Changes to literate haskell options.

- Removed writerLiterateHaskell from WriterOptions.
- Removed readerLiterateHaskell from ReaderOptions.
- Added Ext_literate_haskell to Extensions.  Test for this
  instead of the above.
- Removed failUnlessLHS from Shared.

Note:  At this point, +lhs and .lhs extension no longer has any effect.
Need to fix.

4 files changed, 6 insertions, 9 deletions

diff --git a/src/Text/Pandoc/Writers/HTML.hs b/src/Text/Pandoc/Writers/HTML.hs
index 9a15e4bd3..c6c4a8fd7 100644
--- a/src/Text/Pandoc/Writers/HTML.hs
+++ b/src/Text/Pandoc/Writers/HTML.hs
@@ -397,7 +397,7 @@ blockToHtml _ (RawBlock "html" str) = return $ preEscapedString str
 blockToHtml _ (RawBlock _ _) = return mempty
 blockToHtml opts (HorizontalRule) = return $ if writerHtml5 opts then H5.hr else H.hr
 blockToHtml opts (CodeBlock (id',classes,keyvals) rawCode) = do
-  let tolhs = writerLiterateHaskell opts &&
+  let tolhs = isEnabled Ext_literate_haskell opts &&
                 any (\c -> map toLower c == "haskell") classes &&
                 any (\c -> map toLower c == "literate") classes
       classes' = if tolhs
diff --git a/src/Text/Pandoc/Writers/LaTeX.hs b/src/Text/Pandoc/Writers/LaTeX.hs
index e4788ab06..abbbd4d01 100644
--- a/src/Text/Pandoc/Writers/LaTeX.hs
+++ b/src/Text/Pandoc/Writers/LaTeX.hs
@@ -290,7 +290,7 @@ blockToLaTeX (BlockQuote lst) = do
 blockToLaTeX (CodeBlock (_,classes,keyvalAttr) str) = do
   opts <- gets stOptions
   case () of
-     _ | writerLiterateHaskell opts && "haskell" `elem` classes &&
+     _ | isEnabled Ext_literate_haskell opts && "haskell" `elem` classes &&
          "literate" `elem` classes                      -> lhsCodeBlock
        | writerListings opts                            -> listingsCodeBlock
        | writerHighlight opts && not (null classes)     -> highlightedCodeBlock
diff --git a/src/Text/Pandoc/Writers/Markdown.hs b/src/Text/Pandoc/Writers/Markdown.hs
index 8e608ea3d..52805c1aa 100644
--- a/src/Text/Pandoc/Writers/Markdown.hs
+++ b/src/Text/Pandoc/Writers/Markdown.hs
@@ -49,9 +49,6 @@ data WriterState = WriterState { stNotes :: Notes
                                , stRefs :: Refs
                                , stPlain :: Bool }
 
-isEnabled :: Extension -> WriterOptions -> Bool
-isEnabled ext opts = ext `Set.member` (writerExtensions opts)
-
 -- | Convert Pandoc to Markdown.
 writeMarkdown :: WriterOptions -> Pandoc -> String
 writeMarkdown opts document =
@@ -255,12 +252,12 @@ blockToMarkdown opts (Header level inlines) = do
                   contents <> cr <> text (replicate (offset contents) '-') <>
                   blankline
             -- ghc interprets '#' characters in column 1 as linenum specifiers.
-            _ | stPlain st || writerLiterateHaskell opts ->
+            _ | stPlain st || isEnabled Ext_literate_haskell opts ->
                 contents <> blankline
             _ -> text (replicate level '#') <> space <> contents <> blankline
 blockToMarkdown opts (CodeBlock (_,classes,_) str)
   | "haskell" `elem` classes && "literate" `elem` classes &&
-    writerLiterateHaskell opts =
+    isEnabled Ext_literate_haskell opts =
   return $ prefixed "> " (text str) <> blankline
 blockToMarkdown opts (CodeBlock attribs str) = return $
   if isEnabled Ext_delimited_code_blocks opts && attribs /= nullAttr
@@ -274,7 +271,7 @@ blockToMarkdown opts (BlockQuote blocks) = do
   st <- get
   -- if we're writing literate haskell, put a space before the bird tracks
   -- so they won't be interpreted as lhs...
-  let leader = if writerLiterateHaskell opts
+  let leader = if isEnabled Ext_literate_haskell opts
                   then " > "
                   else if stPlain st
                           then "  "
diff --git a/src/Text/Pandoc/Writers/RST.hs b/src/Text/Pandoc/Writers/RST.hs
index 0c46cb0bc..5b0b5a414 100644
--- a/src/Text/Pandoc/Writers/RST.hs
+++ b/src/Text/Pandoc/Writers/RST.hs
@@ -164,7 +164,7 @@ blockToRST (CodeBlock (_,classes,_) str) = do
   opts <- stOptions <$> get
   let tabstop = writerTabStop opts
   if "haskell" `elem` classes && "literate" `elem` classes &&
-                  writerLiterateHaskell opts
+                  isEnabled Ext_literate_haskell opts
      then return $ prefixed "> " (text str) $$ blankline
      else return $ "::" $+$ nest tabstop (text str) $$ blankline
 blockToRST (BlockQuote blocks) = do