Muse writer: output tables as grid tables if they have multi-line cells

src/Text/Pandoc/Writers/Muse.hs

@@ -49,6 +49,7 @@ import Control.Monad.State.Strict
 import Data.Char (isAlphaNum, isAsciiLower, isAsciiUpper, isDigit, isSpace)
 import Data.Default
 import Data.List (intersperse, isInfixOf, transpose)
+import Data.Monoid (Any (..))
 import qualified Data.Set as Set
 import Data.Text (Text)
 import System.FilePath (takeExtension)
@@ -61,6 +62,7 @@ import Text.Pandoc.Shared
 import Text.Pandoc.Templates (renderTemplate')
 import Text.Pandoc.Writers.Math
 import Text.Pandoc.Writers.Shared
+import Text.Pandoc.Walk
 
 type Notes = [[Block]]
 
@@ -276,7 +278,7 @@ blockToMuse (Header level (ident,_,_) inlines) = do
 -- https://www.gnu.org/software/emacs-muse/manual/muse.html#Horizontal-Rules-and-Anchors
 blockToMuse HorizontalRule = return $ blankline $$ "----" $$ blankline
 blockToMuse (Table caption aligns widths headers rows) =
-  if all (== 0.0) widths && length widths > 1
+  if isSimple && numcols > 1
     then simpleTable caption headers rows
     else do
       opts <- asks envOptions
@@ -284,6 +286,16 @@ blockToMuse (Table caption aligns widths headers rows) =
   where
     blocksToDoc opts blocks =
       local (\env -> env { envOptions = opts }) $ blockListToMuse blocks
+    numcols = maximum (length aligns : length widths : map length (headers:rows))
+    hasSimpleCells = all isSimpleCell (concat (headers:rows))
+    isLineBreak LineBreak = Any True
+    isLineBreak _         = Any False
+    hasLineBreak = getAny . query isLineBreak
+    isSimple = hasSimpleCells && all (== 0) widths
+    isSimpleCell [Plain ils] = not (hasLineBreak ils)
+    isSimpleCell [Para ils ] = not (hasLineBreak ils)
+    isSimpleCell []          = True
+    isSimpleCell _           = False
 blockToMuse (Div _ bs) = flatBlockListToMuse bs
 blockToMuse Null = return empty