Remove GFM modules; use CMarkGFM for both gfm and commonmark.

We no longer have a separate readGFM and writeGFM;
instead, we'll use readCommonMark and writeCommonMark
with githubExtensions.

It remains to implement these extensions conditionally.

Closes #3841.

2 files changed, 63 insertions, 191 deletions

diff --git a/src/Text/Pandoc/Readers/CommonMark.hs b/src/Text/Pandoc/Readers/CommonMark.hs
index a0ea9f3e8..9a67c8597 100644
--- a/src/Text/Pandoc/Readers/CommonMark.hs
+++ b/src/Text/Pandoc/Readers/CommonMark.hs
@@ -32,7 +32,7 @@ CommonMark is a strongly specified variant of Markdown: http://commonmark.org.
 module Text.Pandoc.Readers.CommonMark (readCommonMark)
 where
 
-import CMark
+import CMarkGFM
 import Data.List (groupBy)
 import Data.Text (Text, unpack)
 import Text.Pandoc.Class (PandocMonad)
@@ -42,10 +42,10 @@ import Text.Pandoc.Options
 -- | Parse a CommonMark formatted string into a 'Pandoc' structure.
 readCommonMark :: PandocMonad m => ReaderOptions -> Text -> m Pandoc
 readCommonMark opts s = return $
-  nodeToPandoc $ commonmarkToNode opts' s
-  where opts' = if extensionEnabled Ext_smart (readerExtensions opts)
-                   then [optSmart]
-                   else []
+  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) =
@@ -88,9 +88,64 @@ addBlock (Node _ (LIST listAttrs) nodes) =
         delim = case listDelim listAttrs of
                      PERIOD_DELIM -> Period
                      PAREN_DELIM  -> OneParen
-addBlock (Node _ ITEM _) = id -- handled in LIST
+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
 
@@ -121,6 +176,8 @@ 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) =
diff --git a/src/Text/Pandoc/Readers/GFM.hs b/src/Text/Pandoc/Readers/GFM.hs
deleted file mode 100644
index 1cdc47b98..000000000
--- a/src/Text/Pandoc/Readers/GFM.hs
+++ /dev/null
@@ -1,185 +0,0 @@
-{-
-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