HTML writer: In code blocks, change leading newlines to <br /> tags.

(Some browsers ignore them.)  Resolves Issue #71.
See http://six.pairlist.net/pipermail/markdown-discuss/2008-May/001297.html


git-svn-id: https://pandoc.googlecode.com/svn/trunk@1277 788f1e2b-df1e-0410-8736-df70ead52e1b

1 files changed, 8 insertions, 4 deletions

diff --git a/Text/Pandoc/Writers/HTML.hs b/Text/Pandoc/Writers/HTML.hs
index 6ada56ba2..bcf39ef9f 100644
--- a/Text/Pandoc/Writers/HTML.hs
+++ b/Text/Pandoc/Writers/HTML.hs
@@ -273,10 +273,14 @@ blockToHtml opts (RawHtml str) = return $ primHtml str
 blockToHtml opts (HorizontalRule) = return $ hr
 blockToHtml opts (CodeBlock attr@(_,classes,_) rawCode) = do
   case highlightHtml attr rawCode of
-         Left _  -> return $ pre ! (if null classes
-                                       then []
-                                       else [theclass $ unwords classes]) $ thecode << 
-                                            (rawCode ++ "\n")
+         Left _  -> -- change leading newlines into <br /> tags, because some
+                    -- browsers ignore leading newlines in pre blocks
+                    let (leadingBreaks, rawCode') = span (=='\n') rawCode
+                    in  return $ pre ! (if null classes
+                                           then []
+                                           else [theclass $ unwords classes]) $ thecode <<
+                                                (replicate (length leadingBreaks) br +++
+                                                [stringToHtml $ rawCode' ++ "\n"])
          Right h -> addToCSS defaultHighlightingCss >> return h
 blockToHtml opts (BlockQuote blocks) =
   -- in S5, treat list in blockquote specially