Add support for the LineBlock element to writers

The following markup features are used to output the lines of the `LineBlock`
element:

  - AsciiDoc: a `[verse]` block,
  - ConTeXt: text surrounded by `\startlines` and `\endlines`,
  - HTML: `div` with an per-element style setting to interpret the content as
    pre-wrapped,
  - Markdown: line blocks if the `line_blocks` extension is enabled, a simple
    paragraph with hard linebreaks otherwise,
  - Org: VERSE block,
  - RST: a line block, and
  - all other formats: a paragraph, containing hard linebreaks between lines.

Custom lua writers should be updated to use the `LineBlock` element.

1 files changed, 11 insertions, 0 deletions

diff --git a/src/Text/Pandoc/Writers/Org.hs b/src/Text/Pandoc/Writers/Org.hs
index 96baacbb6..a74481171 100644
--- a/src/Text/Pandoc/Writers/Org.hs
+++ b/src/Text/Pandoc/Writers/Org.hs
@@ -164,6 +164,17 @@ blockToOrg (Para [Image attr txt (src,'f':'i':'g':':':tit)]) = do
 blockToOrg (Para inlines) = do
   contents <- inlineListToOrg inlines
   return $ contents <> blankline
+blockToOrg (LineBlock lns) = do
+  let splitStanza [] = []
+      splitStanza xs = case break (== mempty) xs of
+        (l, [])  -> l : []
+        (l, _:r) -> l : splitStanza r
+  let joinWithLinefeeds  = nowrap . mconcat . intersperse cr
+  let joinWithBlankLines = mconcat . intersperse blankline
+  let prettyfyStanza ls  = joinWithLinefeeds <$> mapM inlineListToOrg ls
+  contents <- joinWithBlankLines <$> mapM prettyfyStanza (splitStanza lns)
+  return $ blankline $$ "#+BEGIN_VERSE" $$
+           nest 2 contents $$ "#+END_VERSE" <> blankline
 blockToOrg (RawBlock "html" str) =
   return $ blankline $$ "#+BEGIN_HTML" $$
            nest 2 (text str) $$ "#+END_HTML" $$ blankline