"></a><a name="mkSeq"></a><span class='definition'>mkSeq</span> <span class='keyglyph'>::</span> <span class='conid'>Regex</span> <span class='keyglyph'>-></span> <span class='conid'>Regex</span> <span class='keyglyph'>-></span> <span class='conid'>Regex</span>
<a name="line-151"></a><span class='definition'>mkSeq</span> <span class='varid'>e1</span><span class='keyglyph'>@</span><span class='layout'>(</span><span class='conid'>Zero</span> <span class='keyword'>_</span><span class='layout'>)</span> <span class='sel'>_e2</span> <span class='keyglyph'>=</span> <span class='varid'>e1</span>
<a name="line-152"></a><span class='definition'>mkSeq</span> <span class='sel'>_e1</span> <span class='varid'>e2</span><span class='keyglyph'>@</span><span class='layout'>(</span><span class='conid'>Zero</span> <span class='keyword'>_</span><span class='layout'>)</span> <span class='keyglyph'>=</span> <span class='varid'>e2</span>
<a name="line-153"></a><span class='definition'>mkSeq</span> <span class='conid'>Unit</span> <span class='varid'>e2</span> <span class='keyglyph'>=</span> <span class='varid'>e2</span>
<a name="line-154"></a><span class='definition'>mkSeq</span> <span class='varid'>e1</span> <span class='conid'>Unit</span> <span class='keyglyph'>=</span> <span class='varid'>e1</span>
<a name="line-155"></a><span class='definition'>mkSeq</span> <span class='layout'>(</span><span class='conid'>Seq</span> <span class='varid'>e1</span> <span class='varid'>e2</span><span class='layout'>)</span> <span class='varid'>e3</span> <span class='keyglyph'>=</span> <span class='varid'>mkSeq</span> <span class='varid'>e1</span> <span class='layout'>(</span><span class='varid'>mkSeq</span> <span class='varid'>e2</span> <span class='varid'>e3</span><span class='layout'>)</span>
<a name="line-156"></a><span class='definition'>mkSeq</span> <span class='varid'>e1</span> <span class='varid'>e2</span> <span class='keyglyph'>=</span> <span class='conid'>Seq</span> <span class='varid'>e1</span> <span class='varid'>e2</span>
<a name="line-157"></a>
<a name="line-158"></a><a name="mkRep"></a><span class='definition'>mkRep</span> <span class='keyglyph'>::</span> <span class='conid'>Int</span> <span class='keyglyph'>-></span> <span class='conid'>Regex</span> <span class='keyglyph'>-></span> <span class='conid'>Regex</span>
<a name="line-159"></a><span class='definition'>mkRep</span> <span class='num'>0</span> <span class='varid'>e</span> <span class='keyglyph'>=</span> <span class='varid'>mkStar</span> <span class='varid'>e</span>
<a name="line-160"></a><span class='definition'>mkRep</span> <span class='keyword'>_</span> <span class='varid'>e</span><span class='keyglyph'>@</span><span class='layout'>(</span><span class='conid'>Zero</span> <span class='keyword'>_</span><span class='layout'>)</span> <span class='keyglyph'>=</span> <span class='varid'>e</span>
<a name="line-161"></a><span class='definition'>mkRep</span> <span class='keyword'>_</span> <span class='varid'>e</span><span class='keyglyph'>@</span><span class='conid'>Unit</span> <span class='keyglyph'>=</span> <span class='varid'>e</span>
<a name="line-162"></a><span class='definition'>mkRep</span> <span class='varid'>i</span> <span class='varid'>e</span> <span class='keyglyph'>=</span> <span class='conid'>Rep</span> <span class='varid'>i</span> <span class='varid'>e</span>
<a name="line-163"></a>
<a name="line-164"></a><a name="mkRng"></a><span class='definition'>mkRng</span> <span class='keyglyph'>::</span> <span class='conid'>Int</span> <span class='keyglyph'>-></span> <span class='conid'>Int</span> <span class='keyglyph'>-></span> <span class='conid'>Regex</span> <span class='keyglyph'>-></span> <span class='conid'>Regex</span>
<a name="line-165"></a><span class='definition'>mkRng</span> <span class='num'>0</span> <span class='num'>0</span> <span class='sel'>_e</span> <span class='keyglyph'>=</span> <span class='varid'>mkUnit</span>
<a name="line-166"></a><span class='definition'>mkRng</span> <span class='num'>1</span> <span class='num'>1</span> <span class='varid'>e</span> <span class='keyglyph'>=</span> <span class='varid'>e</span>
<a name="line-167"></a><span class='definition'>mkRng</span> <span class='varid'>lb</span> <span class='varid'>ub</span> <span class='sel'>_e</span>
<a name="line-168"></a> <span class='keyglyph'>|</span> <span class='varid'>lb</span> <span class='varop'>></span> <span class='varid'>ub</span> <span class='keyglyph'>=</span> <span class='conid'>Zero</span> <span class='varop'>$</span>
<a name="line-169"></a> <span class='str'>"illegal range "</span> <span class='varop'>++</span>
<a name="line-170"></a> <span class='varid'>show</span> <span class='varid'>lb</span> <span class='varop'>++</span> <span class='str'>".."</span> <span class='varop'>++</span> <span class='varid'>show</span> <span class='varid'>ub</span>
<a name="line-171"></a><span class='definition'>mkRng</span> <span class='sel'>_l</span> <span class='sel'>_u</span> <span class='varid'>e</span><span class='keyglyph'>@</span><span class='layout'>(</span><span class='conid'>Zero</span> <span class='keyword'>_</span><span class='layout'>)</span> <span class='keyglyph'>=</span> <span class='varid'>e</span>
<a name="line-172"></a><span class='definition'>mkRng</span> <span class='sel'>_l</span> <span class='sel'>_u</span> <span class='varid'>e</span><span class='keyglyph'>@</span><span class='conid'>Unit</span> <span class='keyglyph'>=</span> <span class='varid'>e</span>
<a name="line-173"></a><span class='definition'>mkRng</span> <span class='varid'>lb</span> <span class='varid'>ub</span> <span class='varid'>e</span> <span class='keyglyph'>=</span> <span class='conid'>Rng</span> <span class='varid'>lb</span> <span class='varid'>ub</span> <span class='varid'>e</span>
<a name="line-174"></a>
<a name="line-175"></a><a name="mkOpt"></a><span class='definition'>mkOpt</span> <span class='keyglyph'>::</span> <span class='conid'>Regex</span> <span class='keyglyph'>-></span> <span class='conid'>Regex</span>
<a name="line-176"></a><span class='definition'>mkOpt</span> <span class='keyglyph'>=</span> <span class='varid'>mkRng</span> <span class='num'>0</span> <span class='num'>1</span>
<a name="line-177"></a>
<a name="line-178"></a><a name="mkDif"></a><span class='definition'>mkDif</span> <span class='keyglyph'>::</span> <span class='conid'>Regex</span> <span class='keyglyph'>-></span> <span class='conid'>Regex</span> <span class='keyglyph'>-></span> <span class='conid'>Regex</span>
<a name="line-179"></a><span class='definition'>mkDif</span> <span class='varid'>e1</span><span class='keyglyph'>@</span><span class='layout'>(</span><span class='conid'>Zero</span> <span class='keyword'>_</span><span class='layout'>)</span> <span class='sel'>_e2</span> <span class='keyglyph'>=</span> <span class='varid'>e1</span>
<a name="line-180"></a><span class='definition'>mkDif</span> <span class='varid'>e1</span> <span class='layout'>(</span><span class='conid'>Zero</span> <span class='keyword'>_</span><span class='layout'>)</span> <span class='keyglyph'>=</span> <span class='varid'>e1</span>
<a name="line-181"></a><span class='definition'>mkDif</span> <span class='sel'>_e1</span> <span class='layout'>(</span><span class='conid'>Star</span> <span class='conid'>Dot</span><span class='layout'>)</span> <span class='keyglyph'>=</span> <span class='varid'>mkZero</span> <span class='str'>"empty set in difference expr"</span>
<a name="line-182"></a><span class='definition'>mkDif</span> <span class='conid'>Dot</span> <span class='layout'>(</span><span class='conid'>Sym</span> <span class='varid'>p</span><span class='layout'>)</span> <span class='keyglyph'>=</span> <span class='varid'>mkSym</span> <span class='layout'>(</span><span class='varid'>not</span> <span class='varop'>.</span> <span class='varid'>p</span><span class='layout'>)</span>
<a name="line-183"></a><span class='definition'>mkDif</span> <span class='layout'>(</span><span class='conid'>Sym</span> <span class='keyword'>_</span><span class='layout'>)</span> <span class='conid'>Dot</span> <span class='keyglyph'>=</span> <span class='varid'>mkZero</span> <span class='str'>"empty set of chars in difference expr"</span>
<a name="line-184"></a><span class='definition'>mkDif</span> <span class='layout'>(</span><span class='conid'>Sym</span> <span class='varid'>p1</span><span class='layout'>)</span> <span class='layout'>(</span><span class='conid'>Sym</span> <span class='varid'>p2</span><span class='layout'>)</span>
<a name="line-185"></a> <span class='keyglyph'>|</span> <span class='varid'>null</span> <span class='varop'>.</span> <span class='varid'>chars</span> <span class='varop'>$</span> <span class='layout'>(</span><span class='keyglyph'>\</span> <span class='varid'>x</span> <span class='keyglyph'>-></span> <span class='varid'>p1</span> <span class='varid'>x</span> <span class='varop'>&&</span> <span class='varid'>not</span> <span class='layout'>(</span><span class='varid'>p2</span> <span class='varid'>x</span><span class='layout'>)</span><span class='layout'>)</span>
<a name="line-186"></a> <span class='keyglyph'>=</span> <span class='varid'>mkZero</span> <span class='str'>"empty set of chars in difference expr"</span>
<a name="line-187"></a><span class='definition'>mkDif</span> <span class='varid'>e1</span> <span class='varid'>e2</span> <span class='keyglyph'>=</span> <span class='conid'>Dif</span> <span class='varid'>e1</span> <span class='varid'>e2</span>
<a name="line-188"></a>
<a name="line-189"></a><a name="mkCompl"></a><span class='definition'>mkCompl</span> <span class='keyglyph'>::</span> <span class='conid'>Regex</span> <span class='keyglyph'>-></span> <span class='conid'>Regex</span>
<a name="line-190"></a><span class='definition'>mkCompl</span> <span class='keyglyph'>=</span> <span class='varid'>mkDif</span> <span class='varid'>mkDot</span>
<a name="line-191"></a>
<a name="line-192"></a><span class='comment'>-- ------------------------------------------------------------</span>
<a name="line-193"></a>
<a name="line-194"></a><span class='keyword'>instance</span> <span class='conid'>Show</span> <span class='conid'>Regex</span> <span class='keyword'>where</span>
<a name="line-195"></a> <span class='varid'>show</span> <span class='layout'>(</span><span class='conid'>Zero</span> <span class='varid'>s</span><span class='layout'>)</span> <span class='keyglyph'>=</span> <span class='str'>"{err:"</span> <span class='varop'>++</span> <span class='varid'>s</span> <span class='varop'>++</span> <span class='str'>"}"</span>
<a name="line-196"></a> <span class='varid'>show</span> <span class='conid'>Unit</span> <span class='keyglyph'>=</span> <span class='str'>"()"</span>
<a name="line-197"></a> <span class='varid'>show</span> <span class='layout'>(</span><span class='conid'>Sym</span> <span class='varid'>p</span><span class='layout'>)</span>
<a name="line-198"></a> <span class='keyglyph'>|</span> <span class='varid'>null</span> <span class='layout'>(</span><span class='varid'>tail</span> <span class='varid'>cs</span><span class='layout'>)</span> <span class='varop'>&&</span>
<a name="line-199"></a> <span class='varid'>rng1</span> <span class='layout'>(</span><span class='varid'>head</span> <span class='varid'>cs</span><span class='layout'>)</span>
<a name="line-200"></a> <span class='keyglyph'>=</span> <span class='varid'>escRng</span> <span class='varop'>.</span> <span class='varid'>head</span> <span class='varop'>$</span> <span class='varid'>cs</span>
<a name="line-201"></a> <span class='keyglyph'>|</span> <span class='varid'>otherwise</span> <span class='keyglyph'>=</span> <span class='str'>"["</span> <span class='varop'>++</span> <span class='varid'>concat</span> <span class='varid'>cs'</span> <span class='varop'>++</span> <span class='str'>"]"</span>
<a name="line-202"></a> <span class='keyword'>where</span>
<a name="line-203"></a> <span class='varid'>rng1</span> <span class='layout'>(</span><span class='varid'>x</span><span class='layout'>,</span><span class='varid'>y</span><span class='layout'>)</span> <span class='keyglyph'>=</span> <span class='varid'>x</span> <span class='varop'>==</span> <span class='varid'>y</span>
<a name="line-204"></a> <span class='varid'>cs</span> <span class='keyglyph'>=</span> <span class='varid'>charRngs</span> <span class='varop'>.</span> <span class='varid'>chars</span> <span class='varop'>$</span> <span class='varid'>p</span>
<a name="line-205"></a> <span class='varid'>cs'</span> <span class='keyglyph'>=</span> <span class='varid'>map</span> <span class='varid'>escRng</span> <span class='varid'>cs</span>
<a name="line-206"></a> <span class='varid'>escRng</span> <span class='layout'>(</span><span class='varid'>x</span><span class='layout'>,</span> <span class='varid'>y</span><span class='layout'>)</span>
<a name="line-207"></a> <span class='keyglyph'>|</span> <span class='varid'>x</span> <span class='varop'>==</span> <span class='varid'>y</span> <span class='keyglyph'>=</span> <span class='varid'>esc</span> <span class='varid'>x</span>
<a name="line-208"></a> <span class='keyglyph'>|</span> <span class='varid'>succ</span> <span class='varid'>x</span> <span class='varop'>==</span> <span class='varid'>y</span>
<a name="line-209"></a> <span class='keyglyph'>=</span> <span class='varid'>esc</span> <span class='varid'>x</span> <span class='varop'>++</span> <span class='varid'>esc</span> <span class='varid'>y</span>
<a name="line-210"></a> <span class='keyglyph'>|</span> <span class='varid'>otherwise</span>
<a name="line-211"></a> <span class='keyglyph'>=</span> <span class='varid'>esc</span> <span class='varid'>x</span> <span class='varop'>++</span> <span class='str'>"-"</span> <span class='varop'>++</span> <span class='varid'>esc</span> <span class='varid'>y</span>
<a name="line-212"></a> <span class='varid'>esc</span> <span class='varid'>x</span>
<a name="line-213"></a> <span class='keyglyph'>|</span> <span class='varid'>x</span> <span class='varop'>`elem`</span> <span class='str'>"\\-[]{}()*+?.^"</span>
<a name="line-214"></a> <span class='keyglyph'>=</span> <span class='chr'>'\\'</span><span class='conop'>:</span><span class='varid'>x</span><span class='conop'>:</span><span class='str'>""</span>
<a name="line-215"></a> <span class='keyglyph'>|</span> <span class='varid'>x</span> <span class='varop'>>=</span> <span class='chr'>' '</span> <span class='varop'>&&</span> <span class='varid'>x</span> <span class='varop'><=</span> <span class='chr'>'~'</span>
<a name="line-216"></a> <span class='keyglyph'>=</span> <span class='varid'>x</span><span class='conop'>:</span><span class='str'>""</span>
<a name="line-217"></a> <span class='keyglyph'>|</span> <span class='varid'>otherwise</span>
<a name="line-218"></a> <span class='keyglyph'>=</span> <span class='str'>"&#"</span> <span class='varop'>++</span> <span class='varid'>show</span> <span class='layout'>(</span><span class='varid'>fromEnum</span> <span class='varid'>x</span><span class='layout'>)</span> <span class='varop'>++</span> <span class='str'>";"</span>
<a name="line-219"></a> <span class='varid'>show</span> <span class='conid'>Dot</span> <span class='keyglyph'>=</span> <span class='str'>"."</span>
<a name="line-220"></a> <span class='varid'>show</span> <span class='layout'>(</span><span class='conid'>Star</span> <span class='varid'>e</span><span class='layout'>)</span> <span class='keyglyph'>=</span> <span class='str'>"("</span> <span class='varop'>++</span> <span class='varid'>show</span> <span class='varid'>e</span> <span class='varop'>++</span> <span class='str'>")*"</span>
<a name="line-221"></a> <span class='varid'>show</span> <span class='layout'>(</span><span class='conid'>Alt</span> <span class='varid'>e1</span> <span class='varid'>e2</span><span class='layout'>)</span> <span class='keyglyph'>=</span> <span class='str'>"("</span> <span class='varop'>++</span> <span class='varid'>show</span> <span class='varid'>e1</span> <span class='varop'>++</span> <span class='str'>"|"</span> <span class='varop'>++</span> <span class='varid'>show</span> <span class='varid'>e2</span> <span class='varop'>++</span> <span class='str'>")"</span>
<a name="line-222"></a> <span class='varid'>show</span> <span class='layout'>(</span><span class='conid'>Seq</span> <span class='varid'>e1</span> <span class='varid'>e2</span><span class='layout'>)</span> <span class='keyglyph'>=</span> <span class='varid'>show</span> <span class='varid'>e1</span> <span class='varop'>++</span> <span class='varid'>show</span> <span class='varid'>e2</span>
<a name="line-223"></a> <span class='varid'>show</span> <span class='layout'>(</span><span class='conid'>Rep</span> <span class='num'>1</span> <span class='varid'>e</span><span class='layout'>)</span> <span class='keyglyph'>=</span> <span class='str'>"("</span> <span class='varop'>++</span> <span class='varid'>show</span> <span class='varid'>e</span> <span class='varop'>++</span> <span class='str'>")+"</span>
<a name="line-224"></a> <span class='varid'>show</span> <span class='layout'>(</span><span class='conid'>Rep</span> <span class='varid'>i</span> <span class='varid'>e</span><span class='layout'>)</span> <span class='keyglyph'>=</span> <span class='str'>"("</span> <span class='varop'>++</span> <span class='varid'>show</span> <span class='varid'>e</span> <span class='varop'>++</span> <span class='str'>"){"</span> <span class='varop'>++</span> <span class='varid'>show</span> <span class='varid'>i</span> <span class='varop'>++</span> <span class='str'>",}"</span>
<a name="line-225"></a> <span class='varid'>show</span> <span class='layout'>(</span><span class='conid'>Rng</span> <span class='num'>0</span> <span class='num'>1</span> <span class='varid'>e</span><span class='layout'>)</span> <span class='keyglyph'>=</span> <span class='str'>"("</span> <span class='varop'>++</span> <span class='varid'>show</span> <span class='varid'>e</span> <span class='varop'>++</span> <span class='str'>")?"</span>
<a name="line-226"></a> <span class='varid'>show</span> <span class='layout'>(</span><span class='conid'>Rng</span> <span class='varid'>i</span> <span class='varid'>j</span> <span class='varid'>e</span><span class='layout'>)</span> <span class='keyglyph'>=</span> <span class='str'>"("</span> <span class='varop'>++</span> <span class='varid'>show</span> <span class='varid'>e</span> <span class='varop'>++</span> <span class='str'>"){"</span> <span class='varop'>++</span> <span class='varid'>show</span> <span class='varid'>i</span> <span class='varop'>++</span> <span class='str'>","</span> <span class='varop'>++</span> <span class='varid'>show</span> <span class='varid'>j</span> <span class='varop'>++</span> <span class='str'>"}"</span>
<a name="line-227"></a> <span class='varid'>show</span> <span class='layout'>(</span><span class='conid'>Dif</span> <span class='varid'>e1</span> <span class='varid'>e2</span><span class='layout'>)</span> <span class='keyglyph'>=</span> <span class='str'>"("</span> <span class='varop'>++</span> <span class='varid'>show</span> <span class='varid'>e1</span> <span class='varop'>++</span> <span class='str'>"-"</span> <span class='varop'>++</span> <span class='varid'>show</span> <span class='varid'>e2</span> <span class='varop'>++</span> <span class='str'>")"</span>
<a name="line-228"></a>
<a name="line-229"></a><span class='comment'>-- ------------------------------------------------------------</span>
<a name="line-230"></a>
<a name="line-231"></a><a name="isZero"></a><span class='definition'>isZero</span> <span class='keyglyph'>::</span> <span class='conid'>Regex</span> <span class='keyglyph'>-></span> <span class='conid'>Bool</span>
<a name="line-232"></a><span class='definition'>isZero</span> <span class='layout'>(</span><span class='conid'>Zero</span> <span class='keyword'>_</span><span class='layout'>)</span> <span class='keyglyph'>=</span> <span class='conid'>True</span>
<a name="line-233"></a><span class='definition'>isZero</span> <span class='keyword'>_</span> <span class='keyglyph'>=</span> <span class='conid'>False</span>
<a name="line-234"></a>
<a name="line-235"></a><a name="nullable"></a><span class='definition'>nullable</span> <span class='keyglyph'>::</span> <span class='conid'>Regex</span> <span class='keyglyph'>-></span> <span class='conid'>Bool</span>
<a name="line-236"></a><span class='definition'>nullable</span> <span class='layout'>(</span><span class='conid'>Zero</span> <span class='keyword'>_</span><span class='layout'>)</span> <span class='keyglyph'>=</span> <span class='conid'>False</span>
<a name="line-237"></a><span class='definition'>nullable</span> <span class='conid'>Unit</span> <span class='keyglyph'>=</span> <span class='conid'>True</span>
<a name="line-238"></a><span class='definition'>nullable</span> <span class='layout'>(</span><span class='conid'>Sym</span> <span class='sel'>_p</span><span class='layout'>)</span> <span class='keyglyph'>=</span> <span class='conid'>False</span> <span class='comment'>-- assumption: p holds for at least one char</span>
<a name="line-239"></a><span class='definition'>nullable</span> <span class='conid'>Dot</span> <span class='keyglyph'>=</span> <span class='conid'>False</span>
<a name="line-240"></a><span class='definition'>nullable</span> <span class='layout'>(</span><span class='conid'>Star</span> <span class='keyword'>_</span><span class='layout'>)</span> <span class='keyglyph'>=</span> <span class='conid'>True</span>
<a name="line-241"></a><span class='definition'>nullable</span> <span class='layout'>(</span><span class='conid'>Alt</span> <span class='varid'>e1</span> <span class='varid'>e2</span><span class='layout'>)</span> <span class='keyglyph'>=</span> <span class='varid'>nullable</span> <span class='varid'>e1</span> <span class='varop'>||</span>
<a name="line-242"></a> <span class='varid'>nullable</span> <span class='varid'>e2</span>
<a name="line-243"></a><span class='definition'>nullable</span> <span class='layout'>(</span><span class='conid'>Seq</span> <span class='varid'>e1</span> <span class='varid'>e2</span><span class='layout'>)</span> <span class='keyglyph'>=</span> <span class='varid'>nullable</span> <span class='varid'>e1</span> <span class='varop'>&&</span>
<a name="line-244"></a> <span class='varid'>nullable</span> <span class='varid'>e2</span>
<a name="line-245"></a><span class='definition'>nullable</span> <span class='layout'>(</span><span class='conid'>Rep</span> <span class='sel'>_i</span> <span class='varid'>e</span><span class='layout'>)</span> <span class='keyglyph'>=</span> <span class='varid'>nullable</span> <span class='varid'>e</span>
<a name="line-246"></a><span class='definition'>nullable</span> <span class='layout'>(</span><span class='conid'>Rng</span> <span class='varid'>i</span> <span class='keyword'>_</span> <span class='varid'>e</span><span class='layout'>)</span> <span class='keyglyph'>=</span> <span class='varid'>i</span> <span class='varop'>==</span> <span class='num'>0</span> <span class='varop'>||</span>
<a name="line-247"></a> <span class='varid'>nullable</span> <span class='varid'>e</span>
<a name="line-248"></a><span class='definition'>nullable</span> <span class='layout'>(</span><span class='conid'>Dif</span> <span class='varid'>e1</span> <span class='varid'>e2</span><span class='layout'>)</span> <span class='keyglyph'>=</span> <span class='varid'>nullable</span> <span class='varid'>e1</span> <span class='varop'>&&</span>
<a name="line-249"></a> <span class='varid'>not</span> <span class='layout'>(</span><span class='varid'>nullable</span> <span class='varid'>e2</span><span class='layout'>)</span>
<a name="line-250"></a>
<a name="line-251"></a><span class='comment'>-- ------------------------------------------------------------</span>
<a name="line-252"></a>
<a name="line-253"></a><a name="delta"></a><span class='definition'>delta</span> <span class='keyglyph'>::</span> <span class='conid'>Regex</span> <span class='keyglyph'>-></span> <span class='conid'>Char</span> <span class='keyglyph'>-></span> <span class='conid'>Regex</span>
<a name="line-254"></a><span class='definition'>delta</span> <span class='varid'>e</span><span class='keyglyph'>@</span><span class='layout'>(</span><span class='conid'>Zero</span> <span class='keyword'>_</span><span class='layout'>)</span> <span class='keyword'>_</span> <span class='keyglyph'>=</span> <span class='varid'>e</span>
<a name="line-255"></a><span class='definition'>delta</span> <span class='conid'>Unit</span> <span class='varid'>c</span> <span class='keyglyph'>=</span> <span class='varid'>mkZero</span> <span class='varop'>$</span>
<a name="line-256"></a> <span class='str'>"unexpected char "</span> <span class='varop'>++</span> <span class='varid'>show</span> <span class='varid'>c</span>
<a name="line-257"></a><span class='definition'>delta</span> <span class='layout'>(</span><span class='conid'>Sym</span> <span class='varid'>p</span><span class='layout'>)</span> <span class='varid'>c</span>
<a name="line-258"></a> <span class='keyglyph'>|</span> <span class='varid'>p</span> <span class='varid'>c</span> <span class='keyglyph'>=</span> <span class='varid'>mkUnit</span>
<a name="line-259"></a> <span class='keyglyph'>|</span> <span class='varid'>otherwise</span> <span class='keyglyph'>=</span> <span class='varid'>mkZero</span> <span class='varop'>$</span>
<a name="line-260"></a> <span class='str'>"unexpected char "</span> <span class='varop'>++</span> <span class='varid'>show</span> <span class='varid'>c</span> <span class='varop'>++</span> <span class='str'>", expected: "</span> <span class='varop'>++</span> <span class='varid'>oneof</span> <span class='varop'>++</span> <span class='varid'>chars'</span>
<a name="line-261"></a> <span class='keyword'>where</span>
<a name="line-262"></a> <span class='layout'>(</span><span class='varid'>cs</span><span class='layout'>,</span> <span class='varid'>ds</span><span class='layout'>)</span> <span class='keyglyph'>=</span> <span class='varid'>splitAt</span> <span class='num'>40</span> <span class='layout'>(</span><span class='varid'>chars</span> <span class='varid'>p</span><span class='layout'>)</span>
<a name="line-263"></a> <span class='varid'>oneof</span>
<a name="line-264"></a> <span class='keyglyph'>|</span> <span class='varid'>null</span> <span class='layout'>(</span><span class='varid'>tail</span> <span class='varid'>cs</span><span class='layout'>)</span> <span class='keyglyph'>=</span> <span class='str'>""</span>
<a name="line-265"></a> <span class='keyglyph'>|</span> <span class='varid'>otherwise</span> <span class='keyglyph'>=</span> <span class='str'>"one of "</span>
<a name="line-266"></a> <span class='varid'>chars'</span>
<a name="line-267"></a> <span class='keyglyph'>|</span> <span class='varid'>null</span> <span class='layout'>(</span><span class='varid'>tail</span> <span class='varid'>cs</span><span class='layout'>)</span> <span class='keyglyph'>=</span> <span class='str'>"'"</span> <span class='varop'>++</span> <span class='varid'>cs</span> <span class='varop'>++</span> <span class='str'>"'"</span>
<a name="line-268"></a> <span class='keyglyph'>|</span> <span class='varid'>null</span> <span class='varid'>ds</span> <span class='keyglyph'>=</span> <span class='str'>"["</span> <span class='varop'>++</span> <span class='varid'>cs</span> <span class='varop'>++</span> <span class='str'>"]"</span>
<a name="line-269"></a> <span class='keyglyph'>|</span> <span class='varid'>otherwise</span> <span class='keyglyph'>=</span> <span class='str'>"["</span> <span class='varop'>++</span> <span class='varid'>cs</span> <span class='varop'>++</span> <span class='str'>"...]"</span>
<a name="line-270"></a>
<a name="line-271"></a><span class='definition'>delta</span> <span class='conid'>Dot</span> <span class='keyword'>_</span> <span class='keyglyph'>=</span> <span class='varid'>mkUnit</span>
<a name="line-272"></a><span class='definition'>delta</span> <span class='varid'>e</span><span class='keyglyph'>@</span><span class='layout'>(</span><span class='conid'>Star</span> <span class='varid'>e1</span><span class='layout'>)</span> <span class='varid'>c</span> <span class='keyglyph'>=</span> <span class='varid'>mkSeq</span> <span class='layout'>(</span><span class='varid'>delta</span> <span class='varid'>e1</span> <span class='varid'>c</span><span class='layout'>)</span> <span class='varid'>e</span>
<a name="line-273"></a><span class='definition'>delta</span> <span class='layout'>(</span><span class='conid'>Alt</span> <span class='varid'>e1</span> <span class='varid'>e2</span><span class='layout'>)</span> <span class='varid'>c</span> <span class='keyglyph'>=</span> <span class='varid'>mkAlt</span> <span class='layout'>(</span><span class='varid'>delta</span> <span class='varid'>e1</span> <span class='varid'>c</span><span class='layout'>)</span> <span class='layout'>(</span><span class='varid'>delta</span> <span class='varid'>e2</span> <span class='varid'>c</span><span class='layout'>)</span>
<a name="line-274"></a><span class='definition'>delta</span> <span class='layout'>(</span><span class='conid'>Seq</span> <span class='varid'>e1</span> <span class='varid'>e2</span><span class='layout'>)</span> <span class='varid'>c</span>
<a name="line-275"></a> <span class='keyglyph'>|</span> <span class='varid'>nullable</span> <span class='varid'>e1</span> <span class='keyglyph'>=</span> <span class='varid'>mkAlt</span> <span class='layout'>(</span><span class='varid'>mkSeq</span> <span class='layout'>(</span><span class='varid'>delta</span> <span class='varid'>e1</span> <span class='varid'>c</span><span class='layout'>)</span> <span class='varid'>e2</span><span class='layout'>)</span> <span class='layout'>(</span><span class='varid'>delta</span> <span class='varid'>e2</span> <span class='varid'>c</span><span class='layout'>)</span>
<a name="line-276"></a> <span class='keyglyph'>|</span> <span class='varid'>otherwise</span> <span class='keyglyph'>=</span> <span class='varid'>mkSeq</span> <span class='layout'>(</span><span class='varid'>delta</span> <span class='varid'>e1</span> <span class='varid'>c</span><span class='layout'>)</span> <span class='varid'>e2</span>
<a name="line-277"></a><span class='definition'>delta</span> <span class='layout'>(</span><span class='conid'>Rep</span> <span class='varid'>i</span> <span class='varid'>e</span><span class='layout'>)</span> <span class='varid'>c</span> <span class='keyglyph'>=</span> <span class='varid'>mkSeq</span> <span class='layout'>(</span><span class='varid'>delta</span> <span class='varid'>e</span> <span class='varid'>c</span><span class='layout'>)</span> <span class='layout'>(</span><span class='varid'>mkRep</span> <span class='layout'>(</span><span class='varid'>i</span><span class='comment'>-</span><span class='num'>1</span><span class='layout'>)</span> <span class='varid'>e</span><span class='layout'>)</span>
<a name="line-278"></a><span class='definition'>delta</span> <span class='layout'>(</span><span class='conid'>Rng</span> <span class='varid'>i</span> <span class='varid'>j</span> <span class='varid'>e</span><span class='layout'>)</span> <span class='varid'>c</span> <span class='keyglyph'>=</span> <span class='varid'>mkSeq</span> <span class='layout'>(</span><span class='varid'>delta</span> <span class='varid'>e</span> <span class='varid'>c</span><span class='layout'>)</span> <span class='layout'>(</span><span class='varid'>mkRng</span> <span class='layout'>(</span><span class='layout'>(</span><span class='varid'>i</span><span class='comment'>-</span><span class='num'>1</span><span class='layout'>)</span> <span class='varop'>`max`</span> <span class='num'>0</span><span class='layout'>)</span> <span class='layout'>(</span><span class='varid'>j</span><span class='comment'>-</span><span class='num'>1</span><span class='layout'>)</span> <span class='varid'>e</span><span class='layout'>)</span>
<a name="line-279"></a><span class='definition'>delta</span> <span class='layout'>(</span><span class='conid'>Dif</span> <span class='varid'>e1</span> <span class='varid'>e2</span><span class='layout'>)</span> <span class='varid'>c</span> <span class='keyglyph'>=</span> <span class='varid'>mkDif</span> <span class='layout'>(</span><span class='varid'>delta</span> <span class='varid'>e1</span> <span class='varid'>c</span><span class='layout'>)</span> <span class='layout'>(</span><span class='varid'>delta</span> <span class='varid'>e2</span> <span class='varid'>c</span><span class='layout'>)</span>
<a name="line-280"></a>
<a name="line-281"></a><span class='comment'>-- ------------------------------------------------------------</span>
<a name="line-282"></a>
<a name="line-283"></a><a name="delta'"></a><span class='definition'>delta'</span> <span class='keyglyph'>::</span> <span class='conid'>Regex</span> <span class='keyglyph'>-></span> <span class='conid'>String</span> <span class='keyglyph'>-></span> <span class='conid'>Regex</span>
<a name="line-284"></a><span class='definition'>delta'</span> <span class='keyglyph'>=</span> <span class='varid'>foldl</span> <span class='varid'>delta</span>
<a name="line-285"></a>
<a name="line-286"></a><a name="matchWithRE"></a><span class='definition'>matchWithRE</span> <span class='keyglyph'>::</span> <span class='conid'>Regex</span> <span class='keyglyph'>-></span> <span class='conid'>String</span> <span class='keyglyph'>-></span> <span class='conid'>Maybe</span> <span class='conid'>String</span>
<a name="line-287"></a><span class='definition'>matchWithRE</span> <span class='varid'>e</span>
<a name="line-288"></a> <span class='keyglyph'>=</span> <span class='varid'>res</span> <span class='varop'>.</span> <span class='varid'>delta'</span> <span class='varid'>e</span>
<a name="line-289"></a> <span class='keyword'>where</span>
<a name="line-290"></a> <span class='varid'>res</span> <span class='layout'>(</span><span class='conid'>Zero</span> <span class='varid'>err</span><span class='layout'>)</span> <span class='keyglyph'>=</span> <span class='conid'>Just</span> <span class='varid'>err</span>
<a name="line-291"></a> <span class='varid'>res</span> <span class='varid'>re</span>
<a name="line-292"></a> <span class='keyglyph'>|</span> <span class='varid'>nullable</span> <span class='varid'>re</span> <span class='keyglyph'>=</span> <span class='conid'>Nothing</span> <span class='comment'>-- o.k.</span>
<a name="line-293"></a> <span class='keyglyph'>|</span> <span class='varid'>otherwise</span> <span class='keyglyph'>=</span> <span class='conid'>Just</span> <span class='varop'>$</span> <span class='str'>"input does not match "</span> <span class='varop'>++</span> <span class='varid'>show</span> <span class='varid'>e</span>
<a name="line-294"></a>
<a name="line-295"></a><span class='comment'>-- ------------------------------------------------------------</span>
</pre></body>
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