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<pre><a name="line-1"></a><span class='hs-comment'>{- Copyright (C) 2004-2005 John Goerzen <jgoerzen@complete.org>
<a name="line-2"></a>
<a name="line-3"></a>This program is free software; you can redistribute it and/or modify
<a name="line-4"></a>it under the terms of the GNU General Public License as published by
<a name="line-5"></a>the Free Software Foundation; either version 2 of the License, or
<a name="line-6"></a>(at your option) any later version.
<a name="line-7"></a>
<a name="line-8"></a>This program is distributed in the hope that it will be useful,
<a name="line-9"></a>but WITHOUT ANY WARRANTY; without even the implied warranty of
<a name="line-10"></a>MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
<a name="line-11"></a>GNU General Public License for more details.
<a name="line-12"></a>
<a name="line-13"></a>You should have received a copy of the GNU General Public License
<a name="line-14"></a>along with this program; if not, write to the Free Software
<a name="line-15"></a>Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
<a name="line-16"></a>-}</span>
<a name="line-17"></a>
<a name="line-18"></a><span class='hs-comment'>{- |
<a name="line-19"></a> Module : Data.Map.Utils
<a name="line-20"></a> Copyright : Copyright (C) 2004-2005 John Goerzen
<a name="line-21"></a> License : GNU GPL, version 2 or above
<a name="line-22"></a>
<a name="line-23"></a> Maintainer : John Goerzen <jgoerzen@complete.org>
<a name="line-24"></a> Stability : provisional
<a name="line-25"></a> Portability: portable
<a name="line-26"></a>
<a name="line-27"></a>This module provides various helpful utilities for dealing with Data.Maps.
<a name="line-28"></a>
<a name="line-29"></a>Written by John Goerzen, jgoerzen\@complete.org
<a name="line-30"></a>-}</span>
<a name="line-31"></a>
<a name="line-32"></a><span class='hs-keyword'>module</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Map</span><span class='hs-varop'>.</span><span class='hs-conid'>Utils</span> <span class='hs-layout'>(</span><span class='hs-comment'>-- * Basic Utilities</span>
<a name="line-33"></a> <span class='hs-varid'>flipM</span><span class='hs-layout'>,</span> <span class='hs-varid'>flippedLookupM</span><span class='hs-layout'>,</span> <span class='hs-varid'>forceLookupM</span><span class='hs-layout'>,</span>
<a name="line-34"></a> <span class='hs-comment'>-- * Conversions</span>
<a name="line-35"></a> <span class='hs-varid'>strToM</span><span class='hs-layout'>,</span>
<a name="line-36"></a> <span class='hs-varid'>strFromM</span>
<a name="line-37"></a> <span class='hs-layout'>)</span>
<a name="line-38"></a><span class='hs-keyword'>where</span>
<a name="line-39"></a>
<a name="line-40"></a><span class='hs-keyword'>import</span> <span class='hs-keyword'>qualified</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Map</span>
<a name="line-41"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>List</span><span class='hs-varop'>.</span><span class='hs-conid'>Utils</span><span class='hs-layout'>(</span><span class='hs-varid'>flipAL</span><span class='hs-layout'>,</span> <span class='hs-varid'>strToAL</span><span class='hs-layout'>,</span> <span class='hs-varid'>strFromAL</span><span class='hs-layout'>)</span>
<a name="line-42"></a>
<a name="line-43"></a><a name="strFromM"></a><span class='hs-comment'>{- | Converts a String, String Map into a string representation.
<a name="line-44"></a>See 'Data.List.Utils.strFromAL' for more on the similar function for
<a name="line-45"></a>association lists. This implementation is simple:
<a name="line-46"></a>
<a name="line-47"></a>>strFromM = strFromAL . Data.Map.toList
<a name="line-48"></a>
<a name="line-49"></a>This function is designed to work with Map String String objects,
<a name="line-50"></a>but may also work with other objects with simple representations. -}</span>
<a name="line-51"></a><span class='hs-definition'>strFromM</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>Show</span> <span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-conid'>Show</span> <span class='hs-varid'>b</span><span class='hs-layout'>,</span> <span class='hs-conid'>Ord</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Map</span><span class='hs-varop'>.</span><span class='hs-conid'>Map</span> <span class='hs-varid'>a</span> <span class='hs-varid'>b</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>String</span>
<a name="line-52"></a><span class='hs-definition'>strFromM</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>strFromAL</span> <span class='hs-varop'>.</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Map</span><span class='hs-varop'>.</span><span class='hs-varid'>toList</span>
<a name="line-53"></a>
<a name="line-54"></a><a name="strToM"></a><span class='hs-comment'>{- | Converts a String into a String, String Map. See
<a name="line-55"></a>'Data.List.Utils.strToAL' for more on the similar function for association
<a name="line-56"></a>lists.
<a name="line-57"></a>
<a name="line-58"></a>This implementation is simple:
<a name="line-59"></a>
<a name="line-60"></a>>strToM = Data.Map.fromList . strToAL
<a name="line-61"></a>
<a name="line-62"></a>This function is designed to work with Map String String objects,
<a name="line-63"></a>but may work with other key\/value combinations if they have simple
<a name="line-64"></a>representations. -}</span>
<a name="line-65"></a><span class='hs-definition'>strToM</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>Read</span> <span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-conid'>Read</span> <span class='hs-varid'>b</span><span class='hs-layout'>,</span> <span class='hs-conid'>Ord</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>String</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Map</span><span class='hs-varop'>.</span><span class='hs-conid'>Map</span> <span class='hs-varid'>a</span> <span class='hs-varid'>b</span>
<a name="line-66"></a><span class='hs-definition'>strToM</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Map</span><span class='hs-varop'>.</span><span class='hs-varid'>fromList</span> <span class='hs-varop'>.</span> <span class='hs-varid'>strToAL</span>
<a name="line-67"></a>
<a name="line-68"></a><span class='hs-comment'>{- | Flips a Map. See 'Data.List.Utils.flipAL' for more on the similar
<a name="line-69"></a>function for lists. -}</span>
<a name="line-70"></a>
<a name="line-71"></a><a name="flipM"></a><span class='hs-definition'>flipM</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>Ord</span> <span class='hs-varid'>key</span><span class='hs-layout'>,</span> <span class='hs-conid'>Ord</span> <span class='hs-varid'>val</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Map</span><span class='hs-varop'>.</span><span class='hs-conid'>Map</span> <span class='hs-varid'>key</span> <span class='hs-varid'>val</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Map</span><span class='hs-varop'>.</span><span class='hs-conid'>Map</span> <span class='hs-varid'>val</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>key</span><span class='hs-keyglyph'>]</span>
<a name="line-72"></a><span class='hs-definition'>flipM</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Map</span><span class='hs-varop'>.</span><span class='hs-varid'>fromList</span> <span class='hs-varop'>.</span> <span class='hs-varid'>flipAL</span> <span class='hs-varop'>.</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Map</span><span class='hs-varop'>.</span><span class='hs-varid'>toList</span>
<a name="line-73"></a>
<a name="line-74"></a><span class='hs-comment'>{- | Returns a list of all keys in the Map whose value matches the
<a name="line-75"></a>parameter. If the value does not occur in the Map, the empty
<a name="line-76"></a>list is returned. -}</span>
<a name="line-77"></a>
<a name="line-78"></a><a name="flippedLookupM"></a><span class='hs-definition'>flippedLookupM</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>Ord</span> <span class='hs-varid'>val</span><span class='hs-layout'>,</span> <span class='hs-conid'>Ord</span> <span class='hs-varid'>key</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=></span> <span class='hs-varid'>val</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Map</span><span class='hs-varop'>.</span><span class='hs-conid'>Map</span> <span class='hs-varid'>key</span> <span class='hs-varid'>val</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>key</span><span class='hs-keyglyph'>]</span>
<a name="line-79"></a><span class='hs-definition'>flippedLookupM</span> <span class='hs-varid'>v</span> <span class='hs-varid'>fm</span> <span class='hs-keyglyph'>=</span>
<a name="line-80"></a> <span class='hs-keyword'>case</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Map</span><span class='hs-varop'>.</span><span class='hs-varid'>lookup</span> <span class='hs-varid'>v</span> <span class='hs-layout'>(</span><span class='hs-varid'>flipM</span> <span class='hs-varid'>fm</span><span class='hs-layout'>)</span> <span class='hs-keyword'>of</span>
<a name="line-81"></a> <span class='hs-conid'>Nothing</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>[]</span>
<a name="line-82"></a> <span class='hs-conid'>Just</span> <span class='hs-varid'>x</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>x</span>
<a name="line-83"></a>
<a name="line-84"></a><a name="forceLookupM"></a><span class='hs-comment'>{- | Performs a lookup, and raises an exception (with an error message
<a name="line-85"></a>prepended with the given string) if the key could not be found.
<a name="line-86"></a>-}</span>
<a name="line-87"></a><span class='hs-definition'>forceLookupM</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>Show</span> <span class='hs-varid'>key</span><span class='hs-layout'>,</span> <span class='hs-conid'>Ord</span> <span class='hs-varid'>key</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>String</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>key</span> <span class='hs-keyglyph'>-></span>
<a name="line-88"></a> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Map</span><span class='hs-varop'>.</span><span class='hs-conid'>Map</span> <span class='hs-varid'>key</span> <span class='hs-varid'>elt</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>elt</span>
<a name="line-89"></a><span class='hs-definition'>forceLookupM</span> <span class='hs-varid'>msg</span> <span class='hs-varid'>k</span> <span class='hs-varid'>fm</span> <span class='hs-keyglyph'>=</span>
<a name="line-90"></a> <span class='hs-keyword'>case</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Map</span><span class='hs-varop'>.</span><span class='hs-varid'>lookup</span> <span class='hs-varid'>k</span> <span class='hs-varid'>fm</span> <span class='hs-keyword'>of</span>
<a name="line-91"></a> <span class='hs-conid'>Just</span> <span class='hs-varid'>x</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>x</span>
<a name="line-92"></a> <span class='hs-conid'>Nothing</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>error</span> <span class='hs-varop'>$</span> <span class='hs-varid'>msg</span> <span class='hs-varop'>++</span> <span class='hs-str'>": could not find key "</span> <span class='hs-varop'>++</span> <span class='hs-layout'>(</span><span class='hs-varid'>show</span> <span class='hs-varid'>k</span><span class='hs-layout'>)</span>
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