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<pre><a name="line-1"></a><span class='hs-comment'>{-# LANGUAGE UndecidableInstances, OverlappingInstances #-}</span>
<a name="line-2"></a><span class='hs-comment'>{-
<a name="line-3"></a>Copyright (C) 2004-2008 John Goerzen <jgoerzen@complete.org>
<a name="line-4"></a>
<a name="line-5"></a>This program is free software; you can redistribute it and/or modify
<a name="line-6"></a>it under the terms of the GNU Lesser General Public License as published by
<a name="line-7"></a>the Free Software Foundation; either version 2.1 of the License, or
<a name="line-8"></a>(at your option) any later version.
<a name="line-9"></a>
<a name="line-10"></a>This program is distributed in the hope that it will be useful,
<a name="line-11"></a>but WITHOUT ANY WARRANTY; without even the implied warranty of
<a name="line-12"></a>MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
<a name="line-13"></a>GNU Lesser General Public License for more details.
<a name="line-14"></a>
<a name="line-15"></a>You should have received a copy of the GNU Lesser General Public License
<a name="line-16"></a>along with this program; if not, write to the Free Software
<a name="line-17"></a>Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
<a name="line-18"></a>-}</span>
<a name="line-19"></a>
<a name="line-20"></a><span class='hs-comment'>{- |
<a name="line-21"></a> Module : Data.ConfigFile
<a name="line-22"></a> Copyright : Copyright (C) 2004-2008 John Goerzen
<a name="line-23"></a> License : GNU LGPL, version 2.1 or above
<a name="line-24"></a>
<a name="line-25"></a> Maintainer : John Goerzen <jgoerzen@complete.org>
<a name="line-26"></a> Stability : provisional
<a name="line-27"></a> Portability: portable
<a name="line-28"></a>
<a name="line-29"></a>Configuration file parsing, generation, and manipulation
<a name="line-30"></a>
<a name="line-31"></a>Copyright (c) 2004-2008 John Goerzen, jgoerzen\@complete.org
<a name="line-32"></a>
<a name="line-33"></a>This module contains extensive documentation. Please scroll down to the Introduction section to continue reading.
<a name="line-34"></a>-}</span>
<a name="line-35"></a><span class='hs-keyword'>module</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>ConfigFile</span>
<a name="line-36"></a> <span class='hs-layout'>(</span>
<a name="line-37"></a> <span class='hs-comment'>-- * Introduction</span>
<a name="line-38"></a> <span class='hs-comment'>-- $introduction</span>
<a name="line-39"></a>
<a name="line-40"></a> <span class='hs-comment'>-- ** Features</span>
<a name="line-41"></a> <span class='hs-comment'>-- $features</span>
<a name="line-42"></a>
<a name="line-43"></a> <span class='hs-comment'>-- ** History</span>
<a name="line-44"></a> <span class='hs-comment'>-- $history</span>
<a name="line-45"></a>
<a name="line-46"></a> <span class='hs-comment'>-- * Configuration File Format</span>
<a name="line-47"></a> <span class='hs-comment'>-- $format</span>
<a name="line-48"></a>
<a name="line-49"></a> <span class='hs-comment'>-- ** White Space</span>
<a name="line-50"></a> <span class='hs-comment'>-- $whitespace</span>
<a name="line-51"></a>
<a name="line-52"></a> <span class='hs-comment'>-- ** Comments</span>
<a name="line-53"></a> <span class='hs-comment'>-- $comments</span>
<a name="line-54"></a>
<a name="line-55"></a> <span class='hs-comment'>-- ** Case Sensitivity</span>
<a name="line-56"></a> <span class='hs-comment'>-- $casesens</span>
<a name="line-57"></a>
<a name="line-58"></a> <span class='hs-comment'>-- ** Interpolation</span>
<a name="line-59"></a> <span class='hs-comment'>-- $interpolation</span>
<a name="line-60"></a>
<a name="line-61"></a> <span class='hs-comment'>-- * Usage Examples</span>
<a name="line-62"></a> <span class='hs-comment'>-- $usage</span>
<a name="line-63"></a>
<a name="line-64"></a> <span class='hs-comment'>-- ** Non-Monadic Usage</span>
<a name="line-65"></a> <span class='hs-comment'>-- $usagenomonad</span>
<a name="line-66"></a>
<a name="line-67"></a> <span class='hs-comment'>-- ** Error Monad Usage</span>
<a name="line-68"></a> <span class='hs-comment'>-- $usageerrormonad</span>
<a name="line-69"></a>
<a name="line-70"></a> <span class='hs-comment'>-- ** Combined Error\/IO Monad Usage</span>
<a name="line-71"></a> <span class='hs-comment'>-- $usageerroriomonad</span>
<a name="line-72"></a>
<a name="line-73"></a> <span class='hs-comment'>-- * Types</span>
<a name="line-74"></a> <span class='hs-comment'>-- $types</span>
<a name="line-75"></a> <span class='hs-conid'>SectionSpec</span><span class='hs-layout'>,</span> <span class='hs-conid'>OptionSpec</span><span class='hs-layout'>,</span> <span class='hs-conid'>ConfigParser</span><span class='hs-layout'>(</span><span class='hs-keyglyph'>..</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span>
<a name="line-76"></a> <span class='hs-conid'>CPErrorData</span><span class='hs-layout'>(</span><span class='hs-keyglyph'>..</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span> <span class='hs-conid'>CPError</span><span class='hs-layout'>,</span>
<a name="line-77"></a> <span class='hs-comment'>-- * Initialization</span>
<a name="line-78"></a> <span class='hs-comment'>-- $initialization</span>
<a name="line-79"></a> <span class='hs-varid'>emptyCP</span><span class='hs-layout'>,</span>
<a name="line-80"></a>
<a name="line-81"></a> <span class='hs-comment'>-- * Configuring the ConfigParser</span>
<a name="line-82"></a> <span class='hs-comment'>-- $configuringcp</span>
<a name="line-83"></a>
<a name="line-84"></a> <span class='hs-comment'>-- ** Access Functions</span>
<a name="line-85"></a> <span class='hs-varid'>simpleAccess</span><span class='hs-layout'>,</span> <span class='hs-varid'>interpolatingAccess</span><span class='hs-layout'>,</span>
<a name="line-86"></a>
<a name="line-87"></a> <span class='hs-comment'>-- * Reading</span>
<a name="line-88"></a> <span class='hs-comment'>-- $reading</span>
<a name="line-89"></a> <span class='hs-varid'>readfile</span><span class='hs-layout'>,</span> <span class='hs-varid'>readhandle</span><span class='hs-layout'>,</span> <span class='hs-varid'>readstring</span><span class='hs-layout'>,</span>
<a name="line-90"></a>
<a name="line-91"></a> <span class='hs-comment'>-- * Accessing Data</span>
<a name="line-92"></a> <span class='hs-conid'>Get_C</span><span class='hs-layout'>(</span><span class='hs-keyglyph'>..</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span>
<a name="line-93"></a> <span class='hs-varid'>sections</span><span class='hs-layout'>,</span> <span class='hs-varid'>has_section</span><span class='hs-layout'>,</span>
<a name="line-94"></a> <span class='hs-varid'>options</span><span class='hs-layout'>,</span> <span class='hs-varid'>has_option</span><span class='hs-layout'>,</span>
<a name="line-95"></a> <span class='hs-varid'>items</span><span class='hs-layout'>,</span>
<a name="line-96"></a>
<a name="line-97"></a> <span class='hs-comment'>-- * Modifying Data</span>
<a name="line-98"></a> <span class='hs-varid'>set</span><span class='hs-layout'>,</span> <span class='hs-varid'>setshow</span><span class='hs-layout'>,</span> <span class='hs-varid'>remove_option</span><span class='hs-layout'>,</span>
<a name="line-99"></a> <span class='hs-varid'>add_section</span><span class='hs-layout'>,</span> <span class='hs-varid'>remove_section</span><span class='hs-layout'>,</span>
<a name="line-100"></a> <span class='hs-varid'>merge</span><span class='hs-layout'>,</span>
<a name="line-101"></a>
<a name="line-102"></a> <span class='hs-comment'>-- * Output Data</span>
<a name="line-103"></a> <span class='hs-varid'>to_string</span>
<a name="line-104"></a>
<a name="line-105"></a> <span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-106"></a>
<a name="line-107"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>ConfigFile</span><span class='hs-varop'>.</span><span class='hs-conid'>Types</span>
<a name="line-108"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>ConfigFile</span><span class='hs-varop'>.</span><span class='hs-conid'>Parser</span>
<a name="line-109"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Either</span><span class='hs-varop'>.</span><span class='hs-conid'>Utils</span>
<a name="line-110"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>String</span><span class='hs-varop'>.</span><span class='hs-conid'>Utils</span>
<a name="line-111"></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> <span class='hs-keyword'>as</span> <span class='hs-conid'>Map</span>
<a name="line-112"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>List</span>
<a name="line-113"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>System</span><span class='hs-varop'>.</span><span class='hs-conid'>IO</span><span class='hs-layout'>(</span><span class='hs-conid'>Handle</span><span class='hs-layout'>)</span>
<a name="line-114"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Char</span>
<a name="line-115"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Control</span><span class='hs-varop'>.</span><span class='hs-conid'>Monad</span><span class='hs-varop'>.</span><span class='hs-conid'>Error</span>
<a name="line-116"></a>
<a name="line-117"></a><span class='hs-comment'>-- For interpolatingAccess</span>
<a name="line-118"></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'>Parsec</span><span class='hs-varop'>.</span><span class='hs-conid'>Error</span> <span class='hs-layout'>(</span><span class='hs-varid'>errorMessages</span><span class='hs-layout'>,</span> <span class='hs-conid'>Message</span><span class='hs-layout'>(</span><span class='hs-keyglyph'>..</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-119"></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'>Parsec</span> <span class='hs-layout'>(</span><span class='hs-varid'>parse</span><span class='hs-layout'>)</span>
<a name="line-120"></a>
<a name="line-121"></a><span class='hs-comment'>----------------------------------------------------------------------</span>
<a name="line-122"></a><span class='hs-comment'>-- Basic types / default values</span>
<a name="line-123"></a><span class='hs-comment'>----------------------------------------------------------------------</span>
<a name="line-124"></a>
<a name="line-125"></a><a name="emptyCP"></a><span class='hs-comment'>{- | The default empty 'Data.ConfigFile' object.
<a name="line-126"></a>
<a name="line-127"></a>The content contains only an empty mandatory @DEFAULT@ section.
<a name="line-128"></a>
<a name="line-129"></a>'optionxform' is set to @map toLower@.
<a name="line-130"></a>
<a name="line-131"></a>'usedefault' is set to @True@.
<a name="line-132"></a>
<a name="line-133"></a>'accessfunc' is set to 'simpleAccess'.
<a name="line-134"></a>-}</span>
<a name="line-135"></a><span class='hs-definition'>emptyCP</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>ConfigParser</span>
<a name="line-136"></a><span class='hs-definition'>emptyCP</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>ConfigParser</span> <span class='hs-layout'>{</span> <span class='hs-varid'>content</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>fromAL</span> <span class='hs-keyglyph'>[</span><span class='hs-layout'>(</span><span class='hs-str'>"DEFAULT"</span><span class='hs-layout'>,</span> <span class='hs-conid'>[]</span><span class='hs-layout'>)</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>,</span>
<a name="line-137"></a> <span class='hs-varid'>defaulthandler</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>defdefaulthandler</span><span class='hs-layout'>,</span>
<a name="line-138"></a> <span class='hs-varid'>optionxform</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>map</span> <span class='hs-varid'>toLower</span><span class='hs-layout'>,</span>
<a name="line-139"></a> <span class='hs-varid'>usedefault</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>True</span><span class='hs-layout'>,</span>
<a name="line-140"></a> <span class='hs-varid'>accessfunc</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>simpleAccess</span><span class='hs-layout'>}</span>
<a name="line-141"></a>
<a name="line-142"></a><a name="fromAL"></a><span class='hs-comment'>{- | Low-level tool to convert a parsed object into a 'CPData'
<a name="line-143"></a>representation. Performs no option conversions or special handling
<a name="line-144"></a>of @DEFAULT@. -}</span>
<a name="line-145"></a><span class='hs-definition'>fromAL</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>ParseOutput</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>CPData</span>
<a name="line-146"></a><span class='hs-definition'>fromAL</span> <span class='hs-varid'>origal</span> <span class='hs-keyglyph'>=</span>
<a name="line-147"></a> <span class='hs-keyword'>let</span> <span class='hs-varid'>conv</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>CPData</span> <span class='hs-keyglyph'>-></span> <span class='hs-layout'>(</span><span class='hs-conid'>String</span><span class='hs-layout'>,</span> <span class='hs-keyglyph'>[</span><span class='hs-layout'>(</span><span class='hs-conid'>String</span><span class='hs-layout'>,</span> <span class='hs-conid'>String</span><span class='hs-layout'>)</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>CPData</span>
<a name="line-148"></a> <span class='hs-varid'>conv</span> <span class='hs-varid'>fm</span> <span class='hs-varid'>sect</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Map</span><span class='hs-varop'>.</span><span class='hs-varid'>insert</span> <span class='hs-layout'>(</span><span class='hs-varid'>fst</span> <span class='hs-varid'>sect</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</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'>snd</span> <span class='hs-varid'>sect</span><span class='hs-layout'>)</span> <span class='hs-varid'>fm</span>
<a name="line-149"></a> <span class='hs-keyword'>in</span>
<a name="line-150"></a> <span class='hs-varid'>foldl</span> <span class='hs-varid'>conv</span> <span class='hs-conid'>Map</span><span class='hs-varop'>.</span><span class='hs-varid'>empty</span> <span class='hs-varid'>origal</span>
<a name="line-151"></a>
<a name="line-152"></a><a name="simpleAccess"></a><span class='hs-comment'>{- | Default (non-interpolating) access function -}</span>
<a name="line-153"></a><span class='hs-definition'>simpleAccess</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>MonadError</span> <span class='hs-conid'>CPError</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=></span>
<a name="line-154"></a> <span class='hs-conid'>ConfigParser</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>SectionSpec</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>OptionSpec</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-conid'>String</span>
<a name="line-155"></a><span class='hs-definition'>simpleAccess</span> <span class='hs-varid'>cp</span> <span class='hs-varid'>s</span> <span class='hs-varid'>o</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>defdefaulthandler</span> <span class='hs-varid'>cp</span> <span class='hs-varid'>s</span> <span class='hs-layout'>(</span><span class='hs-varid'>optionxform</span> <span class='hs-varid'>cp</span> <span class='hs-varop'>$</span> <span class='hs-varid'>o</span><span class='hs-layout'>)</span>
<a name="line-156"></a>
<a name="line-157"></a><a name="interpolatingAccess"></a><span class='hs-comment'>{- | Interpolating access function. Please see the Interpolation section
<a name="line-158"></a>above for a background on interpolation.
<a name="line-159"></a>
<a name="line-160"></a>Although the format string looks similar to one used by "Text.Printf",
<a name="line-161"></a>it is not the same. In particular, only the %(...)s format is supported.
<a name="line-162"></a>No width specifiers are supported and no conversions other than s are supported.
<a name="line-163"></a>
<a name="line-164"></a>To use this function, you must specify a maximum recursion depth for
<a name="line-165"></a>interpolation. This is used to prevent a stack overflow in the event that
<a name="line-166"></a>the configuration file contains an endless interpolation loop. Values of 10
<a name="line-167"></a>or so are usually more than enough, though you could probably go into the
<a name="line-168"></a>hundreds or thousands before you have actual problems.
<a name="line-169"></a>
<a name="line-170"></a>A value less than one will cause an instant error every time you attempt
<a name="line-171"></a>a lookup.
<a name="line-172"></a>
<a name="line-173"></a>This access method can cause 'get' and friends to return a new 'CPError':
<a name="line-174"></a>'InterpolationError'. This error would be returned when:
<a name="line-175"></a>
<a name="line-176"></a> * The configuration file makes a reference to an option that does
<a name="line-177"></a> not exist
<a name="line-178"></a>
<a name="line-179"></a> * The maximum interpolation depth is exceeded
<a name="line-180"></a>
<a name="line-181"></a> * There is a syntax error processing a %-directive in the configuration
<a name="line-182"></a> file
<a name="line-183"></a>
<a name="line-184"></a>An interpolation lookup name specifies an option only. There is no provision
<a name="line-185"></a>to specify a section. Interpolation variables are looked up in the current
<a name="line-186"></a>section, and, if 'usedefault' is True, in @DEFAULT@ according to the normal
<a name="line-187"></a>logic.
<a name="line-188"></a>
<a name="line-189"></a>To use a literal percent sign, you must place @%%@ in the configuration
<a name="line-190"></a>file when interpolation is used.
<a name="line-191"></a>
<a name="line-192"></a>Here is how you might enable interpolation:
<a name="line-193"></a>
<a name="line-194"></a>>let cp2 = cp {accessfunc = interpolatingAccess 10}
<a name="line-195"></a>
<a name="line-196"></a>The @cp2@ object will now support interpolation with a maximum depth of 10.
<a name="line-197"></a> -}</span>
<a name="line-198"></a><span class='hs-definition'>interpolatingAccess</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>MonadError</span> <span class='hs-conid'>CPError</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=></span>
<a name="line-199"></a> <span class='hs-conid'>Int</span> <span class='hs-keyglyph'>-></span>
<a name="line-200"></a> <span class='hs-conid'>ConfigParser</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>SectionSpec</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>OptionSpec</span>
<a name="line-201"></a> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-conid'>String</span>
<a name="line-202"></a>
<a name="line-203"></a><span class='hs-definition'>interpolatingAccess</span> <span class='hs-varid'>maxdepth</span> <span class='hs-varid'>cp</span> <span class='hs-varid'>s</span> <span class='hs-varid'>o</span> <span class='hs-keyglyph'>=</span>
<a name="line-204"></a> <span class='hs-keyword'>if</span> <span class='hs-varid'>maxdepth</span> <span class='hs-varop'><</span> <span class='hs-num'>1</span>
<a name="line-205"></a> <span class='hs-keyword'>then</span> <span class='hs-varid'>interError</span> <span class='hs-str'>"maximum interpolation depth exceeded"</span>
<a name="line-206"></a> <span class='hs-keyword'>else</span> <span class='hs-keyword'>do</span> <span class='hs-varid'>x</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>simpleAccess</span> <span class='hs-varid'>cp</span> <span class='hs-varid'>s</span> <span class='hs-varid'>o</span>
<a name="line-207"></a> <span class='hs-keyword'>case</span> <span class='hs-varid'>parse</span> <span class='hs-layout'>(</span><span class='hs-varid'>interpmain</span> <span class='hs-varop'>$</span> <span class='hs-varid'>lookupfunc</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>s</span> <span class='hs-varop'>++</span> <span class='hs-str'>"/"</span> <span class='hs-varop'>++</span> <span class='hs-varid'>o</span><span class='hs-layout'>)</span> <span class='hs-varid'>x</span> <span class='hs-keyword'>of</span>
<a name="line-208"></a> <span class='hs-conid'>Left</span> <span class='hs-varid'>y</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyword'>case</span> <span class='hs-varid'>head</span> <span class='hs-layout'>(</span><span class='hs-varid'>errorMessages</span> <span class='hs-varid'>y</span><span class='hs-layout'>)</span> <span class='hs-keyword'>of</span>
<a name="line-209"></a> <span class='hs-conid'>Message</span> <span class='hs-varid'>z</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>interError</span> <span class='hs-varid'>z</span>
<a name="line-210"></a> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>interError</span> <span class='hs-layout'>(</span><span class='hs-varid'>show</span> <span class='hs-varid'>y</span><span class='hs-layout'>)</span>
<a name="line-211"></a> <span class='hs-conid'>Right</span> <span class='hs-varid'>y</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>return</span> <span class='hs-varid'>y</span>
<a name="line-212"></a> <span class='hs-keyword'>where</span>
<a name="line-213"></a> <span class='hs-varid'>lookupfunc</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>interpolatingAccess</span> <span class='hs-layout'>(</span><span class='hs-varid'>maxdepth</span> <span class='hs-comment'>-</span> <span class='hs-num'>1</span><span class='hs-layout'>)</span> <span class='hs-varid'>cp</span> <span class='hs-varid'>s</span>
<a name="line-214"></a> <span class='hs-varid'>interError</span> <span class='hs-varid'>x</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>throwError</span> <span class='hs-layout'>(</span><span class='hs-conid'>InterpolationError</span> <span class='hs-varid'>x</span><span class='hs-layout'>,</span> <span class='hs-str'>"interpolatingAccess"</span><span class='hs-layout'>)</span>
<a name="line-215"></a>
<a name="line-216"></a><a name="defdefaulthandler"></a><span class='hs-comment'>-- internal function: default handler</span>
<a name="line-217"></a><span class='hs-definition'>defdefaulthandler</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>MonadError</span> <span class='hs-conid'>CPError</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=></span>
<a name="line-218"></a> <span class='hs-conid'>ConfigParser</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>SectionSpec</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>OptionSpec</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-conid'>String</span>
<a name="line-219"></a>
<a name="line-220"></a><span class='hs-definition'>defdefaulthandler</span> <span class='hs-varid'>cp</span> <span class='hs-varid'>sectn</span> <span class='hs-varid'>opt</span> <span class='hs-keyglyph'>=</span>
<a name="line-221"></a> <span class='hs-keyword'>let</span> <span class='hs-varid'>fm</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>content</span> <span class='hs-varid'>cp</span>
<a name="line-222"></a> <span class='hs-varid'>lookUp</span> <span class='hs-varid'>s</span> <span class='hs-varid'>o</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-varid'>sect</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>maybeToEither</span> <span class='hs-layout'>(</span><span class='hs-conid'>NoSection</span> <span class='hs-varid'>s</span><span class='hs-layout'>,</span>
<a name="line-223"></a> <span class='hs-str'>"get "</span> <span class='hs-varop'>++</span> <span class='hs-varid'>formatSO</span> <span class='hs-varid'>sectn</span> <span class='hs-varid'>opt</span><span class='hs-layout'>)</span> <span class='hs-varop'>$</span>
<a name="line-224"></a> <span class='hs-conid'>Map</span><span class='hs-varop'>.</span><span class='hs-varid'>lookup</span> <span class='hs-varid'>s</span> <span class='hs-varid'>fm</span>
<a name="line-225"></a> <span class='hs-varid'>maybeToEither</span> <span class='hs-layout'>(</span><span class='hs-conid'>NoOption</span> <span class='hs-varid'>o</span><span class='hs-layout'>,</span>
<a name="line-226"></a> <span class='hs-str'>"get "</span> <span class='hs-varop'>++</span> <span class='hs-varid'>formatSO</span> <span class='hs-varid'>sectn</span> <span class='hs-varid'>opt</span><span class='hs-layout'>)</span> <span class='hs-varop'>$</span>
<a name="line-227"></a> <span class='hs-conid'>Map</span><span class='hs-varop'>.</span><span class='hs-varid'>lookup</span> <span class='hs-varid'>o</span> <span class='hs-varid'>sect</span>
<a name="line-228"></a> <span class='hs-varid'>trydefault</span> <span class='hs-varid'>e</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>if</span> <span class='hs-layout'>(</span><span class='hs-varid'>usedefault</span> <span class='hs-varid'>cp</span><span class='hs-layout'>)</span>
<a name="line-229"></a> <span class='hs-keyword'>then</span>
<a name="line-230"></a> <span class='hs-varid'>lookUp</span> <span class='hs-str'>"DEFAULT"</span> <span class='hs-varid'>opt</span>
<a name="line-231"></a> <span class='hs-comment'>-- Use original error if it's not in DEFAULT either</span>
<a name="line-232"></a> <span class='hs-varop'>`catchError`</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>\</span><span class='hs-keyword'>_</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>throwError</span> <span class='hs-varid'>e</span><span class='hs-layout'>)</span>
<a name="line-233"></a> <span class='hs-keyword'>else</span> <span class='hs-varid'>throwError</span> <span class='hs-varid'>e</span>
<a name="line-234"></a> <span class='hs-keyword'>in</span>
<a name="line-235"></a> <span class='hs-varid'>lookUp</span> <span class='hs-varid'>sectn</span> <span class='hs-varid'>opt</span> <span class='hs-varop'>`catchError`</span> <span class='hs-varid'>trydefault</span>
<a name="line-236"></a>
<a name="line-237"></a>
<a name="line-238"></a><a name="merge"></a><span class='hs-comment'>{- | Combines two 'ConfigParser's into one.
<a name="line-239"></a>
<a name="line-240"></a>Any duplicate options are resolved to contain the value specified in
<a name="line-241"></a>the second parser.
<a name="line-242"></a>
<a name="line-243"></a>The 'ConfigParser' options in the resulting object will be set as they
<a name="line-244"></a>are in the second one passed to this function. -}</span>
<a name="line-245"></a><span class='hs-definition'>merge</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>ConfigParser</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>ConfigParser</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>ConfigParser</span>
<a name="line-246"></a><span class='hs-definition'>merge</span> <span class='hs-varid'>src</span> <span class='hs-varid'>dest</span> <span class='hs-keyglyph'>=</span>
<a name="line-247"></a> <span class='hs-keyword'>let</span> <span class='hs-varid'>conv</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>String</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>String</span>
<a name="line-248"></a> <span class='hs-varid'>conv</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>optionxform</span> <span class='hs-varid'>dest</span>
<a name="line-249"></a> <span class='hs-varid'>convFM</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>CPOptions</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>CPOptions</span>
<a name="line-250"></a> <span class='hs-varid'>convFM</span> <span class='hs-keyglyph'>=</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'>map</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>\</span><span class='hs-varid'>x</span> <span class='hs-keyglyph'>-></span> <span class='hs-layout'>(</span><span class='hs-varid'>conv</span> <span class='hs-layout'>(</span><span class='hs-varid'>fst</span> <span class='hs-varid'>x</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span> <span class='hs-varid'>snd</span> <span class='hs-varid'>x</span><span class='hs-layout'>)</span><span class='hs-layout'>)</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-251"></a> <span class='hs-varid'>mergesects</span> <span class='hs-varid'>a</span> <span class='hs-varid'>b</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Map</span><span class='hs-varop'>.</span><span class='hs-varid'>union</span> <span class='hs-varid'>a</span> <span class='hs-varid'>b</span>
<a name="line-252"></a> <span class='hs-keyword'>in</span>
<a name="line-253"></a> <span class='hs-varid'>dest</span> <span class='hs-layout'>{</span> <span class='hs-varid'>content</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Map</span><span class='hs-varop'>.</span><span class='hs-varid'>unionWith</span> <span class='hs-varid'>mergesects</span>
<a name="line-254"></a> <span class='hs-layout'>(</span><span class='hs-varid'>content</span> <span class='hs-varid'>dest</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-conid'>Map</span><span class='hs-varop'>.</span><span class='hs-varid'>map</span> <span class='hs-varid'>convFM</span> <span class='hs-layout'>(</span><span class='hs-varid'>content</span> <span class='hs-varid'>src</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-layout'>}</span>
<a name="line-255"></a>
<a name="line-256"></a><a name="readutil"></a><span class='hs-comment'>{- | Utility to do a special case merge. -}</span>
<a name="line-257"></a><span class='hs-definition'>readutil</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>ConfigParser</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>ParseOutput</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>ConfigParser</span>
<a name="line-258"></a><span class='hs-definition'>readutil</span> <span class='hs-varid'>old</span> <span class='hs-varid'>new</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>merge</span> <span class='hs-varid'>old</span> <span class='hs-varop'>$</span> <span class='hs-varid'>old</span> <span class='hs-layout'>{</span> <span class='hs-varid'>content</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>fromAL</span> <span class='hs-varid'>new</span> <span class='hs-layout'>}</span>
<a name="line-259"></a>
<a name="line-260"></a><a name="readfile"></a><span class='hs-comment'>{- | Loads data from the specified file. It is then combined with the
<a name="line-261"></a>given 'ConfigParser' using the semantics documented under 'merge' with the
<a name="line-262"></a>new data taking precedence over the old. However, unlike
<a name="line-263"></a>'merge', all the options
<a name="line-264"></a>as set in the old object are preserved since the on-disk representation
<a name="line-265"></a>does not convey those options.
<a name="line-266"></a>
<a name="line-267"></a>May return an error if there is a syntax error. May raise an exception if the file could not be accessed.
<a name="line-268"></a>-}</span>
<a name="line-269"></a><span class='hs-comment'>--readfile :: ConfigParser -> FilePath ->IO (CPResult ConfigParser)</span>
<a name="line-270"></a><span class='hs-definition'>readfile</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>MonadError</span> <span class='hs-conid'>CPError</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>ConfigParser</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>FilePath</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-layout'>(</span><span class='hs-varid'>m</span> <span class='hs-conid'>ConfigParser</span><span class='hs-layout'>)</span>
<a name="line-271"></a><span class='hs-comment'>{-
<a name="line-272"></a>readfile cp fp = do n <- parse_file fp
<a name="line-273"></a> return $ do y <- n
<a name="line-274"></a> return $ readutil cp y
<a name="line-275"></a>-}</span>
<a name="line-276"></a><span class='hs-definition'>readfile</span> <span class='hs-varid'>cp</span> <span class='hs-varid'>fp</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-varid'>n</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>parse_file</span> <span class='hs-varid'>fp</span>
<a name="line-277"></a> <span class='hs-varid'>return</span> <span class='hs-varop'>$</span> <span class='hs-varid'>n</span> <span class='hs-varop'>>>=</span> <span class='hs-layout'>(</span><span class='hs-varid'>return</span> <span class='hs-varop'>.</span> <span class='hs-varid'>readutil</span> <span class='hs-varid'>cp</span><span class='hs-layout'>)</span>
<a name="line-278"></a>
<a name="line-279"></a><a name="readhandle"></a><span class='hs-comment'>{- | Like 'readfile', but uses an already-open handle. You should
<a name="line-280"></a>use 'readfile' instead of this if possible, since it will be able to
<a name="line-281"></a>generate better error messages.
<a name="line-282"></a>
<a name="line-283"></a>Errors would be returned on a syntax error.
<a name="line-284"></a>-}</span>
<a name="line-285"></a><span class='hs-comment'>--readhandle :: ConfigParser -> Handle -> IO (CPResult ConfigParser)</span>
<a name="line-286"></a><span class='hs-definition'>readhandle</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>MonadError</span> <span class='hs-conid'>CPError</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>ConfigParser</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Handle</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-layout'>(</span><span class='hs-varid'>m</span> <span class='hs-conid'>ConfigParser</span><span class='hs-layout'>)</span>
<a name="line-287"></a><span class='hs-definition'>readhandle</span> <span class='hs-varid'>cp</span> <span class='hs-varid'>h</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-varid'>n</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>parse_handle</span> <span class='hs-varid'>h</span>
<a name="line-288"></a> <span class='hs-varid'>return</span> <span class='hs-varop'>$</span> <span class='hs-varid'>n</span> <span class='hs-varop'>>>=</span> <span class='hs-layout'>(</span><span class='hs-varid'>return</span> <span class='hs-varop'>.</span> <span class='hs-layout'>(</span><span class='hs-varid'>readutil</span> <span class='hs-varid'>cp</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-289"></a>
<a name="line-290"></a><a name="readstring"></a><span class='hs-comment'>{- | Like 'readfile', but uses a string. You should use 'readfile'
<a name="line-291"></a>instead of this if you are processing a file, since it can generate
<a name="line-292"></a>better error messages.
<a name="line-293"></a>
<a name="line-294"></a>Errors would be returned on a syntax error.
<a name="line-295"></a>-}</span>
<a name="line-296"></a><span class='hs-definition'>readstring</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>MonadError</span> <span class='hs-conid'>CPError</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=></span>
<a name="line-297"></a> <span class='hs-conid'>ConfigParser</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>String</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-conid'>ConfigParser</span>
<a name="line-298"></a><span class='hs-definition'>readstring</span> <span class='hs-varid'>cp</span> <span class='hs-varid'>s</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span>
<a name="line-299"></a> <span class='hs-varid'>n</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>parse_string</span> <span class='hs-varid'>s</span>
<a name="line-300"></a> <span class='hs-varid'>return</span> <span class='hs-varop'>$</span> <span class='hs-varid'>readutil</span> <span class='hs-varid'>cp</span> <span class='hs-varid'>n</span>
<a name="line-301"></a>
<a name="line-302"></a><a name="sections"></a><span class='hs-comment'>{- | Returns a list of sections in your configuration file. Never includes
<a name="line-303"></a>the always-present section @DEFAULT@. -}</span>
<a name="line-304"></a><span class='hs-definition'>sections</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>ConfigParser</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>SectionSpec</span><span class='hs-keyglyph'>]</span>
<a name="line-305"></a><span class='hs-definition'>sections</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>filter</span> <span class='hs-layout'>(</span><span class='hs-varop'>/=</span> <span class='hs-str'>"DEFAULT"</span><span class='hs-layout'>)</span> <span class='hs-varop'>.</span> <span class='hs-conid'>Map</span><span class='hs-varop'>.</span><span class='hs-varid'>keys</span> <span class='hs-varop'>.</span> <span class='hs-varid'>content</span>
<a name="line-306"></a>
<a name="line-307"></a><a name="has_section"></a><span class='hs-comment'>{- | Indicates whether the given section exists.
<a name="line-308"></a>
<a name="line-309"></a>No special @DEFAULT@ processing is done. -}</span>
<a name="line-310"></a><span class='hs-definition'>has_section</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>ConfigParser</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>SectionSpec</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Bool</span>
<a name="line-311"></a><span class='hs-definition'>has_section</span> <span class='hs-varid'>cp</span> <span class='hs-varid'>x</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Map</span><span class='hs-varop'>.</span><span class='hs-varid'>member</span> <span class='hs-varid'>x</span> <span class='hs-layout'>(</span><span class='hs-varid'>content</span> <span class='hs-varid'>cp</span><span class='hs-layout'>)</span>
<a name="line-312"></a>
<a name="line-313"></a><a name="add_section"></a><span class='hs-comment'>{- | Adds the specified section name. Returns a
<a name="line-314"></a>'SectionAlreadyExists' error if the
<a name="line-315"></a>section was already present. Otherwise, returns the new
<a name="line-316"></a>'ConfigParser' object.-}</span>
<a name="line-317"></a><span class='hs-definition'>add_section</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>MonadError</span> <span class='hs-conid'>CPError</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=></span>
<a name="line-318"></a> <span class='hs-conid'>ConfigParser</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>SectionSpec</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-conid'>ConfigParser</span>
<a name="line-319"></a><span class='hs-definition'>add_section</span> <span class='hs-varid'>cp</span> <span class='hs-varid'>s</span> <span class='hs-keyglyph'>=</span>
<a name="line-320"></a> <span class='hs-keyword'>if</span> <span class='hs-varid'>has_section</span> <span class='hs-varid'>cp</span> <span class='hs-varid'>s</span>
<a name="line-321"></a> <span class='hs-keyword'>then</span> <span class='hs-varid'>throwError</span> <span class='hs-varop'>$</span> <span class='hs-layout'>(</span><span class='hs-conid'>SectionAlreadyExists</span> <span class='hs-varid'>s</span><span class='hs-layout'>,</span> <span class='hs-str'>"add_section"</span><span class='hs-layout'>)</span>
<a name="line-322"></a> <span class='hs-keyword'>else</span> <span class='hs-varid'>return</span> <span class='hs-varop'>$</span> <span class='hs-varid'>cp</span> <span class='hs-layout'>{</span><span class='hs-varid'>content</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Map</span><span class='hs-varop'>.</span><span class='hs-varid'>insert</span> <span class='hs-varid'>s</span> <span class='hs-conid'>Map</span><span class='hs-varop'>.</span><span class='hs-varid'>empty</span> <span class='hs-layout'>(</span><span class='hs-varid'>content</span> <span class='hs-varid'>cp</span><span class='hs-layout'>)</span><span class='hs-layout'>}</span>
<a name="line-323"></a>
<a name="line-324"></a><a name="remove_section"></a><span class='hs-comment'>{- | Removes the specified section. Returns a 'NoSection' error if
<a name="line-325"></a>the section does not exist; otherwise, returns the new 'ConfigParser'
<a name="line-326"></a>object.
<a name="line-327"></a>
<a name="line-328"></a>This call may not be used to remove the @DEFAULT@ section. Attempting to do
<a name="line-329"></a>so will always cause a 'NoSection' error.
<a name="line-330"></a> -}</span>
<a name="line-331"></a><span class='hs-definition'>remove_section</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>MonadError</span> <span class='hs-conid'>CPError</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=></span>
<a name="line-332"></a> <span class='hs-conid'>ConfigParser</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>SectionSpec</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-conid'>ConfigParser</span>
<a name="line-333"></a><span class='hs-definition'>remove_section</span> <span class='hs-keyword'>_</span> <span class='hs-str'>"DEFAULT"</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>throwError</span> <span class='hs-varop'>$</span> <span class='hs-layout'>(</span><span class='hs-conid'>NoSection</span> <span class='hs-str'>"DEFAULT"</span><span class='hs-layout'>,</span> <span class='hs-str'>"remove_section"</span><span class='hs-layout'>)</span>
<a name="line-334"></a><span class='hs-definition'>remove_section</span> <span class='hs-varid'>cp</span> <span class='hs-varid'>s</span> <span class='hs-keyglyph'>=</span>
<a name="line-335"></a> <span class='hs-keyword'>if</span> <span class='hs-varid'>has_section</span> <span class='hs-varid'>cp</span> <span class='hs-varid'>s</span>
<a name="line-336"></a> <span class='hs-keyword'>then</span> <span class='hs-varid'>return</span> <span class='hs-varop'>$</span> <span class='hs-varid'>cp</span> <span class='hs-layout'>{</span><span class='hs-varid'>content</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Map</span><span class='hs-varop'>.</span><span class='hs-varid'>delete</span> <span class='hs-varid'>s</span> <span class='hs-layout'>(</span><span class='hs-varid'>content</span> <span class='hs-varid'>cp</span><span class='hs-layout'>)</span><span class='hs-layout'>}</span>
<a name="line-337"></a> <span class='hs-keyword'>else</span> <span class='hs-varid'>throwError</span> <span class='hs-varop'>$</span> <span class='hs-layout'>(</span><span class='hs-conid'>NoSection</span> <span class='hs-varid'>s</span><span class='hs-layout'>,</span> <span class='hs-str'>"remove_section"</span><span class='hs-layout'>)</span>
<a name="line-338"></a>
<a name="line-339"></a><a name="remove_option"></a><span class='hs-comment'>{- | Removes the specified option. Returns a 'NoSection' error if the
<a name="line-340"></a>section does not exist and a 'NoOption' error if the option does not
<a name="line-341"></a>exist. Otherwise, returns the new 'ConfigParser' object.
<a name="line-342"></a>-}</span>
<a name="line-343"></a><span class='hs-definition'>remove_option</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>MonadError</span> <span class='hs-conid'>CPError</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=></span>
<a name="line-344"></a> <span class='hs-conid'>ConfigParser</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>SectionSpec</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>OptionSpec</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-conid'>ConfigParser</span>
<a name="line-345"></a><span class='hs-definition'>remove_option</span> <span class='hs-varid'>cp</span> <span class='hs-varid'>s</span> <span class='hs-varid'>passedo</span> <span class='hs-keyglyph'>=</span>
<a name="line-346"></a> <span class='hs-keyword'>do</span> <span class='hs-varid'>sectmap</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>maybeToEither</span> <span class='hs-layout'>(</span><span class='hs-conid'>NoSection</span> <span class='hs-varid'>s</span><span class='hs-layout'>,</span>
<a name="line-347"></a> <span class='hs-str'>"remove_option "</span> <span class='hs-varop'>++</span> <span class='hs-varid'>formatSO</span> <span class='hs-varid'>s</span> <span class='hs-varid'>passedo</span><span class='hs-layout'>)</span> <span class='hs-varop'>$</span>
<a name="line-348"></a> <span class='hs-conid'>Map</span><span class='hs-varop'>.</span><span class='hs-varid'>lookup</span> <span class='hs-varid'>s</span> <span class='hs-layout'>(</span><span class='hs-varid'>content</span> <span class='hs-varid'>cp</span><span class='hs-layout'>)</span>
<a name="line-349"></a> <span class='hs-keyword'>let</span> <span class='hs-varid'>o</span> <span class='hs-keyglyph'>=</span> <span class='hs-layout'>(</span><span class='hs-varid'>optionxform</span> <span class='hs-varid'>cp</span><span class='hs-layout'>)</span> <span class='hs-varid'>passedo</span>
<a name="line-350"></a> <span class='hs-keyword'>let</span> <span class='hs-varid'>newsect</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Map</span><span class='hs-varop'>.</span><span class='hs-varid'>delete</span> <span class='hs-varid'>o</span> <span class='hs-varid'>sectmap</span>
<a name="line-351"></a> <span class='hs-keyword'>let</span> <span class='hs-varid'>newmap</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Map</span><span class='hs-varop'>.</span><span class='hs-varid'>insert</span> <span class='hs-varid'>s</span> <span class='hs-varid'>newsect</span> <span class='hs-layout'>(</span><span class='hs-varid'>content</span> <span class='hs-varid'>cp</span><span class='hs-layout'>)</span>
<a name="line-352"></a> <span class='hs-keyword'>if</span> <span class='hs-conid'>Map</span><span class='hs-varop'>.</span><span class='hs-varid'>member</span> <span class='hs-varid'>o</span> <span class='hs-varid'>sectmap</span>
<a name="line-353"></a> <span class='hs-keyword'>then</span> <span class='hs-varid'>return</span> <span class='hs-varop'>$</span> <span class='hs-varid'>cp</span> <span class='hs-layout'>{</span><span class='hs-varid'>content</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>newmap</span><span class='hs-layout'>}</span>
<a name="line-354"></a> <span class='hs-keyword'>else</span> <span class='hs-varid'>throwError</span> <span class='hs-varop'>$</span> <span class='hs-layout'>(</span><span class='hs-conid'>NoOption</span> <span class='hs-varid'>o</span><span class='hs-layout'>,</span>
<a name="line-355"></a> <span class='hs-str'>"remove_option "</span> <span class='hs-varop'>++</span> <span class='hs-varid'>formatSO</span> <span class='hs-varid'>s</span> <span class='hs-varid'>passedo</span><span class='hs-layout'>)</span>
<a name="line-356"></a>
<a name="line-357"></a><a name="options"></a><span class='hs-comment'>{- | Returns a list of the names of all the options present in the
<a name="line-358"></a>given section.
<a name="line-359"></a>
<a name="line-360"></a>Returns an error if the given section does not exist.
<a name="line-361"></a>-}</span>
<a name="line-362"></a><span class='hs-definition'>options</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>MonadError</span> <span class='hs-conid'>CPError</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=></span>
<a name="line-363"></a> <span class='hs-conid'>ConfigParser</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>SectionSpec</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>OptionSpec</span><span class='hs-keyglyph'>]</span>
<a name="line-364"></a><span class='hs-definition'>options</span> <span class='hs-varid'>cp</span> <span class='hs-varid'>x</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>maybeToEither</span> <span class='hs-layout'>(</span><span class='hs-conid'>NoSection</span> <span class='hs-varid'>x</span><span class='hs-layout'>,</span> <span class='hs-str'>"options"</span><span class='hs-layout'>)</span> <span class='hs-varop'>$</span>
<a name="line-365"></a> <span class='hs-keyword'>do</span>
<a name="line-366"></a> <span class='hs-varid'>o</span> <span class='hs-keyglyph'><-</span> <span class='hs-conid'>Map</span><span class='hs-varop'>.</span><span class='hs-varid'>lookup</span> <span class='hs-varid'>x</span> <span class='hs-layout'>(</span><span class='hs-varid'>content</span> <span class='hs-varid'>cp</span><span class='hs-layout'>)</span>
<a name="line-367"></a> <span class='hs-varid'>return</span> <span class='hs-varop'>$</span> <span class='hs-conid'>Map</span><span class='hs-varop'>.</span><span class='hs-varid'>keys</span> <span class='hs-varid'>o</span>
<a name="line-368"></a>
<a name="line-369"></a><a name="has_option"></a><span class='hs-comment'>{- | Indicates whether the given option is present. Returns True
<a name="line-370"></a>only if the given section is present AND the given option is present
<a name="line-371"></a>in that section. No special @DEFAULT@ processing is done. No
<a name="line-372"></a>exception could be raised or error returned.
<a name="line-373"></a>-}</span>
<a name="line-374"></a><span class='hs-definition'>has_option</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>ConfigParser</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>SectionSpec</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>OptionSpec</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Bool</span>
<a name="line-375"></a><span class='hs-definition'>has_option</span> <span class='hs-varid'>cp</span> <span class='hs-varid'>s</span> <span class='hs-varid'>o</span> <span class='hs-keyglyph'>=</span>
<a name="line-376"></a> <span class='hs-keyword'>let</span> <span class='hs-varid'>c</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>content</span> <span class='hs-varid'>cp</span>
<a name="line-377"></a> <span class='hs-varid'>v</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-varid'>secthash</span> <span class='hs-keyglyph'><-</span> <span class='hs-conid'>Map</span><span class='hs-varop'>.</span><span class='hs-varid'>lookup</span> <span class='hs-varid'>s</span> <span class='hs-varid'>c</span>
<a name="line-378"></a> <span class='hs-varid'>return</span> <span class='hs-varop'>$</span> <span class='hs-conid'>Map</span><span class='hs-varop'>.</span><span class='hs-varid'>member</span> <span class='hs-layout'>(</span><span class='hs-varid'>optionxform</span> <span class='hs-varid'>cp</span> <span class='hs-varop'>$</span> <span class='hs-varid'>o</span><span class='hs-layout'>)</span> <span class='hs-varid'>secthash</span>
<a name="line-379"></a> <span class='hs-keyword'>in</span> <span class='hs-varid'>maybe</span> <span class='hs-conid'>False</span> <span class='hs-varid'>id</span> <span class='hs-varid'>v</span>
<a name="line-380"></a>
<a name="line-381"></a><a name="ConfigParser"></a><span class='hs-comment'>{- | The class representing the data types that can be returned by "get".
<a name="line-382"></a>-}</span>
<a name="line-383"></a><a name="ConfigParser"></a><span class='hs-keyword'>class</span> <span class='hs-conid'>Get_C</span> <span class='hs-varid'>a</span> <span class='hs-keyword'>where</span>
<a name="line-384"></a> <span class='hs-comment'>{- | Retrieves a string from the configuration file.
<a name="line-385"></a>
<a name="line-386"></a>When used in a context where a String is expected, returns that string verbatim.
<a name="line-387"></a>
<a name="line-388"></a>When used in a context where a Bool is expected, parses the string to
<a name="line-389"></a>a Boolean value (see logic below).
<a name="line-390"></a>
<a name="line-391"></a>When used in a context where anything that is an instance of Read is expected,
<a name="line-392"></a>calls read to parse the item.
<a name="line-393"></a>
<a name="line-394"></a>An error will be returned of no such option could be found or if it could
<a name="line-395"></a>not be parsed as a boolean (when returning a Bool).
<a name="line-396"></a>
<a name="line-397"></a>When parsing to a Bool, strings are case-insentively converted as follows:
<a name="line-398"></a>
<a name="line-399"></a>The following will produce a True value:
<a name="line-400"></a>
<a name="line-401"></a> * 1
<a name="line-402"></a>
<a name="line-403"></a> * yes
<a name="line-404"></a>
<a name="line-405"></a> * on
<a name="line-406"></a>
<a name="line-407"></a> * enabled
<a name="line-408"></a>
<a name="line-409"></a> * true
<a name="line-410"></a>
<a name="line-411"></a>The following will produce a False value:
<a name="line-412"></a>
<a name="line-413"></a> * 0
<a name="line-414"></a>
<a name="line-415"></a> * no
<a name="line-416"></a>
<a name="line-417"></a> * off
<a name="line-418"></a>
<a name="line-419"></a> * disabled
<a name="line-420"></a>
<a name="line-421"></a> * false -}</span>
<a name="line-422"></a> <span class='hs-varid'>get</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>MonadError</span> <span class='hs-conid'>CPError</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>ConfigParser</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>SectionSpec</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>OptionSpec</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span>
<a name="line-423"></a>
<a name="line-424"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>Get_C</span> <span class='hs-conid'>String</span> <span class='hs-keyword'>where</span>
<a name="line-425"></a> <span class='hs-varid'>get</span> <span class='hs-varid'>cp</span> <span class='hs-varid'>s</span> <span class='hs-varid'>o</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>eitherToMonadError</span> <span class='hs-varop'>$</span> <span class='hs-layout'>(</span><span class='hs-varid'>accessfunc</span> <span class='hs-varid'>cp</span><span class='hs-layout'>)</span> <span class='hs-varid'>cp</span> <span class='hs-varid'>s</span> <span class='hs-varid'>o</span>
<a name="line-426"></a>
<a name="line-427"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>Get_C</span> <span class='hs-conid'>Bool</span> <span class='hs-keyword'>where</span>
<a name="line-428"></a> <span class='hs-varid'>get</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>getbool</span>
<a name="line-429"></a>
<a name="line-430"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>Num</span> <span class='hs-varid'>t</span><span class='hs-layout'>,</span> <span class='hs-conid'>Read</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>Get_C</span> <span class='hs-varid'>t</span> <span class='hs-keyword'>where</span>
<a name="line-431"></a> <span class='hs-varid'>get</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>genericget</span>
<a name="line-432"></a>
<a name="line-433"></a><a name="genericget"></a><span class='hs-definition'>genericget</span> <span class='hs-keyglyph'>::</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'>MonadError</span> <span class='hs-conid'>CPError</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>ConfigParser</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>SectionSpec</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>OptionSpec</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-varid'>b</span>
<a name="line-434"></a><span class='hs-definition'>genericget</span> <span class='hs-varid'>cp</span> <span class='hs-varid'>s</span> <span class='hs-varid'>o</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>get</span> <span class='hs-varid'>cp</span> <span class='hs-varid'>s</span> <span class='hs-varid'>o</span> <span class='hs-varop'>>>=</span> <span class='hs-varid'>return</span> <span class='hs-varop'>.</span> <span class='hs-varid'>read</span>
<a name="line-435"></a>
<a name="line-436"></a><a name="getbool"></a><span class='hs-definition'>getbool</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>MonadError</span> <span class='hs-conid'>CPError</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=></span>
<a name="line-437"></a> <span class='hs-conid'>ConfigParser</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>SectionSpec</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>OptionSpec</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-conid'>Bool</span>
<a name="line-438"></a><span class='hs-definition'>getbool</span> <span class='hs-varid'>cp</span> <span class='hs-varid'>s</span> <span class='hs-varid'>o</span> <span class='hs-keyglyph'>=</span>
<a name="line-439"></a> <span class='hs-keyword'>do</span> <span class='hs-varid'>val</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>get</span> <span class='hs-varid'>cp</span> <span class='hs-varid'>s</span> <span class='hs-varid'>o</span>
<a name="line-440"></a> <span class='hs-keyword'>case</span> <span class='hs-varid'>map</span> <span class='hs-varid'>toLower</span> <span class='hs-varop'>.</span> <span class='hs-varid'>strip</span> <span class='hs-varop'>$</span> <span class='hs-varid'>val</span> <span class='hs-keyword'>of</span>
<a name="line-441"></a> <span class='hs-str'>"1"</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>return</span> <span class='hs-conid'>True</span>
<a name="line-442"></a> <span class='hs-str'>"yes"</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>return</span> <span class='hs-conid'>True</span>
<a name="line-443"></a> <span class='hs-str'>"on"</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>return</span> <span class='hs-conid'>True</span>
<a name="line-444"></a> <span class='hs-str'>"enabled"</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>return</span> <span class='hs-conid'>True</span>
<a name="line-445"></a> <span class='hs-str'>"true"</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>return</span> <span class='hs-conid'>True</span>
<a name="line-446"></a> <span class='hs-str'>"0"</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>return</span> <span class='hs-conid'>False</span>
<a name="line-447"></a> <span class='hs-str'>"no"</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>return</span> <span class='hs-conid'>False</span>
<a name="line-448"></a> <span class='hs-str'>"off"</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>return</span> <span class='hs-conid'>False</span>
<a name="line-449"></a> <span class='hs-str'>"disabled"</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>return</span> <span class='hs-conid'>False</span>
<a name="line-450"></a> <span class='hs-str'>"false"</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>return</span> <span class='hs-conid'>False</span>
<a name="line-451"></a> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>throwError</span> <span class='hs-layout'>(</span><span class='hs-conid'>ParseError</span> <span class='hs-varop'>$</span> <span class='hs-str'>"couldn't parse bool "</span> <span class='hs-varop'>++</span>
<a name="line-452"></a> <span class='hs-varid'>val</span> <span class='hs-varop'>++</span> <span class='hs-str'>" from "</span> <span class='hs-varop'>++</span> <span class='hs-varid'>formatSO</span> <span class='hs-varid'>s</span> <span class='hs-varid'>o</span><span class='hs-layout'>,</span> <span class='hs-str'>"getbool"</span><span class='hs-layout'>)</span>
<a name="line-453"></a>
<a name="line-454"></a><a name="formatSO"></a><span class='hs-definition'>formatSO</span> <span class='hs-keyglyph'>::</span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Char</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Char</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>Char</span><span class='hs-keyglyph'>]</span>
<a name="line-455"></a><span class='hs-definition'>formatSO</span> <span class='hs-varid'>s</span> <span class='hs-varid'>o</span> <span class='hs-keyglyph'>=</span>
<a name="line-456"></a> <span class='hs-str'>"("</span> <span class='hs-varop'>++</span> <span class='hs-varid'>s</span> <span class='hs-varop'>++</span> <span class='hs-str'>"/"</span> <span class='hs-varop'>++</span> <span class='hs-varid'>o</span> <span class='hs-varop'>++</span> <span class='hs-str'>")"</span>
<a name="line-457"></a>
<a name="line-458"></a>
<a name="line-459"></a><a name="items"></a><span class='hs-comment'>{- | Returns a list of @(optionname, value)@ pairs representing the content
<a name="line-460"></a>of the given section. Returns an error the section is invalid. -}</span>
<a name="line-461"></a><span class='hs-definition'>items</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>MonadError</span> <span class='hs-conid'>CPError</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=></span>
<a name="line-462"></a> <span class='hs-conid'>ConfigParser</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>SectionSpec</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>[</span><span class='hs-layout'>(</span><span class='hs-conid'>OptionSpec</span><span class='hs-layout'>,</span> <span class='hs-conid'>String</span><span class='hs-layout'>)</span><span class='hs-keyglyph'>]</span>
<a name="line-463"></a><span class='hs-definition'>items</span> <span class='hs-varid'>cp</span> <span class='hs-varid'>s</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-varid'>fm</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>maybeToEither</span> <span class='hs-layout'>(</span><span class='hs-conid'>NoSection</span> <span class='hs-varid'>s</span><span class='hs-layout'>,</span> <span class='hs-str'>"items"</span><span class='hs-layout'>)</span> <span class='hs-varop'>$</span>
<a name="line-464"></a> <span class='hs-conid'>Map</span><span class='hs-varop'>.</span><span class='hs-varid'>lookup</span> <span class='hs-varid'>s</span> <span class='hs-layout'>(</span><span class='hs-varid'>content</span> <span class='hs-varid'>cp</span><span class='hs-layout'>)</span>
<a name="line-465"></a> <span class='hs-varid'>return</span> <span class='hs-varop'>$</span> <span class='hs-conid'>Map</span><span class='hs-varop'>.</span><span class='hs-varid'>toList</span> <span class='hs-varid'>fm</span>
<a name="line-466"></a>
<a name="line-467"></a><a name="set"></a><span class='hs-comment'>{- | Sets the option to a new value, replacing an existing one if it exists.
<a name="line-468"></a>
<a name="line-469"></a>Returns an error if the section does not exist. -}</span>
<a name="line-470"></a><span class='hs-definition'>set</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>MonadError</span> <span class='hs-conid'>CPError</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=></span>
<a name="line-471"></a> <span class='hs-conid'>ConfigParser</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>SectionSpec</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>OptionSpec</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>String</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-conid'>ConfigParser</span>
<a name="line-472"></a><span class='hs-definition'>set</span> <span class='hs-varid'>cp</span> <span class='hs-varid'>s</span> <span class='hs-varid'>passedo</span> <span class='hs-varid'>val</span> <span class='hs-keyglyph'>=</span>
<a name="line-473"></a> <span class='hs-keyword'>do</span> <span class='hs-varid'>sectmap</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>maybeToEither</span> <span class='hs-layout'>(</span><span class='hs-conid'>NoSection</span> <span class='hs-varid'>s</span><span class='hs-layout'>,</span> <span class='hs-str'>"set "</span> <span class='hs-varop'>++</span> <span class='hs-varid'>formatSO</span> <span class='hs-varid'>s</span> <span class='hs-varid'>passedo</span><span class='hs-layout'>)</span> <span class='hs-varop'>$</span>
<a name="line-474"></a> <span class='hs-conid'>Map</span><span class='hs-varop'>.</span><span class='hs-varid'>lookup</span> <span class='hs-varid'>s</span> <span class='hs-layout'>(</span><span class='hs-varid'>content</span> <span class='hs-varid'>cp</span><span class='hs-layout'>)</span>
<a name="line-475"></a> <span class='hs-keyword'>let</span> <span class='hs-varid'>o</span> <span class='hs-keyglyph'>=</span> <span class='hs-layout'>(</span><span class='hs-varid'>optionxform</span> <span class='hs-varid'>cp</span><span class='hs-layout'>)</span> <span class='hs-varid'>passedo</span>
<a name="line-476"></a> <span class='hs-keyword'>let</span> <span class='hs-varid'>newsect</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Map</span><span class='hs-varop'>.</span><span class='hs-varid'>insert</span> <span class='hs-varid'>o</span> <span class='hs-varid'>val</span> <span class='hs-varid'>sectmap</span>
<a name="line-477"></a> <span class='hs-keyword'>let</span> <span class='hs-varid'>newmap</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Map</span><span class='hs-varop'>.</span><span class='hs-varid'>insert</span> <span class='hs-varid'>s</span> <span class='hs-varid'>newsect</span> <span class='hs-layout'>(</span><span class='hs-varid'>content</span> <span class='hs-varid'>cp</span><span class='hs-layout'>)</span>
<a name="line-478"></a> <span class='hs-varid'>return</span> <span class='hs-varop'>$</span> <span class='hs-varid'>cp</span> <span class='hs-layout'>{</span> <span class='hs-varid'>content</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>newmap</span><span class='hs-layout'>}</span>
<a name="line-479"></a>
<a name="line-480"></a><a name="setshow"></a><span class='hs-comment'>{- | Sets the option to a new value, replacing an existing one if it exists.
<a name="line-481"></a>It requires only a showable value as its parameter.
<a name="line-482"></a>This can be used with bool values, as well as numeric ones.
<a name="line-483"></a>
<a name="line-484"></a>Returns an error if the section does not exist. -}</span>
<a name="line-485"></a><span class='hs-definition'>setshow</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'>MonadError</span> <span class='hs-conid'>CPError</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=></span>
<a name="line-486"></a> <span class='hs-conid'>ConfigParser</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>SectionSpec</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>OptionSpec</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-conid'>ConfigParser</span>
<a name="line-487"></a><span class='hs-definition'>setshow</span> <span class='hs-varid'>cp</span> <span class='hs-varid'>s</span> <span class='hs-varid'>o</span> <span class='hs-varid'>val</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>set</span> <span class='hs-varid'>cp</span> <span class='hs-varid'>s</span> <span class='hs-varid'>o</span> <span class='hs-layout'>(</span><span class='hs-varid'>show</span> <span class='hs-varid'>val</span><span class='hs-layout'>)</span>
<a name="line-488"></a>
<a name="line-489"></a><a name="to_string"></a><span class='hs-comment'>{- | Converts the 'ConfigParser' to a string representation that could be
<a name="line-490"></a>later re-parsed by this module or modified by a human.
<a name="line-491"></a>
<a name="line-492"></a>Note that this does not necessarily re-create a file that was originally
<a name="line-493"></a>loaded. Things may occur in a different order, comments will be removed,
<a name="line-494"></a>etc. The conversion makes an effort to make the result human-editable,
<a name="line-495"></a>but it does not make an effort to make the result identical to the original
<a name="line-496"></a>input.
<a name="line-497"></a>
<a name="line-498"></a>The result is, however, guaranteed to parse the same as the original input.
<a name="line-499"></a> -}</span>
<a name="line-500"></a><span class='hs-definition'>to_string</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>ConfigParser</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>String</span>
<a name="line-501"></a><span class='hs-definition'>to_string</span> <span class='hs-varid'>cp</span> <span class='hs-keyglyph'>=</span>
<a name="line-502"></a> <span class='hs-keyword'>let</span> <span class='hs-varid'>gen_option</span> <span class='hs-layout'>(</span><span class='hs-varid'>key</span><span class='hs-layout'>,</span> <span class='hs-varid'>value</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span>
<a name="line-503"></a> <span class='hs-varid'>key</span> <span class='hs-varop'>++</span> <span class='hs-str'>": "</span> <span class='hs-varop'>++</span> <span class='hs-layout'>(</span><span class='hs-varid'>replace</span> <span class='hs-str'>"\n"</span> <span class='hs-str'>"\n "</span> <span class='hs-varid'>value</span><span class='hs-layout'>)</span> <span class='hs-varop'>++</span> <span class='hs-str'>"\n"</span>
<a name="line-504"></a> <span class='hs-varid'>gen_section</span> <span class='hs-layout'>(</span><span class='hs-varid'>sect</span><span class='hs-layout'>,</span> <span class='hs-varid'>valfm</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-comment'>-- gen a section, but omit DEFAULT if empty</span>
<a name="line-505"></a> <span class='hs-keyword'>if</span> <span class='hs-layout'>(</span><span class='hs-varid'>sect</span> <span class='hs-varop'>/=</span> <span class='hs-str'>"DEFAULT"</span><span class='hs-layout'>)</span> <span class='hs-varop'>||</span> <span class='hs-layout'>(</span><span class='hs-conid'>Map</span><span class='hs-varop'>.</span><span class='hs-varid'>size</span> <span class='hs-varid'>valfm</span> <span class='hs-varop'>></span> <span class='hs-num'>0</span><span class='hs-layout'>)</span>
<a name="line-506"></a> <span class='hs-keyword'>then</span> <span class='hs-str'>"["</span> <span class='hs-varop'>++</span> <span class='hs-varid'>sect</span> <span class='hs-varop'>++</span> <span class='hs-str'>"]\n"</span> <span class='hs-varop'>++</span>
<a name="line-507"></a> <span class='hs-layout'>(</span><span class='hs-varid'>concat</span> <span class='hs-varop'>$</span> <span class='hs-varid'>map</span> <span class='hs-varid'>gen_option</span> <span class='hs-layout'>(</span><span class='hs-conid'>Map</span><span class='hs-varop'>.</span><span class='hs-varid'>toList</span> <span class='hs-varid'>valfm</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-varop'>++</span> <span class='hs-str'>"\n"</span>
<a name="line-508"></a> <span class='hs-keyword'>else</span> <span class='hs-str'>""</span>
<a name="line-509"></a> <span class='hs-keyword'>in</span>
<a name="line-510"></a> <span class='hs-varid'>concat</span> <span class='hs-varop'>$</span> <span class='hs-varid'>map</span> <span class='hs-varid'>gen_section</span> <span class='hs-layout'>(</span><span class='hs-conid'>Map</span><span class='hs-varop'>.</span><span class='hs-varid'>toList</span> <span class='hs-layout'>(</span><span class='hs-varid'>content</span> <span class='hs-varid'>cp</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-511"></a>
<a name="line-512"></a><span class='hs-comment'>----------------------------------------------------------------------</span>
<a name="line-513"></a><span class='hs-comment'>-- Docs</span>
<a name="line-514"></a><span class='hs-comment'>----------------------------------------------------------------------</span>
<a name="line-515"></a>
<a name="line-516"></a><span class='hs-comment'>{- $introduction
<a name="line-517"></a>
<a name="line-518"></a>Many programs need configuration files. These configuration files are
<a name="line-519"></a>typically used to configure certain runtime behaviors that need to be
<a name="line-520"></a>saved across sessions. Various different configuration file formats
<a name="line-521"></a>exist.
<a name="line-522"></a>
<a name="line-523"></a>The ConfigParser module attempts to define a standard format that is
<a name="line-524"></a>easy for the user to edit, easy for the programmer to work with, yet
<a name="line-525"></a>remains powerful and flexible.
<a name="line-526"></a>-}</span>
<a name="line-527"></a>
<a name="line-528"></a><span class='hs-comment'>{- $features
<a name="line-529"></a>
<a name="line-530"></a>For the programmer, this module provides:
<a name="line-531"></a>
<a name="line-532"></a> * Simple calls to both read /and write/ configuration files
<a name="line-533"></a>
<a name="line-534"></a> * Call that can generate a string version of a file that is
<a name="line-535"></a> re-parsable by this module (useful for, for instance, sending the
<a name="line-536"></a> file down a network)
<a name="line-537"></a>
<a name="line-538"></a> * Segmented configuration files that let you separate configuration
<a name="line-539"></a> into distinct sections, each with its own namespace. This can be
<a name="line-540"></a> used to configure multiple modules in one file, to configure
<a name="line-541"></a> multiple instances of a single object, etc.
<a name="line-542"></a>
<a name="line-543"></a> * On-the-fly parsing of integer, boolean, float, multi-line string values,
<a name="line-544"></a> and anything else Haskell's read can deal with
<a name="line-545"></a>
<a name="line-546"></a> * It is possible to make a configuration file parsable by this
<a name="line-547"></a> module, the Unix shell, and\/or Unix make, though some feautres are,
<a name="line-548"></a> of course, not compatible with these other tools.
<a name="line-549"></a>
<a name="line-550"></a> * Syntax checking with error reporting including line numbers
<a name="line-551"></a>
<a name="line-552"></a> * Implemented in pure Haskell. No dependencies on modules outside
<a name="line-553"></a> the standard library distributed with Haskell compilers or interpreters.
<a name="line-554"></a> All calls except those that read directly from a handle are pure calls
<a name="line-555"></a> and can be used outside the IO monad.
<a name="line-556"></a>
<a name="line-557"></a> * Comprehensive documentation
<a name="line-558"></a>
<a name="line-559"></a> * Extensible API
<a name="line-560"></a>
<a name="line-561"></a> * Complete compatibility with Python's ConfigParser module, or my
<a name="line-562"></a> ConfigParser module for OCaml, part of my MissingLib package.
<a name="line-563"></a>
<a name="line-564"></a>For the user, this module provides:
<a name="line-565"></a>
<a name="line-566"></a> * Easily human-editable configuration files with a clear, concise,
<a name="line-567"></a> and consistent format
<a name="line-568"></a>
<a name="line-569"></a> * Configuration file format consistent with other familiar formats
<a name="line-570"></a> (\/etc\/passwd is a valid ConfigParser file)
<a name="line-571"></a>
<a name="line-572"></a> * No need to understand semantics of markup languages like XML
<a name="line-573"></a>-}</span>
<a name="line-574"></a>
<a name="line-575"></a><span class='hs-comment'>{- $history
<a name="line-576"></a>
<a name="line-577"></a>This module is based on Python's ConfigParser module at
<a name="line-578"></a><<a href="http://www.python.org/doc/current/lib/module-ConfigParser.html">http://www.python.org/doc/current/lib/module-ConfigParser.html</a>>. I had
<a name="line-579"></a>earlier developed an OCaml implementation as part of my MissingLib library
<a name="line-580"></a>at <gopher://gopher.quux.org/devel/missinglib>.
<a name="line-581"></a>
<a name="line-582"></a>While the API of these three modules is similar, and the aim is to preserve all
<a name="line-583"></a>useful features of the original Python module, there are some differences
<a name="line-584"></a>in the implementation details. This module is a complete, clean re-implementation
<a name="line-585"></a>in Haskell, not a Haskell translation of a Python program. As such, the feature
<a name="line-586"></a>set is slightly different.
<a name="line-587"></a>-}</span>
<a name="line-588"></a>
<a name="line-589"></a><span class='hs-comment'>{- $format
<a name="line-590"></a>
<a name="line-591"></a>The basic configuration file format resembles that of an old-style
<a name="line-592"></a>Windows .INI file. Here are two samples:
<a name="line-593"></a>
<a name="line-594"></a>>debug = yes
<a name="line-595"></a>>inputfile = /etc/passwd
<a name="line-596"></a>>names = Peter, Paul, Mary, George, Abrahaham, John, Bill, Gerald, Richard,
<a name="line-597"></a>> Franklin, Woodrow
<a name="line-598"></a>>color = red
<a name="line-599"></a>
<a name="line-600"></a>This defines a file without any explicit section, so all items will
<a name="line-601"></a>occur within the default section @DEFAULT@. The @debug@ option can be read
<a name="line-602"></a>as a boolean or a string. The remaining items can be read as a string
<a name="line-603"></a>only. The @names@ entry spans two lines -- any line starting with
<a name="line-604"></a>whitespace, and containing something other than whitespace or
<a name="line-605"></a>comments, is taken as a continuation of the previous line.
<a name="line-606"></a>
<a name="line-607"></a>Here's another example:
<a name="line-608"></a>
<a name="line-609"></a>># Default options
<a name="line-610"></a>>[DEFAULT]
<a name="line-611"></a>>hostname: localhost
<a name="line-612"></a>># Options for the first file
<a name="line-613"></a>>[file1]
<a name="line-614"></a>>location: /usr/local
<a name="line-615"></a>>user: Fred
<a name="line-616"></a>>uid: 1000
<a name="line-617"></a>>optionaltext: Hello, this entire string is included
<a name="line-618"></a>>[file2]
<a name="line-619"></a>>location: /opt
<a name="line-620"></a>>user: Fred
<a name="line-621"></a>>uid: 1001
<a name="line-622"></a>
<a name="line-623"></a>This file defines three sections. The @DEFAULT@ section specifies an
<a name="line-624"></a>entry @hostname@. If you attempt to read the hostname option in any
<a name="line-625"></a>section, and that section doesn't define @hostname@, you will get the
<a name="line-626"></a>value from @DEFAULT@ instead. This is a nice time-saver. You can also
<a name="line-627"></a>note that you can use colons instead of the = character to separate
<a name="line-628"></a>option names from option entries.
<a name="line-629"></a>-}</span>
<a name="line-630"></a>
<a name="line-631"></a><span class='hs-comment'>{- $whitespace
<a name="line-632"></a>
<a name="line-633"></a>Whitespace (spaces, tabs, etc) is automatically stripped from the
<a name="line-634"></a>beginning and end of all strings. Thus, users can insert whitespace
<a name="line-635"></a>before\/after the colon or equal sign if they like, and it will be
<a name="line-636"></a>automatically stripped.
<a name="line-637"></a>
<a name="line-638"></a>Blank lines or lines consisting solely of whitespace are ignored.
<a name="line-639"></a>
<a name="line-640"></a>A line giving an option or a section name may not begin with white space.
<a name="line-641"></a>This requirement is necessary so there is no ambiguity between such lines
<a name="line-642"></a>and continuation lines for multi-line options.
<a name="line-643"></a>
<a name="line-644"></a>-}</span>
<a name="line-645"></a>
<a name="line-646"></a><span class='hs-comment'>{- $comments
<a name="line-647"></a>
<a name="line-648"></a>Comments are introduced with the pound sign @#@ or the semicolon @;@. They
<a name="line-649"></a>cause the parser to ignore everything from that character to the end
<a name="line-650"></a>of the line.
<a name="line-651"></a>
<a name="line-652"></a>Comments /may not/ occur within the definitions of options; that is, you
<a name="line-653"></a>may not place a comment in the middle of a line such as @user: Fred@.
<a name="line-654"></a>That is because the parser considers the comment characters part
<a name="line-655"></a>of the string; otherwise, you'd be unable to use those characters in
<a name="line-656"></a>your strings. You can, however, \"comment out\" options by putting the
<a name="line-657"></a>comment character at the start of the line.
<a name="line-658"></a>
<a name="line-659"></a>-}</span>
<a name="line-660"></a>
<a name="line-661"></a><span class='hs-comment'>{- $casesens
<a name="line-662"></a>
<a name="line-663"></a>By default, section names are case-sensitive but option names are
<a name="line-664"></a>not. The latter can be adjusted by adjusting 'optionxform'. -}</span>
<a name="line-665"></a>
<a name="line-666"></a><span class='hs-comment'>{- $interpolation
<a name="line-667"></a>
<a name="line-668"></a>Interpolation is an optional feature, disabled by default. If you replace
<a name="line-669"></a>the default 'accessfunc' ('simpleAccess') with 'interpolatingAccess',
<a name="line-670"></a>then you get interpolation support with 'get' and the other 'get'-based functions.
<a name="line-671"></a>
<a name="line-672"></a>As an example, consider the following file:
<a name="line-673"></a>
<a name="line-674"></a>>arch = i386
<a name="line-675"></a>>project = test
<a name="line-676"></a>>filename = test_%(arch)s.c
<a name="line-677"></a>>dir = /usr/src/%(filename)s
<a name="line-678"></a>>percent = 5%%
<a name="line-679"></a>
<a name="line-680"></a>With interpolation, you would get these results:
<a name="line-681"></a>
<a name="line-682"></a>>get cp "DEFAULT" "filename" -> "test_i386.c"
<a name="line-683"></a>>get cp "DEFAULT" "dir" -> "/usr/src/test_i386.c"
<a name="line-684"></a>>get cp "DEFAULT" "percent" -> "5%"
<a name="line-685"></a>
<a name="line-686"></a>For more details on interpolation, please see the documentation for the
<a name="line-687"></a>'interpolatingAccess' function.
<a name="line-688"></a>-}</span>
<a name="line-689"></a>
<a name="line-690"></a><span class='hs-comment'>{- $usage
<a name="line-691"></a>
<a name="line-692"></a>The basic theory of working with ConfigParser is this:
<a name="line-693"></a>
<a name="line-694"></a> 1. Parse or build a 'ConfigParser' object
<a name="line-695"></a>
<a name="line-696"></a> 2. Work with it in one of several ways
<a name="line-697"></a>
<a name="line-698"></a> 3. To make changes, you discard the original object and use a new one.
<a name="line-699"></a> Changes can be "chained" through one of several monads.
<a name="line-700"></a>
<a name="line-701"></a>The default 'ConfigParser' object that you always start with is 'emptyCP'.
<a name="line-702"></a>From here, you load data into it (merging data into the empty object),
<a name="line-703"></a>set up structures yourself, or adjust options.
<a name="line-704"></a>
<a name="line-705"></a>Let's take a look at some basic use cases.
<a name="line-706"></a>
<a name="line-707"></a>-}</span>
<a name="line-708"></a>
<a name="line-709"></a><span class='hs-comment'>{- $usagenomonad
<a name="line-710"></a>You'll notice that many functions in this module return a
<a name="line-711"></a>@MonadError 'CPError'@ over some
<a name="line-712"></a>type. Although its definition is not this simple, you can consider this to be
<a name="line-713"></a>the same as returning @Either CPError a@.
<a name="line-714"></a>
<a name="line-715"></a>That is, these functions will return @Left error@ if there's a problem
<a name="line-716"></a>or @Right result@ if things are fine. The documentation for individual
<a name="line-717"></a>functions describes the specific circumstances in which an error may occur in
<a name="line-718"></a>more detail.
<a name="line-719"></a>
<a name="line-720"></a>Some people find it annoying to have to deal with errors manually.
<a name="line-721"></a>You can transform errors into exceptions in your code by using
<a name="line-722"></a>'Data.Either.Utils.forceEither'. Here's an example of this style of programming:
<a name="line-723"></a>
<a name="line-724"></a>> import Data.Either.Utils
<a name="line-725"></a>> do
<a name="line-726"></a>> val <- readfile emptyCP "/etc/foo.cfg"
<a name="line-727"></a>> let cp = forceEither val
<a name="line-728"></a>> putStrLn "Your setting is:"
<a name="line-729"></a>> putStrLn $ forceEither $ get cp "sect1" "opt1"
<a name="line-730"></a>
<a name="line-731"></a>In short, you can just put @forceEither $@ in front of every call that returns
<a name="line-732"></a>something that is a MonadError.
<a name="line-733"></a>This is still a pure functional call, so it can be used outside
<a name="line-734"></a>of the IO monads. The exception, however, can only be caught in the IO
<a name="line-735"></a>monad.
<a name="line-736"></a>
<a name="line-737"></a>If you don't want to bother with 'forceEither', you can use the error monad. It's simple and better... read on.
<a name="line-738"></a>-}</span>
<a name="line-739"></a>
<a name="line-740"></a><span class='hs-comment'>{- $usageerrormonad
<a name="line-741"></a>
<a name="line-742"></a>The return type is actually defined in terms of the Error monad, which is
<a name="line-743"></a>itself based on the Either data type.
<a name="line-744"></a>
<a name="line-745"></a>Here's a neat example of chaining together calls to build up a 'ConfigParser'
<a name="line-746"></a>object:
<a name="line-747"></a>
<a name="line-748"></a>>do let cp = emptyCP
<a name="line-749"></a>> cp <- add_section cp "sect1"
<a name="line-750"></a>> cp <- set cp "sect1" "opt1" "foo"
<a name="line-751"></a>> cp <- set cp "sect1" "opt2" "bar"
<a name="line-752"></a>> options cp "sect1"
<a name="line-753"></a>
<a name="line-754"></a>The return value of this little snippet is @Right [\"opt1\", \"opt2\"]@.
<a name="line-755"></a>(Note to beginners: unlike the IO monad, you /can/ escape from the Error
<a name="line-756"></a>monad.)
<a name="line-757"></a>
<a name="line-758"></a>Although it's not obvious, there actually was error checking there. If
<a name="line-759"></a>any of those calls would have generated an error, processing would have
<a name="line-760"></a>stopped immediately and a @Left@ value would have been returned. Consider
<a name="line-761"></a>this example:
<a name="line-762"></a>
<a name="line-763"></a>>do let cp = emptyCP
<a name="line-764"></a>> cp <- add_section cp "sect1"
<a name="line-765"></a>> cp <- set cp "sect1" "opt1" "foo"
<a name="line-766"></a>> cp <- set cp "sect2" "opt2" "bar"
<a name="line-767"></a>> options cp "sect1"
<a name="line-768"></a>
<a name="line-769"></a>The return value from this is @Left ('NoSection' \"sect2\", \"set\")@. The
<a name="line-770"></a>second call to 'set' failed, so the final call was skipped, and the result
<a name="line-771"></a>of the entire computation was considered to be an error.
<a name="line-772"></a>
<a name="line-773"></a>You can combine this with the non-monadic style to get a final, pure value
<a name="line-774"></a>out of it:
<a name="line-775"></a>
<a name="line-776"></a>>forceEither $ do let cp = emptyCP
<a name="line-777"></a>> cp <- add_section cp "sect1"
<a name="line-778"></a>> cp <- set cp "sect1" "opt1" "foo"
<a name="line-779"></a>> cp <- set cp "sect1" "opt2" "bar"
<a name="line-780"></a>> options cp "sect1"
<a name="line-781"></a>
<a name="line-782"></a>This returns @[\"opt1\", \"opt2\"]@. A quite normal value.
<a name="line-783"></a>
<a name="line-784"></a>-}</span>
<a name="line-785"></a>
<a name="line-786"></a><span class='hs-comment'>{- $usageerroriomonad
<a name="line-787"></a>
<a name="line-788"></a>You've seen a nice way to use this module in the Error monad and get an Either
<a name="line-789"></a>value out. But that's the Error monad, so IO is not permitted.
<a name="line-790"></a>Using Haskell's monad transformers, you can run it in the combined
<a name="line-791"></a>Error\/IO monad. That is, you will get an IO result back. Here is a full
<a name="line-792"></a>standalone example of doing that:
<a name="line-793"></a>
<a name="line-794"></a>>import Data.ConfigFile
<a name="line-795"></a>>import Control.Monad.Error
<a name="line-796"></a>>
<a name="line-797"></a>>main = do
<a name="line-798"></a>> rv <- runErrorT $
<a name="line-799"></a>> do
<a name="line-800"></a>> cp <- join $ liftIO $ readfile empty "/etc/passwd"
<a name="line-801"></a>> let x = cp
<a name="line-802"></a>> liftIO $ putStrLn "In the test"
<a name="line-803"></a>> nb <- get x "DEFAULT" "nobody"
<a name="line-804"></a>> liftIO $ putStrLn nb
<a name="line-805"></a>> foo <- get x "DEFAULT" "foo"
<a name="line-806"></a>> liftIO $ putStrLn foo
<a name="line-807"></a>> return "done"
<a name="line-808"></a>> print rv
<a name="line-809"></a>
<a name="line-810"></a>On my system, this prints:
<a name="line-811"></a>
<a name="line-812"></a>>In the test
<a name="line-813"></a>>x:65534:65534:nobody:/nonexistent:/bin/sh
<a name="line-814"></a>>Left (NoOption "foo","get")
<a name="line-815"></a>
<a name="line-816"></a>That is, my @\/etc\/passwd@ file contains a @nobody@ user but not a @foo@ user.
<a name="line-817"></a>
<a name="line-818"></a>Let's look at how that works.
<a name="line-819"></a>
<a name="line-820"></a>First, @main@ always runs in the IO monad only, so we take the result from
<a name="line-821"></a>the later calls and put it in @rv@. Note that the combined block
<a name="line-822"></a>is started with @runErrorT $ do@ instead of just @do@.
<a name="line-823"></a>
<a name="line-824"></a>To get something out of the call to 'readfile', we use
<a name="line-825"></a>@join $ liftIO $ readfile@. This will bring the result out of the IO monad
<a name="line-826"></a>into the combined monad and process it like usual. From here on,
<a name="line-827"></a>everything looks normal, except for IO calls. They are all executed under
<a name="line-828"></a>@liftIO@ so that the result value is properly brought into the combined
<a name="line-829"></a>monad. This finally returns @\"done\"@. Since we are in the Error monad, that means that the literal value is @Right \"done\"@. Since we are also in the IO
<a name="line-830"></a>monad, this is wrapped in IO. So the final return type after applying
<a name="line-831"></a>@runErrorT@ is @IO (Either CPError String)@.
<a name="line-832"></a>
<a name="line-833"></a>In this case, there was an error, and processing stopped at that point just
<a name="line-834"></a>like the example of the pure Error monad. We print out the return value,
<a name="line-835"></a>so you see the error displayed as a @Left@ value.
<a name="line-836"></a>
<a name="line-837"></a>It all works quite easily.
<a name="line-838"></a>
<a name="line-839"></a>-}</span>
<a name="line-840"></a>
<a name="line-841"></a><span class='hs-comment'>{- $configuringcp
<a name="line-842"></a>
<a name="line-843"></a>You may notice that the 'ConfigParser' object has some configurable parameters,
<a name="line-844"></a>such as 'usedefault'. In case you're not familiar with the Haskell syntax
<a name="line-845"></a>for working with these, you can use syntax like this to set these options:
<a name="line-846"></a>
<a name="line-847"></a>>let cp2 = cp { usedefault = False }
<a name="line-848"></a>
<a name="line-849"></a>This will create a new 'ConfigParser' that is the same as @cp@ except for
<a name="line-850"></a>the 'usedefault' field, which is now always False. The new object will be
<a name="line-851"></a>called @cp2@ in this example.
<a name="line-852"></a>-}</span>
<a name="line-853"></a>
<a name="line-854"></a><span class='hs-comment'>{- $reading
<a name="line-855"></a>
<a name="line-856"></a>You can use these functions to read data from a file.
<a name="line-857"></a>
<a name="line-858"></a>A common idiom for loading a new object from stratch is:
<a name="line-859"></a>
<a name="line-860"></a>@cp <- 'readfile' 'emptyCP' \"\/etc\/foo.cfg\"@
<a name="line-861"></a>
<a name="line-862"></a>Note the use of 'emptyCP'; this will essentially cause the file's data
<a name="line-863"></a>to be merged with the empty 'ConfigParser'.
<a name="line-864"></a>-}</span>
<a name="line-865"></a>
<a name="line-866"></a><span class='hs-comment'>{- $types
<a name="line-867"></a>
<a name="line-868"></a>The code used to say this:
<a name="line-869"></a>
<a name="line-870"></a>>type CPResult a = MonadError CPError m => m a
<a name="line-871"></a>>simpleAccess :: ConfigParser -> SectionSpec -> OptionSpec -> CPResult String
<a name="line-872"></a>
<a name="line-873"></a>But Hugs did not support that type declaration. Therefore, types are now
<a name="line-874"></a>given like this:
<a name="line-875"></a>
<a name="line-876"></a>>simpleAccess :: MonadError CPError m =>
<a name="line-877"></a>> ConfigParser -> SectionSpec -> OptionSpec -> m String
<a name="line-878"></a>
<a name="line-879"></a>Although it looks more confusing than before, it still means the same.
<a name="line-880"></a>The return value can still be treated as @Either CPError String@ if you so
<a name="line-881"></a>desire.
<a name="line-882"></a>-}</span>
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