+ Improved text wrapping algorithm in markdown, docbook, and RST writers.

  LineBreaks no longer cause ugly wrapping in Markdown output.
+ Replaced splitBySpace with the more general, polymorphic function
  splitBy (in Text/Pandoc/Shared).


git-svn-id: https://pandoc.googlecode.com/svn/trunk@411 788f1e2b-df1e-0410-8736-df70ead52e1b

4 files changed, 20 insertions, 11 deletions

diff --git a/src/Text/Pandoc/Shared.hs b/src/Text/Pandoc/Shared.hs
index adc2621f3..d4687b10e 100644
--- a/src/Text/Pandoc/Shared.hs
+++ b/src/Text/Pandoc/Shared.hs
@@ -52,7 +52,7 @@ module Text.Pandoc.Shared (
                      -- * Pandoc block list processing
                      consolidateList,
                      isNoteBlock,
-                     splitBySpace,
+                     splitBy,
                      normalizeSpaces,
                      compactify,
                      generateReference,
@@ -274,10 +274,13 @@ removeTrailingSpace = reverse . removeLeadingSpace . reverse
 stripFirstAndLast str =
   drop 1 $ take ((length str) - 1) str
 
--- | Split list of inlines into groups separated by a space.
-splitBySpace :: [Inline] -> [[Inline]]
-splitBySpace lst = filter (\a -> (/= Space) (head a)) 
-                     (groupBy (\a b -> (/= Space) a && (/= Space) b) lst)
+-- | Split list into groups separated by sep.
+splitBy :: (Eq a) => a -> [a] -> [[a]]
+splitBy _ [] = []
+splitBy sep lst = 
+  let (first, rest) = break (== sep) lst
+      rest'         = dropWhile (== sep) rest in
+  first:(splitBy sep rest')
 
 -- | Normalize a list of inline elements: remove leading and trailing
 -- @Space@ elements, and collapse double @Space@s into singles.
diff --git a/src/Text/Pandoc/Writers/Docbook.hs b/src/Text/Pandoc/Writers/Docbook.hs
index 8ccf84f30..5f6f1c8b1 100644
--- a/src/Text/Pandoc/Writers/Docbook.hs
+++ b/src/Text/Pandoc/Writers/Docbook.hs
@@ -176,7 +176,7 @@ cdata str = text $ "<![CDATA[" ++ str ++ "]]>"
 
 -- | Take list of inline elements and return wrapped doc.
 wrap :: WriterOptions -> [Inline] -> Doc
-wrap options lst = fsep $ map (hcat . (map (inlineToDocbook options))) (splitBySpace lst)
+wrap options lst = fsep $ map (inlinesToDocbook options) (splitBy Space lst)
 
 -- | Escape a string for XML (with "smart" option if specified).
 stringToXML :: WriterOptions -> String -> String
diff --git a/src/Text/Pandoc/Writers/Markdown.hs b/src/Text/Pandoc/Writers/Markdown.hs
index bfebc71fe..c1d50c2ef 100644
--- a/src/Text/Pandoc/Writers/Markdown.hs
+++ b/src/Text/Pandoc/Writers/Markdown.hs
@@ -58,8 +58,13 @@ escapeLinkTitle = gsub "\"" "\\\\\""
 
 -- | Take list of inline elements and return wrapped doc.
 wrappedMarkdown :: [Inline] -> Doc
-wrappedMarkdown lst = fsep $ 
-                      map (fcat . (map inlineToMarkdown)) (splitBySpace lst) 
+wrappedMarkdown lst = 
+  let wrapSection sec = fsep $ map inlineListToMarkdown $ (splitBy Space sec) 
+      wrappedSecs     = map wrapSection $ splitBy LineBreak lst
+      wrappedSecs'    = foldr (\s rest -> if not (null rest)
+                                            then (s <> text "  "):rest
+                                            else s:rest) [] wrappedSecs  in
+  vcat wrappedSecs'
 
 -- | Insert Blank block between key and non-key
 formatKeys :: [Block] -> [Block]
diff --git a/src/Text/Pandoc/Writers/RST.hs b/src/Text/Pandoc/Writers/RST.hs
index 8b2563eb4..9184e0200 100644
--- a/src/Text/Pandoc/Writers/RST.hs
+++ b/src/Text/Pandoc/Writers/RST.hs
@@ -59,9 +59,10 @@ escapeString = backslashEscape "`\\|*_"
 -- and another containing references.
 wrappedRST :: [Inline] -> (Doc, Doc)
 wrappedRST lst = 
-  let words = splitBySpace lst in
-  ( fsep $ map (fcat . (map (fst . inlineToRST))) words, 
-    vcat (map (snd . inlineToRST) lst) )
+  let wrap_section sec = fsep $ map (fst . inlineListToRST) $ 
+                         (splitBy Space sec) in
+  ((vcat $ map wrap_section $ (splitBy LineBreak lst)),
+  vcat $ map (snd . inlineToRST) lst)
 
 -- | Remove reference keys, and make sure there are blanks before each list.
 reformatBlocks :: [Block] -> [Block]