hxt-8.0.0: doc/hdoc/src/Data-AssocList.html
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<pre><a name="line-1"></a><span class='comment'>-- |</span>
<a name="line-2"></a><span class='comment'>-- simple key value assocciation list</span>
<a name="line-3"></a><span class='comment'>-- implemented as unordered list of pairs</span>
<a name="line-4"></a><span class='comment'>--</span>
<a name="line-5"></a><span class='comment'>-- Version : $Id: AssocList.hs,v 1.2 2005/05/27 13:15:23 hxml Exp $</span>
<a name="line-6"></a>
<a name="line-7"></a><span class='keyword'>module</span> <span class='conid'>Data</span><span class='varop'>.</span><span class='conid'>AssocList</span>
<a name="line-8"></a> <span class='layout'>(</span> <span class='keyword'>module</span> <span class='conid'>Data</span><span class='varop'>.</span><span class='conid'>AssocList</span>
<a name="line-9"></a> <span class='layout'>)</span>
<a name="line-10"></a><span class='keyword'>where</span>
<a name="line-11"></a>
<a name="line-12"></a><span class='keyword'>import</span> <span class='conid'>Data</span><span class='varop'>.</span><span class='conid'>Maybe</span>
<a name="line-13"></a>
<a name="line-14"></a><a name="AssocList"></a><span class='keyword'>type</span> <span class='conid'>AssocList</span> <span class='varid'>k</span> <span class='varid'>v</span> <span class='keyglyph'>=</span> <span class='keyglyph'>[</span><span class='layout'>(</span><span class='varid'>k</span><span class='layout'>,</span> <span class='varid'>v</span><span class='layout'>)</span><span class='keyglyph'>]</span>
<a name="line-15"></a>
<a name="line-16"></a><span class='comment'>-- lookup = lookup from Prelude</span>
<a name="line-17"></a>
<a name="line-18"></a><span class='comment'>-- | lookup with default value</span>
<a name="line-19"></a>
<a name="line-20"></a><a name="lookupDef"></a><span class='definition'>lookupDef</span> <span class='keyglyph'>::</span> <span class='conid'>Eq</span> <span class='varid'>k</span> <span class='keyglyph'>=></span> <span class='varid'>v</span> <span class='keyglyph'>-></span> <span class='varid'>k</span> <span class='keyglyph'>-></span> <span class='conid'>AssocList</span> <span class='varid'>k</span> <span class='varid'>v</span> <span class='keyglyph'>-></span> <span class='varid'>v</span>
<a name="line-21"></a><span class='definition'>lookupDef</span> <span class='varid'>d</span> <span class='varid'>k</span> <span class='keyglyph'>=</span> <span class='varid'>fromMaybe</span> <span class='varid'>d</span> <span class='varop'>.</span> <span class='varid'>lookup</span> <span class='varid'>k</span>
<a name="line-22"></a>
<a name="line-23"></a><span class='comment'>-- | lookup with empty list (empty string) as default value</span>
<a name="line-24"></a>
<a name="line-25"></a><a name="lookup1"></a><span class='definition'>lookup1</span> <span class='keyglyph'>::</span> <span class='conid'>Eq</span> <span class='varid'>k</span> <span class='keyglyph'>=></span> <span class='varid'>k</span> <span class='keyglyph'>-></span> <span class='conid'>AssocList</span> <span class='varid'>k</span> <span class='keyglyph'>[</span><span class='varid'>e</span><span class='keyglyph'>]</span> <span class='keyglyph'>-></span> <span class='keyglyph'>[</span><span class='varid'>e</span><span class='keyglyph'>]</span>
<a name="line-26"></a><span class='definition'>lookup1</span> <span class='varid'>k</span> <span class='keyglyph'>=</span> <span class='varid'>fromMaybe</span> <span class='conid'>[]</span> <span class='varop'>.</span> <span class='varid'>lookup</span> <span class='varid'>k</span>
<a name="line-27"></a>
<a name="line-28"></a><span class='comment'>-- | test for existence of a key</span>
<a name="line-29"></a>
<a name="line-30"></a><a name="hasEntry"></a><span class='definition'>hasEntry</span> <span class='keyglyph'>::</span> <span class='conid'>Eq</span> <span class='varid'>k</span> <span class='keyglyph'>=></span> <span class='varid'>k</span> <span class='keyglyph'>-></span> <span class='conid'>AssocList</span> <span class='varid'>k</span> <span class='varid'>v</span> <span class='keyglyph'>-></span> <span class='conid'>Bool</span>
<a name="line-31"></a><span class='definition'>hasEntry</span> <span class='varid'>k</span> <span class='keyglyph'>=</span> <span class='varid'>isJust</span> <span class='varop'>.</span> <span class='varid'>lookup</span> <span class='varid'>k</span>
<a name="line-32"></a>
<a name="line-33"></a><span class='comment'>-- | add an entry, remove an existing entry before adding the new one at the top of the list, addEntry is strict</span>
<a name="line-34"></a>
<a name="line-35"></a><a name="addEntry"></a><span class='definition'>addEntry</span> <span class='keyglyph'>::</span> <span class='conid'>Eq</span> <span class='varid'>k</span> <span class='keyglyph'>=></span> <span class='varid'>k</span> <span class='keyglyph'>-></span> <span class='varid'>v</span> <span class='keyglyph'>-></span> <span class='conid'>AssocList</span> <span class='varid'>k</span> <span class='varid'>v</span> <span class='keyglyph'>-></span> <span class='conid'>AssocList</span> <span class='varid'>k</span> <span class='varid'>v</span>
<a name="line-36"></a><span class='definition'>addEntry</span> <span class='varid'>k</span> <span class='varid'>v</span> <span class='varid'>l</span> <span class='keyglyph'>=</span> <span class='layout'>(</span> <span class='layout'>(</span><span class='varid'>k</span><span class='layout'>,</span><span class='varid'>v</span><span class='layout'>)</span> <span class='conop'>:</span> <span class='layout'>)</span> <span class='varop'>$!</span> <span class='varid'>delEntry</span> <span class='varid'>k</span> <span class='varid'>l</span>
<a name="line-37"></a>
<a name="line-38"></a> <span class='comment'>-- let l' = delEntry k l in seq l' ((k, v) : l')</span>
<a name="line-39"></a>
<a name="line-40"></a><span class='comment'>-- | add a whole list of entries with 'addEntry'</span>
<a name="line-41"></a>
<a name="line-42"></a><a name="addEntries"></a><span class='definition'>addEntries</span> <span class='keyglyph'>::</span> <span class='conid'>Eq</span> <span class='varid'>k</span> <span class='keyglyph'>=></span> <span class='conid'>AssocList</span> <span class='varid'>k</span> <span class='varid'>v</span> <span class='keyglyph'>-></span> <span class='conid'>AssocList</span> <span class='varid'>k</span> <span class='varid'>v</span> <span class='keyglyph'>-></span> <span class='conid'>AssocList</span> <span class='varid'>k</span> <span class='varid'>v</span>
<a name="line-43"></a><span class='definition'>addEntries</span> <span class='keyglyph'>=</span> <span class='varid'>foldr</span> <span class='layout'>(</span><span class='varop'>.</span><span class='layout'>)</span> <span class='varid'>id</span> <span class='varop'>.</span> <span class='varid'>map</span> <span class='layout'>(</span><span class='varid'>uncurry</span> <span class='varid'>addEntry</span><span class='layout'>)</span> <span class='varop'>.</span> <span class='varid'>reverse</span>
<a name="line-44"></a>
<a name="line-45"></a><a name="delEntry"></a><span class='comment'>-- | delete an entry, delEntry is strict</span>
<a name="line-46"></a><span class='definition'>delEntry</span> <span class='keyglyph'>::</span> <span class='conid'>Eq</span> <span class='varid'>k</span> <span class='keyglyph'>=></span> <span class='varid'>k</span> <span class='keyglyph'>-></span> <span class='conid'>AssocList</span> <span class='varid'>k</span> <span class='varid'>v</span> <span class='keyglyph'>-></span> <span class='conid'>AssocList</span> <span class='varid'>k</span> <span class='varid'>v</span>
<a name="line-47"></a><span class='definition'>delEntry</span> <span class='keyword'>_</span> <span class='conid'>[]</span> <span class='keyglyph'>=</span> <span class='conid'>[]</span>
<a name="line-48"></a><span class='definition'>delEntry</span> <span class='varid'>k</span> <span class='layout'>(</span><span class='varid'>x</span><span class='keyglyph'>@</span><span class='layout'>(</span><span class='varid'>k1</span><span class='layout'>,</span><span class='keyword'>_</span><span class='layout'>)</span> <span class='conop'>:</span> <span class='varid'>rest</span><span class='layout'>)</span>
<a name="line-49"></a> <span class='keyglyph'>|</span> <span class='varid'>k</span> <span class='varop'>==</span> <span class='varid'>k1</span> <span class='keyglyph'>=</span> <span class='varid'>rest</span>
<a name="line-50"></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='conop'>:</span> <span class='layout'>)</span> <span class='varop'>$!</span> <span class='varid'>delEntry</span> <span class='varid'>k</span> <span class='varid'>rest</span>
<a name="line-51"></a>
<a name="line-52"></a><span class='comment'>-- delEntry k = filter ((/= k) . fst)</span>
<a name="line-53"></a>
<a name="line-54"></a><span class='comment'>-- | delete a list of entries with 'delEntry'</span>
<a name="line-55"></a>
<a name="line-56"></a><a name="delEntries"></a><span class='definition'>delEntries</span> <span class='keyglyph'>::</span> <span class='conid'>Eq</span> <span class='varid'>k</span> <span class='keyglyph'>=></span> <span class='keyglyph'>[</span><span class='varid'>k</span><span class='keyglyph'>]</span> <span class='keyglyph'>-></span> <span class='conid'>AssocList</span> <span class='varid'>k</span> <span class='varid'>v</span> <span class='keyglyph'>-></span> <span class='conid'>AssocList</span> <span class='varid'>k</span> <span class='varid'>v</span>
<a name="line-57"></a><span class='definition'>delEntries</span> <span class='keyglyph'>=</span> <span class='varid'>foldl</span> <span class='layout'>(</span><span class='varop'>.</span><span class='layout'>)</span> <span class='varid'>id</span> <span class='varop'>.</span> <span class='varid'>map</span> <span class='varid'>delEntry</span>
<a name="line-58"></a>
<a name="line-59"></a><span class='comment'>-- -----------------------------------------------------------------------------</span>
<a name="line-60"></a>
<a name="line-61"></a>
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