(wip) Add support for @since (closes #26)

3 files changed, 49 insertions, 12 deletions

diff --git a/haddock-library/src/Documentation/Haddock/Parser.hs b/haddock-library/src/Documentation/Haddock/Parser.hs
index c323ce0c..1cc277b8 100644
--- a/haddock-library/src/Documentation/Haddock/Parser.hs
+++ b/haddock-library/src/Documentation/Haddock/Parser.hs
@@ -78,7 +78,7 @@ overIdentifier f d = g d
     g (DocExamples x) = DocExamples x
     g (DocHeader (Header l x)) = DocHeader . Header l $ g x
 
-parse :: Parser a -> BS.ByteString -> a
+parse :: Parser a -> BS.ByteString -> (ParserState, a)
 parse p = either err id . parseOnly (p <* endOfInput)
   where
     err = error . ("Haddock.Parser.parse: " ++)
@@ -86,19 +86,27 @@ parse p = either err id . parseOnly (p <* endOfInput)
 -- | Main entry point to the parser. Appends the newline character
 -- to the input string.
 parseParas :: String -- ^ String to parse
-           -> DocH mod Identifier
-parseParas = parse (p <* skipSpace) . encodeUtf8 . (++ "\n")
+           -> (Maybe Version, DocH mod Identifier)
+parseParas input = case parseParasState input of
+  (state, a) -> (parserStateSince state, a)
+
+parseParasState :: String -> (ParserState, DocH mod Identifier)
+parseParasState = parse (p <* skipSpace) . encodeUtf8 . (++ "\n")
   where
     p :: Parser (DocH mod Identifier)
     p = docConcat <$> paragraph `sepBy` many (skipHorizontalSpace *> "\n")
 
+parseParagraphs :: String -> Parser (DocH mod Identifier)
+parseParagraphs input = case parseParasState input of
+  (state, a) -> setParserState state >> return a
+
 -- | Parse a text paragraph. Actually just a wrapper over 'parseStringBS' which
 -- drops leading whitespace and encodes the string to UTF8 first.
 parseString :: String -> DocH mod Identifier
 parseString = parseStringBS . encodeUtf8 . dropWhile isSpace
 
 parseStringBS :: BS.ByteString -> DocH mod Identifier
-parseStringBS = parse p
+parseStringBS = snd . parse p
   where
     p :: Parser (DocH mod Identifier)
     p = docConcat <$> many (monospace <|> anchor <|> identifier <|> moduleName
@@ -217,7 +225,8 @@ markdownImage = fromHyperlink <$> ("!" *> linkParser)
 -- | Paragraph parser, called by 'parseParas'.
 paragraph :: Parser (DocH mod Identifier)
 paragraph = examples <|> skipSpace *> (
-      unorderedList
+      since
+  <|> unorderedList
   <|> orderedList
   <|> birdtracks
   <|> codeblock
@@ -228,6 +237,11 @@ paragraph = examples <|> skipSpace *> (
   <|> docParagraph <$> textParagraph
   )
 
+since :: Parser (DocH mod a)
+since = ("@since " *> version <* skipHorizontalSpace <* endOfLine) >>= setSince >> return DocEmpty
+  where
+    version = decimal `sepBy1'` "."
+
 -- | Headers inside the comment denoted with @=@ signs, up to 6 levels
 -- deep.
 --
@@ -334,7 +348,7 @@ moreContent item = first . (:) <$> nonEmptyLine <*> more item
 -- | Parses an indented paragraph.
 -- The indentation is 4 spaces.
 indentedParagraphs :: Parser (DocH mod Identifier)
-indentedParagraphs = parseParas . concat <$> dropFrontOfPara "    "
+indentedParagraphs = (concat <$> dropFrontOfPara "    ") >>= parseParagraphs
 
 -- | Grab as many fully indented paragraphs as we can.
 dropFrontOfPara :: Parser BS.ByteString -> Parser [String]
diff --git a/haddock-library/src/Documentation/Haddock/Parser/Monad.hs b/haddock-library/src/Documentation/Haddock/Parser/Monad.hs
index 19edce04..a421c58c 100644
--- a/haddock-library/src/Documentation/Haddock/Parser/Monad.hs
+++ b/haddock-library/src/Documentation/Haddock/Parser/Monad.hs
@@ -1,4 +1,4 @@
-{-# LANGUAGE GeneralizedNewtypeDeriving #-}
+{-# LANGUAGE GeneralizedNewtypeDeriving, TypeFamilies #-}
 module Documentation.Haddock.Parser.Monad (
   module Documentation.Haddock.Parser.Monad
 , Attoparsec.isDigit
@@ -34,17 +34,38 @@ import           Data.String
 import           Data.ByteString (ByteString)
 import qualified Data.ByteString.Lazy as LB
 import qualified Data.Attoparsec.ByteString.Char8 as Attoparsec
+import           Control.Monad.Trans.State
+import qualified Control.Monad.Trans.Class as Trans
 import           Data.Word
 import           Data.Bits
+import           Data.Tuple
 
-newtype Parser a = Parser (Attoparsec.Parser a)
-  deriving (Functor, Applicative, Alternative, Monad, MonadPlus, IsString)
+import           Documentation.Haddock.Types (Version)
 
-parseOnly :: Parser a -> ByteString -> Either String a
-parseOnly (Parser p) = Attoparsec.parseOnly p
+data ParserState = ParserState {
+  parserStateSince :: Maybe Version
+} deriving (Eq, Show)
+
+initialParserState :: ParserState
+initialParserState = ParserState Nothing
+
+newtype Parser a = Parser (StateT ParserState Attoparsec.Parser a)
+  deriving (Functor, Applicative, Alternative, Monad, MonadPlus)
+
+instance (a ~ ByteString) => IsString (Parser a) where
+  fromString = lift . fromString
+
+parseOnly :: Parser a -> ByteString -> Either String (ParserState, a)
+parseOnly (Parser p) = fmap swap . Attoparsec.parseOnly (runStateT p initialParserState)
 
 lift :: Attoparsec.Parser a -> Parser a
-lift = Parser
+lift = Parser . Trans.lift
+
+setParserState :: ParserState -> Parser ()
+setParserState = Parser . put
+
+setSince :: Version -> Parser ()
+setSince since = Parser $ modify (\st -> st {parserStateSince = Just since})
 
 char :: Char -> Parser Char
 char = lift . Attoparsec.char
diff --git a/haddock-library/src/Documentation/Haddock/Types.hs b/haddock-library/src/Documentation/Haddock/Types.hs
index b2d28be9..92ddeb7e 100644
--- a/haddock-library/src/Documentation/Haddock/Types.hs
+++ b/haddock-library/src/Documentation/Haddock/Types.hs
@@ -17,6 +17,8 @@ module Documentation.Haddock.Types where
 import Data.Foldable
 import Data.Traversable
 
+type Version = [Int]
+
 data Hyperlink = Hyperlink
   { hyperlinkUrl   :: String
   , hyperlinkLabel :: Maybe String