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<pre><a name="line-1"></a><span class='hs-comment'>{-
<a name="line-2"></a>Copyright (C) 2006-2010 John MacFarlane <jgm@berkeley.edu>
<a name="line-3"></a>
<a name="line-4"></a>This program is free software; you can redistribute it and/or modify
<a name="line-5"></a>it under the terms of the GNU General Public License as published by
<a name="line-6"></a>the Free Software Foundation; either version 2 of the License, or
<a name="line-7"></a>(at your option) any later version.
<a name="line-8"></a>
<a name="line-9"></a>This program is distributed in the hope that it will be useful,
<a name="line-10"></a>but WITHOUT ANY WARRANTY; without even the implied warranty of
<a name="line-11"></a>MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
<a name="line-12"></a>GNU General Public License for more details.
<a name="line-13"></a>
<a name="line-14"></a>You should have received a copy of the GNU General Public License
<a name="line-15"></a>along with this program; if not, write to the Free Software
<a name="line-16"></a>Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
<a name="line-17"></a>-}</span>
<a name="line-18"></a>
<a name="line-19"></a><span class='hs-comment'>{- |
<a name="line-20"></a> Module : Text.Pandoc.Generic
<a name="line-21"></a> Copyright : Copyright (C) 2006-2010 John MacFarlane
<a name="line-22"></a> License : GNU GPL, version 2 or above
<a name="line-23"></a>
<a name="line-24"></a> Maintainer : John MacFarlane <jgm@berkeley.edu>
<a name="line-25"></a> Stability : alpha
<a name="line-26"></a> Portability : portable
<a name="line-27"></a>
<a name="line-28"></a>Generic functions for manipulating 'Pandoc' documents.
<a name="line-29"></a>
<a name="line-30"></a>Here's a simple example, defining a function that replaces all the level 3+
<a name="line-31"></a>headers in a document with regular paragraphs in ALL CAPS:
<a name="line-32"></a>
<a name="line-33"></a>> import Text.Pandoc.Definition
<a name="line-34"></a>> import Text.Pandoc.Generic
<a name="line-35"></a>> import Data.Char (toUpper)
<a name="line-36"></a>>
<a name="line-37"></a>> modHeader :: Block -> Block
<a name="line-38"></a>> modHeader (Header n xs) | n >= 3 = Para $ bottomUp allCaps xs
<a name="line-39"></a>> modHeader x = x
<a name="line-40"></a>>
<a name="line-41"></a>> allCaps :: Inline -> Inline
<a name="line-42"></a>> allCaps (Str xs) = Str $ map toUpper xs
<a name="line-43"></a>> allCaps x = x
<a name="line-44"></a>>
<a name="line-45"></a>> changeHeaders :: Pandoc -> Pandoc
<a name="line-46"></a>> changeHeaders = bottomUp modHeader
<a name="line-47"></a>
<a name="line-48"></a>'bottomUp' is so called because it traverses the @Pandoc@ structure from
<a name="line-49"></a>bottom up. 'topDown' goes the other way. The difference between them can be
<a name="line-50"></a>seen from this example:
<a name="line-51"></a>
<a name="line-52"></a>> normal :: [Inline] -> [Inline]
<a name="line-53"></a>> normal (Space : Space : xs) = Space : xs
<a name="line-54"></a>> normal (Emph xs : Emph ys : zs) = Emph (xs ++ ys) : zs
<a name="line-55"></a>> normal xs = xs
<a name="line-56"></a>>
<a name="line-57"></a>> myDoc :: Pandoc
<a name="line-58"></a>> myDoc = Pandoc (Meta {docTitle = [], docAuthors = [], docDate = []})
<a name="line-59"></a>> [Para [Str "Hi",Space,Emph [Str "world",Space],Emph [Space,Str "emphasized"]]]
<a name="line-60"></a>
<a name="line-61"></a>Here we want to use 'topDown' to lift @normal@ to @Pandoc -> Pandoc@.
<a name="line-62"></a>The top down strategy will collapse the two adjacent @Emph@s first, then
<a name="line-63"></a>collapse the resulting adjacent @Space@s, as desired. If we used 'bottomUp',
<a name="line-64"></a>we would end up with two adjacent @Space@s, since the contents of the
<a name="line-65"></a>two @Emph@ inlines would be processed before the @Emph@s were collapsed
<a name="line-66"></a>into one.
<a name="line-67"></a>
<a name="line-68"></a>> topDown normal myDoc ==
<a name="line-69"></a>> Pandoc (Meta {docTitle = [], docAuthors = [], docDate = []})
<a name="line-70"></a>> [Para [Str "Hi",Space,Emph [Str "world",Space,Str "emphasized"]]]
<a name="line-71"></a>>
<a name="line-72"></a>> bottomUp normal myDoc ==
<a name="line-73"></a>> Pandoc (Meta {docTitle = [], docAuthors = [], docDate = []})
<a name="line-74"></a>> [Para [Str "Hi",Space,Emph [Str "world",Space,Space,Str "emphasized"]]]
<a name="line-75"></a>
<a name="line-76"></a>'bottomUpM' is a monadic version of 'bottomUp'. It could be used,
<a name="line-77"></a>for example, to replace the contents of delimited code blocks with
<a name="line-78"></a>attribute @include=FILENAME@ with the contents of @FILENAME@:
<a name="line-79"></a>
<a name="line-80"></a>> doInclude :: Block -> IO Block
<a name="line-81"></a>> doInclude cb@(CodeBlock (id, classes, namevals) contents) =
<a name="line-82"></a>> case lookup "include" namevals of
<a name="line-83"></a>> Just f -> return . (CodeBlock (id, classes, namevals)) =<< readFile f
<a name="line-84"></a>> Nothing -> return cb
<a name="line-85"></a>> doInclude x = return x
<a name="line-86"></a>>
<a name="line-87"></a>> processIncludes :: Pandoc -> IO Pandoc
<a name="line-88"></a>> processIncludes = bottomUpM doInclude
<a name="line-89"></a>
<a name="line-90"></a>'queryWith' can be used, for example, to compile a list of URLs
<a name="line-91"></a>linked to in a document:
<a name="line-92"></a>
<a name="line-93"></a>> extractURL :: Inline -> [String]
<a name="line-94"></a>> extractURL (Link _ (u,_)) = [u]
<a name="line-95"></a>> extractURL (Image _ (u,_)) = [u]
<a name="line-96"></a>> extractURL _ = []
<a name="line-97"></a>>
<a name="line-98"></a>> extractURLs :: Pandoc -> [String]
<a name="line-99"></a>> extractURLs = queryWith extractURL
<a name="line-100"></a>
<a name="line-101"></a>-}</span>
<a name="line-102"></a><span class='hs-keyword'>module</span> <span class='hs-conid'>Text</span><span class='hs-varop'>.</span><span class='hs-conid'>Pandoc</span><span class='hs-varop'>.</span><span class='hs-conid'>Generic</span> <span class='hs-keyword'>where</span>
<a name="line-103"></a>
<a name="line-104"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Generics</span>
<a name="line-105"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Monoid</span>
<a name="line-106"></a>
<a name="line-107"></a><a name="bottomUp"></a><span class='hs-comment'>-- | Applies a transformation on @a@s to matching elements in a @b@,</span>
<a name="line-108"></a><span class='hs-comment'>-- moving from the bottom of the structure up.</span>
<a name="line-109"></a><span class='hs-definition'>bottomUp</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>Data</span> <span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-conid'>Data</span> <span class='hs-varid'>b</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=></span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>b</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>b</span>
<a name="line-110"></a><span class='hs-definition'>bottomUp</span> <span class='hs-varid'>f</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>everywhere</span> <span class='hs-layout'>(</span><span class='hs-varid'>mkT</span> <span class='hs-varid'>f</span><span class='hs-layout'>)</span>
<a name="line-111"></a>
<a name="line-112"></a><a name="topDown"></a><span class='hs-comment'>-- | Applies a transformation on @a@s to matching elements in a @b@,</span>
<a name="line-113"></a><span class='hs-comment'>-- moving from the top of the structure down.</span>
<a name="line-114"></a><span class='hs-definition'>topDown</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>Data</span> <span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-conid'>Data</span> <span class='hs-varid'>b</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=></span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>b</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>b</span>
<a name="line-115"></a><span class='hs-definition'>topDown</span> <span class='hs-varid'>f</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>everywhere'</span> <span class='hs-layout'>(</span><span class='hs-varid'>mkT</span> <span class='hs-varid'>f</span><span class='hs-layout'>)</span>
<a name="line-116"></a>
<a name="line-117"></a><a name="bottomUpM"></a><span class='hs-comment'>-- | Like 'bottomUp', but with monadic transformations.</span>
<a name="line-118"></a><span class='hs-definition'>bottomUpM</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span><span class='hs-layout'>,</span> <span class='hs-conid'>Data</span> <span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-conid'>Data</span> <span class='hs-varid'>b</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=></span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>b</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-varid'>b</span>
<a name="line-119"></a><span class='hs-definition'>bottomUpM</span> <span class='hs-varid'>f</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>everywhereM</span> <span class='hs-layout'>(</span><span class='hs-varid'>mkM</span> <span class='hs-varid'>f</span><span class='hs-layout'>)</span>
<a name="line-120"></a>
<a name="line-121"></a><a name="queryWith"></a><span class='hs-comment'>-- | Runs a query on matching @a@ elements in a @c@. The results</span>
<a name="line-122"></a><span class='hs-comment'>-- of the queries are combined using 'mappend'.</span>
<a name="line-123"></a><span class='hs-definition'>queryWith</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>Data</span> <span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-conid'>Monoid</span> <span class='hs-varid'>b</span><span class='hs-layout'>,</span> <span class='hs-conid'>Data</span> <span class='hs-varid'>c</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=></span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>b</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>c</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>b</span>
<a name="line-124"></a><span class='hs-definition'>queryWith</span> <span class='hs-varid'>f</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>everything</span> <span class='hs-varid'>mappend</span> <span class='hs-layout'>(</span><span class='hs-varid'>mempty</span> <span class='hs-varop'>`mkQ`</span> <span class='hs-varid'>f</span><span class='hs-layout'>)</span>
<a name="line-125"></a>
<a name="line-126"></a><a name="processWith"></a><span class='hs-comment'>{-# DEPRECATED processWith "Use bottomUp instead" #-}</span>
<a name="line-127"></a><span class='hs-comment'>-- | Deprecated synonym for @bottomUp@.</span>
<a name="line-128"></a><span class='hs-definition'>processWith</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>Data</span> <span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-conid'>Data</span> <span class='hs-varid'>b</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=></span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>b</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>b</span>
<a name="line-129"></a><span class='hs-definition'>processWith</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>bottomUp</span>
<a name="line-130"></a>
<a name="line-131"></a><a name="processWithM"></a><span class='hs-comment'>{-# DEPRECATED processWithM "Use bottomUpM instead" #-}</span>
<a name="line-132"></a><span class='hs-comment'>-- | Deprecated synonym for @bottomUpM@.</span>
<a name="line-133"></a><span class='hs-definition'>processWithM</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span><span class='hs-layout'>,</span> <span class='hs-conid'>Data</span> <span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-conid'>Data</span> <span class='hs-varid'>b</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=></span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>b</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-varid'>b</span>
<a name="line-134"></a><span class='hs-definition'>processWithM</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>bottomUpM</span>
<a name="line-135"></a>
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