From 6c507a66cf007ee0d7739ef4c4217f6984db49ef Mon Sep 17 00:00:00 2001
From: John MacFarlane <jgm@berkeley.edu>
Date: Sun, 3 Oct 2021 19:11:12 -0700
Subject: Avoid bad wraps in markdown writer at the Doc Text level.

Previously we tried to do this at the Inline list level,
but it makes more sense to intervene on breaking spaces
at the Doc Text level.
---
 src/Text/Pandoc/Writers/Markdown/Inline.hs | 45 +++++++++++++++---------------
 1 file changed, 23 insertions(+), 22 deletions(-)

(limited to 'src')

diff --git a/src/Text/Pandoc/Writers/Markdown/Inline.hs b/src/Text/Pandoc/Writers/Markdown/Inline.hs
index 31c816e36..ab9674026 100644
--- a/src/Text/Pandoc/Writers/Markdown/Inline.hs
+++ b/src/Text/Pandoc/Writers/Markdown/Inline.hs
@@ -190,11 +190,13 @@ getReference attr label target = do
                                          (stKeys s) })
                     return lab'
 
+
+
 -- | Convert list of Pandoc inline elements to markdown.
 inlineListToMarkdown :: PandocMonad m => WriterOptions -> [Inline] -> MD m (Doc Text)
-inlineListToMarkdown opts lst = do
-  inlist <- asks envInList
-  go (if inlist then avoidBadWrapsInList lst else lst)
+inlineListToMarkdown opts ils = do
+    inlist <- asks envInList
+    avoidBadWraps inlist <$> go ils
   where go [] = return empty
         go (x@Math{}:y@(Str t):zs)
           | T.all isDigit (T.take 1 t) -- starts with digit -- see #7058
@@ -235,26 +237,25 @@ inlineListToMarkdown opts lst = do
                     fmap (iMark <>) (go is)
                 thead = fmap fst . T.uncons
 
-isSp :: Inline -> Bool
-isSp Space     = True
-isSp SoftBreak = True
-isSp _         = False
+-- Remove breaking spaces that might cause bad wraps.
+avoidBadWraps :: Bool -> Doc Text -> Doc Text
+avoidBadWraps inListItem = go . toList
+ where
+  go [] = mempty
+  go (BreakingSpace : Text len t : BreakingSpace : xs)
+    = case T.uncons t of
+        Just (c,t')
+          | c == '>'
+             || ((c == '-' || c == '*' || c == '+') && T.null t')
+             || (inListItem && isOrderedListMarker t)
+             || (t == "1." || t == "1)")
+            -> Text (len + 1) (" " <> t) <> go (BreakingSpace : xs)
+        _   -> BreakingSpace <> Text len t <> go (BreakingSpace : xs)
+  go (x:xs) = x <> go xs
 
-avoidBadWrapsInList :: [Inline] -> [Inline]
-avoidBadWrapsInList [] = []
-avoidBadWrapsInList (s:Str (T.uncons -> Just ('>',cs)):xs) | isSp s =
-  Str (" >" <> cs) : avoidBadWrapsInList xs
-avoidBadWrapsInList [s, Str (T.uncons -> Just (c, cs))]
-  | T.null cs && isSp s && c `elem` ['-','*','+'] = [Str $ T.pack [' ', c]]
-avoidBadWrapsInList (s:Str (T.uncons -> Just (c, cs)):Space:xs)
-  | T.null cs && isSp s && c `elem` ['-','*','+'] =
-    Str (T.pack [' ', c]) : Space : avoidBadWrapsInList xs
-avoidBadWrapsInList (s:Str cs:Space:xs)
-  | isSp s && isOrderedListMarker cs =
-    Str (" " <> cs) : Space : avoidBadWrapsInList xs
-avoidBadWrapsInList [s, Str cs]
-  | isSp s && isOrderedListMarker cs = [Str $ " " <> cs]
-avoidBadWrapsInList (x:xs) = x : avoidBadWrapsInList xs
+  toList (Concat (Concat a b) c) = toList (Concat a (Concat b c))
+  toList (Concat a b) = a : toList b
+  toList x = [x]
 
 isOrderedListMarker :: Text -> Bool
 isOrderedListMarker xs = not (T.null xs) && (T.last xs `elem` ['.',')']) &&
-- 
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