Allow for headings inside function documentation.

LaTeX will treat the h3-h6 headings the same as we'd have to hack the
style file heavily otherwise and it would make the headings tiny
anyway.

Hoogle upstream said they will put in the functionality on their end.

Conflicts:
	src/Haddock/Interface/Rename.hs
	src/Haddock/Types.hs
	test/Haddock/ParserSpec.hs

1 files changed, 12 insertions, 2 deletions

diff --git a/src/Haddock/Parser.hs b/src/Haddock/Parser.hs
index 58d047f7..0d24cf17 100644
--- a/src/Haddock/Parser.hs
+++ b/src/Haddock/Parser.hs
@@ -14,7 +14,7 @@ module Haddock.Parser (parseString, parseParas, parseStringMaybe, parseParasMayb
 import           Prelude hiding (takeWhile)
 import           Control.Monad (void, mfilter)
 import           Control.Applicative
-import           Data.Attoparsec.ByteString.Char8 hiding (parse, take, string, endOfLine)
+import           Data.Attoparsec.ByteString.Char8 hiding (parse, take, endOfLine)
 import qualified Data.ByteString.Char8 as BS
 import           Data.Char (chr, isAsciiUpper)
 import           Data.List (stripPrefix, intercalate)
@@ -168,7 +168,17 @@ picture = DocPic . makeLabeled Picture . decodeUtf8
 -- | Paragraph parser, called by 'parseParas'.
 paragraph :: DynFlags -> Parser (Doc RdrName)
 paragraph d = examples <|> skipSpace *> (list d <|> birdtracks <|> codeblock d
-                                         <|> property <|> textParagraph d)
+                                         <|> property <|> header d
+                                         <|> textParagraph d)
+
+header :: DynFlags -> Parser (Doc RdrName)
+header d = do
+  let psers = map (string . encodeUtf8 . concat . flip replicate "=") [6, 5 .. 1]
+      pser = foldl1 (<|>) psers
+  delim <- decodeUtf8 <$> pser
+  line <- skipHorizontalSpace *> nonEmptyLine >>= return . parseString d
+  rest <- paragraph d <|> return mempty
+  return $ docAppend (DocParagraph (DocHeader (Header (length delim) line))) rest
 
 textParagraph :: DynFlags -> Parser (Doc RdrName)
 textParagraph d = docParagraph . parseString d . intercalate "\n" <$> many1 nonEmptyLine