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{-
Copyright (C) 2017 John MacFarlane <jgm@berkeley.edu>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
-}
{- |
Module : Text.Pandoc.Readers.GFM
Copyright : Copyright (C) 2017 John MacFarlane
License : GNU GPL, version 2 or above
Maintainer : John MacFarlane <jgm@berkeley.edu>
Stability : alpha
Portability : portable
Conversion of GitHub flavored CommonMark text to 'Pandoc' document.
CommonMark is a strongly specified variant of Markdown: http://commonmark.org.
-}
module Text.Pandoc.Readers.GFM (readGFM)
where
import CMarkGFM
import Data.List (groupBy)
import Data.Text (Text, unpack)
import Text.Pandoc.Class (PandocMonad)
import Text.Pandoc.Definition
import Text.Pandoc.Options
-- | Parse a CommonMark formatted string into a 'Pandoc' structure.
readGFM :: PandocMonad m => ReaderOptions -> Text -> m Pandoc
readGFM opts s = return $
nodeToPandoc $ commonmarkToNode opts' exts s
where opts' = [optSmart | enabled Ext_smart]
exts = [extStrikethrough, extTable, extAutolink]
enabled x = extensionEnabled x (readerExtensions opts)
nodeToPandoc :: Node -> Pandoc
nodeToPandoc (Node _ DOCUMENT nodes) =
Pandoc nullMeta $ foldr addBlock [] nodes
nodeToPandoc n = -- shouldn't happen
Pandoc nullMeta $ foldr addBlock [] [n]
addBlocks :: [Node] -> [Block]
addBlocks = foldr addBlock []
addBlock :: Node -> [Block] -> [Block]
addBlock (Node _ PARAGRAPH nodes) =
(Para (addInlines nodes) :)
addBlock (Node _ THEMATIC_BREAK _) =
(HorizontalRule :)
addBlock (Node _ BLOCK_QUOTE nodes) =
(BlockQuote (addBlocks nodes) :)
addBlock (Node _ (HTML_BLOCK t) _) =
(RawBlock (Format "html") (unpack t) :)
-- Note: the cmark parser will never generate CUSTOM_BLOCK,
-- so we don't need to handle it:
addBlock (Node _ (CUSTOM_BLOCK _onEnter _onExit) _nodes) =
id
addBlock (Node _ (CODE_BLOCK info t) _) =
(CodeBlock ("", take 1 (words (unpack info)), []) (unpack t) :)
addBlock (Node _ (HEADING lev) nodes) =
(Header lev ("",[],[]) (addInlines nodes) :)
addBlock (Node _ (LIST listAttrs) nodes) =
(constructor (map (setTightness . addBlocks . children) nodes) :)
where constructor = case listType listAttrs of
BULLET_LIST -> BulletList
ORDERED_LIST -> OrderedList
(start, DefaultStyle, delim)
start = listStart listAttrs
setTightness = if listTight listAttrs
then map paraToPlain
else id
paraToPlain (Para xs) = Plain (xs)
paraToPlain x = x
delim = case listDelim listAttrs of
PERIOD_DELIM -> Period
PAREN_DELIM -> OneParen
addBlock (Node _ (TABLE alignments) nodes) = do
(Table [] aligns widths headers rows :)
where aligns = map fromTableCellAlignment alignments
fromTableCellAlignment NoAlignment = AlignDefault
fromTableCellAlignment LeftAligned = AlignLeft
fromTableCellAlignment RightAligned = AlignRight
fromTableCellAlignment CenterAligned = AlignCenter
widths = replicate numcols 0.0
numcols = if null rows'
then 0
else maximum $ map length rows'
rows' = map toRow $ filter isRow nodes
(headers, rows) = case rows' of
(h:rs) -> (h, rs)
[] -> ([], [])
isRow (Node _ TABLE_ROW _) = True
isRow _ = False
isCell (Node _ TABLE_CELL _) = True
isCell _ = False
toRow (Node _ TABLE_ROW ns) = map toCell $ filter isCell ns
toRow (Node _ t _) = error $ "toRow encountered non-row " ++ show t
toCell (Node _ TABLE_CELL []) = []
toCell (Node _ TABLE_CELL (n:ns))
| isBlockNode n = addBlocks (n:ns)
| otherwise = [Plain (addInlines (n:ns))]
toCell (Node _ t _) = error $ "toCell encountered non-cell " ++ show t
addBlock (Node _ TABLE_ROW _) = id -- handled in TABLE
addBlock (Node _ TABLE_CELL _) = id -- handled in TABLE
addBlock _ = id
isBlockNode :: Node -> Bool
isBlockNode (Node _ nodetype _) =
case nodetype of
DOCUMENT -> True
THEMATIC_BREAK -> True
PARAGRAPH -> True
BLOCK_QUOTE -> True
HTML_BLOCK _ -> True
CUSTOM_BLOCK _ _ -> True
CODE_BLOCK _ _ -> True
HEADING _ -> True
LIST _ -> True
ITEM -> True
TEXT _ -> False
SOFTBREAK -> False
LINEBREAK -> False
HTML_INLINE _ -> False
CUSTOM_INLINE _ _ -> False
CODE _ -> False
EMPH -> False
STRONG -> False
LINK _ _ -> False
IMAGE _ _ -> False
STRIKETHROUGH -> False
TABLE _ -> False
TABLE_ROW -> False
TABLE_CELL -> False
children :: Node -> [Node]
children (Node _ _ ns) = ns
addInlines :: [Node] -> [Inline]
addInlines = foldr addInline []
addInline :: Node -> [Inline] -> [Inline]
addInline (Node _ (TEXT t) _) = (map toinl clumps ++)
where raw = unpack t
clumps = groupBy samekind raw
samekind ' ' ' ' = True
samekind ' ' _ = False
samekind _ ' ' = False
samekind _ _ = True
toinl (' ':_) = Space
toinl xs = Str xs
addInline (Node _ LINEBREAK _) = (LineBreak :)
addInline (Node _ SOFTBREAK _) = (SoftBreak :)
addInline (Node _ (HTML_INLINE t) _) =
(RawInline (Format "html") (unpack t) :)
-- Note: the cmark parser will never generate CUSTOM_BLOCK,
-- so we don't need to handle it:
addInline (Node _ (CUSTOM_INLINE _onEnter _onExit) _nodes) =
id
addInline (Node _ (CODE t) _) =
(Code ("",[],[]) (unpack t) :)
addInline (Node _ EMPH nodes) =
(Emph (addInlines nodes) :)
addInline (Node _ STRONG nodes) =
(Strong (addInlines nodes) :)
addInline (Node _ STRIKETHROUGH nodes) =
(Strikeout (addInlines nodes) :)
addInline (Node _ (LINK url title) nodes) =
(Link nullAttr (addInlines nodes) (unpack url, unpack title) :)
addInline (Node _ (IMAGE url title) nodes) =
(Image nullAttr (addInlines nodes) (unpack url, unpack title) :)
addInline _ = id
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