Allow the parser to spit out meta-info

Currently we only use it only for ‘since’ annotations but with these
patches it should be fairly simple to add new attributes if we wish to.

Closes #26. It seems to work fine but due to 7.10 rush I don't have the
chance to do more exhaustive testing right now. The way the meta is
output (emphasis at the end of the whole comment) is fairly arbitrary
and subject to bikeshedding.

Note that this makes test for Bug310 fail due to interface version bump:
it can't find the docs for base with this interface version so it fails.
There is not much we can do to help this because it tests for ’built-in’
identifier, not something we can provide ourselves.

5 files changed, 68 insertions, 45 deletions

diff --git a/haddock-api/src/Haddock/Backends/Hoogle.hs b/haddock-api/src/Haddock/Backends/Hoogle.hs
index 628e1cd0..79ada0f7 100644
--- a/haddock-api/src/Haddock/Backends/Hoogle.hs
+++ b/haddock-api/src/Haddock/Backends/Hoogle.hs
@@ -207,12 +207,14 @@ ppCtor dflags dat subdocs con = lookupCon dflags subdocs (con_name con)
 -- DOCUMENTATION
 
 ppDocumentation :: Outputable o => DynFlags -> Documentation o -> [String]
-ppDocumentation dflags (Documentation d w) = doc dflags d ++ doc dflags w
+ppDocumentation dflags (Documentation d w) = mdoc dflags d ++ doc dflags w
 
 
 doc :: Outputable o => DynFlags -> Maybe (Doc o) -> [String]
 doc dflags = docWith dflags ""
 
+mdoc :: Outputable o => DynFlags -> Maybe (MDoc o) -> [String]
+mdoc dflags = docWith dflags "" . fmap _doc
 
 docWith :: Outputable o => DynFlags -> String -> Maybe (Doc o) -> [String]
 docWith _ [] Nothing = []
diff --git a/haddock-api/src/Haddock/Backends/LaTeX.hs b/haddock-api/src/Haddock/Backends/LaTeX.hs
index 7b72c030..f540527b 100644
--- a/haddock-api/src/Haddock/Backends/LaTeX.hs
+++ b/haddock-api/src/Haddock/Backends/LaTeX.hs
@@ -234,7 +234,7 @@ processExport (ExportNoDecl y subs)
 processExport (ExportModule mdl)
   = declWithDoc (text "module" <+> text (moduleString mdl)) Nothing
 processExport (ExportDoc doc)
-  = docToLaTeX doc
+  = docToLaTeX $ _doc doc
 
 
 ppDocGroup :: Int -> LaTeX -> LaTeX
@@ -393,7 +393,7 @@ ppTypeOrFunSig _ _ typ (doc, argDocs) (pref1, pref2, sep0)
   where
      do_largs n leader (L _ t) = do_args n leader t
 
-     arg_doc n = rDoc (Map.lookup n argDocs)
+     arg_doc n = rDoc . fmap _doc $ Map.lookup n argDocs
 
      do_args :: Int -> LaTeX -> (HsType DocName) -> LaTeX
      do_args n leader (HsForAllTy Explicit tvs lctxt ltype)
@@ -553,7 +553,7 @@ isUndocdInstance _ = Nothing
 -- style.
 ppDocInstance :: Bool -> DocInstance DocName -> LaTeX
 ppDocInstance unicode (instHead, doc) =
-  declWithDoc (ppInstDecl unicode instHead) (fmap docToLaTeX doc)
+  declWithDoc (ppInstDecl unicode instHead) (fmap docToLaTeX $ fmap _doc doc)
 
 
 ppInstDecl :: Bool -> InstHead DocName -> LaTeX
@@ -674,7 +674,8 @@ ppSideBySideConstr subdocs unicode leader (L _ con) =
     forall  = con_explicit con
     -- don't use "con_doc con", in case it's reconstructed from a .hi file,
     -- or also because we want Haddock to do the doc-parsing, not GHC.
-    mbDoc = lookup (unLoc $ con_name con) subdocs >>= combineDocumentation . fst
+    mbDoc = lookup (unLoc $ con_name con) subdocs
+            >>= fmap _doc . combineDocumentation . fst
     mkFunTy a b = noLoc (HsFunTy a b)
 
 
@@ -684,7 +685,7 @@ ppSideBySideField subdocs unicode (ConDeclField (L _ name) ltype _) =
     <+> dcolon unicode <+> ppLType unicode ltype) <-> rDoc mbDoc
   where
     -- don't use cd_fld_doc for same reason we don't use con_doc above
-    mbDoc = lookup name subdocs >>= combineDocumentation . fst
+    mbDoc = lookup name subdocs >>= fmap _doc . combineDocumentation . fst
 
 -- {-
 -- ppHsFullConstr :: HsConDecl -> LaTeX
@@ -1105,7 +1106,7 @@ docToLaTeX doc = markup latexMarkup doc Plain
 
 
 documentationToLaTeX :: Documentation DocName -> Maybe LaTeX
-documentationToLaTeX = fmap docToLaTeX . combineDocumentation
+documentationToLaTeX = fmap docToLaTeX . fmap _doc . combineDocumentation
 
 
 rdrDocToLaTeX :: Doc RdrName -> LaTeX
diff --git a/haddock-api/src/Haddock/Backends/Xhtml.hs b/haddock-api/src/Haddock/Backends/Xhtml.hs
index 3b085c8e..8e133e65 100644
--- a/haddock-api/src/Haddock/Backends/Xhtml.hs
+++ b/haddock-api/src/Haddock/Backends/Xhtml.hs
@@ -64,7 +64,7 @@ ppHtml :: String
        -> Maybe String                 -- ^ Package
        -> [Interface]
        -> FilePath                     -- ^ Destination directory
-       -> Maybe (Doc GHC.RdrName)      -- ^ Prologue text, maybe
+       -> Maybe (MDoc GHC.RdrName)     -- ^ Prologue text, maybe
        -> Themes                       -- ^ Themes
        -> SourceURLs                   -- ^ The source URL (--source)
        -> WikiURLs                     -- ^ The wiki URL (--wiki)
@@ -246,7 +246,7 @@ ppHtmlContents
    -> Maybe String
    -> SourceURLs
    -> WikiURLs
-   -> [InstalledInterface] -> Bool -> Maybe (Doc GHC.RdrName)
+   -> [InstalledInterface] -> Bool -> Maybe (MDoc GHC.RdrName)
    -> Bool
    -> Qualification  -- ^ How to qualify names
    -> IO ()
@@ -270,7 +270,7 @@ ppHtmlContents odir doctitle _maybe_package
   ppHtmlContentsFrame odir doctitle themes ifaces debug
 
 
-ppPrologue :: Qualification -> String -> Maybe (Doc GHC.RdrName) -> Html
+ppPrologue :: Qualification -> String -> Maybe (MDoc GHC.RdrName) -> Html
 ppPrologue _ _ Nothing = noHtml
 ppPrologue qual title (Just doc) =
   divDescription << (h1 << title +++ docElement thediv (rdrDocToHtml qual doc))
@@ -590,7 +590,7 @@ processForMiniSynopsis mdl unicode qual ExportDecl { expItemDecl = L _loc decl0
       map (ppNameMini Prefix mdl . nameOccName . getName . unLoc) lnames
     _ -> []
 processForMiniSynopsis _ _ qual (ExportGroup lvl _id txt) =
-  [groupTag lvl << docToHtml Nothing qual txt]
+  [groupTag lvl << docToHtml Nothing qual (mkMeta txt)]
 processForMiniSynopsis _ _ _ _ = []
 
 
@@ -625,7 +625,7 @@ ppModuleContents qual exports
     | otherwise = ( html:secs, rest2 )
     where
       html = linkedAnchor (groupId id0)
-             << docToHtmlNoAnchors (Just id0) qual doc +++ mk_subsections ssecs
+             << docToHtmlNoAnchors (Just id0) qual (mkMeta doc) +++ mk_subsections ssecs
       (ssecs, rest1) = process lev rest
       (secs,  rest2) = process n   rest1
   process n (_ : rest) = process n rest
@@ -649,7 +649,7 @@ processExport :: Bool -> LinksInfo -> Bool -> Qualification
               -> ExportItem DocName -> Maybe Html
 processExport _ _ _ _ ExportDecl { expItemDecl = L _ (InstD _) } = Nothing -- Hide empty instances
 processExport summary _ _ qual (ExportGroup lev id0 doc)
-  = nothingIf summary $ groupHeading lev id0 << docToHtml (Just id0) qual doc
+  = nothingIf summary $ groupHeading lev id0 << docToHtml (Just id0) qual (mkMeta doc)
 processExport summary links unicode qual (ExportDecl decl doc subdocs insts fixities splice)
   = processDecl summary $ ppDecl summary links decl doc insts fixities subdocs splice unicode qual
 processExport summary _ _ qual (ExportNoDecl y [])
diff --git a/haddock-api/src/Haddock/Backends/Xhtml/DocMarkup.hs b/haddock-api/src/Haddock/Backends/Xhtml/DocMarkup.hs
index 741e97e0..565adef2 100644
--- a/haddock-api/src/Haddock/Backends/Xhtml/DocMarkup.hs
+++ b/haddock-api/src/Haddock/Backends/Xhtml/DocMarkup.hs
@@ -21,11 +21,13 @@ module Haddock.Backends.Xhtml.DocMarkup (
 
 import Control.Applicative ((<$>))
 
+import Data.List
+import Data.Monoid (mconcat)
 import Haddock.Backends.Xhtml.Names
 import Haddock.Backends.Xhtml.Utils
 import Haddock.Types
 import Haddock.Utils
-import Haddock.Doc (combineDocumentation)
+import Haddock.Doc (combineDocumentation, emptyMetaDoc, metaDocAppend)
 
 import Text.XHtml hiding ( name, p, quote )
 import Data.Maybe (fromMaybe)
@@ -93,8 +95,8 @@ parHtmlMarkup qual insertAnchors ppId = Markup {
 -- from changing if it is possible to recover the layout information
 -- we won't need after the fact.
 data Hack a id =
-  UntouchedDoc (DocH a id)
-  | CollapsingHeader (Header (DocH a id)) (DocH a id) Int (Maybe String)
+  UntouchedDoc (MetaDoc a id)
+  | CollapsingHeader (Header (DocH a id)) (MetaDoc a id) Int (Maybe String)
   | HackAppend (Hack a id) (Hack a id)
   deriving Eq
 
@@ -110,15 +112,15 @@ toHack :: Int -- ^ Counter for header IDs which serves to assign
        -- this should work more or less fine: it is in fact the
        -- implicit assumption the collapse/expand mechanism makes for
        -- things like ‘Instances’ boxes.
-       -> [DocH a id] -> Hack a id
-toHack _ _ [] = UntouchedDoc DocEmpty
+       -> [MetaDoc a id] -> Hack a id
+toHack _ _ [] = UntouchedDoc emptyMetaDoc
 toHack _ _ [x] = UntouchedDoc x
-toHack n nm (DocHeader (Header l (DocBold x)):xs) =
+toHack n nm (MetaDoc { _doc = DocHeader (Header l (DocBold x)) }:xs) =
   let -- Header with dropped bold
       h = Header l x
       -- Predicate for takeWhile, grab everything including ‘smaller’
       -- headers
-      p (DocHeader (Header l' _)) = l' > l
+      p (MetaDoc { _doc = DocHeader (Header l' _) }) = l' > l
       p _ = True
       -- Stuff ‘under’ this header
       r = takeWhile p xs
@@ -128,16 +130,18 @@ toHack n nm (DocHeader (Header l (DocBold x)):xs) =
       app y ys = HackAppend y (toHack (n + 1) nm ys)
   in case r of
       -- No content under this header
-      [] -> CollapsingHeader h DocEmpty n nm `app` r'
+      [] -> CollapsingHeader h emptyMetaDoc n nm `app` r'
       -- We got something out, stitch it back together into one chunk
-      y:ys -> CollapsingHeader h (foldl DocAppend y ys) n nm `app` r'
+      y:ys -> CollapsingHeader h (foldl metaDocAppend y ys) n nm `app` r'
 toHack n nm (x:xs) = HackAppend (UntouchedDoc x) (toHack n nm xs)
 
 -- | Remove ‘top-level’ 'DocAppend's turning them into a flat list.
 -- This lends itself much better to processing things in order user
 -- might look at them, such as in 'toHack'.
-flatten :: DocH a id -> [DocH a id]
-flatten (DocAppend x y) = flatten x ++ flatten y
+flatten :: MetaDoc a id -> [MetaDoc a id]
+flatten MetaDoc { _meta = m, _doc = DocAppend x y } =
+  let f z = MetaDoc { _meta = m, _doc = z }
+  in flatten (f x) ++ flatten (f y)
 flatten x = [x]
 
 -- | Generate the markup needed for collapse to happen. For
@@ -146,24 +150,40 @@ flatten x = [x]
 -- 'CollapsingHeader', we attach extra info to the generated 'Html'
 -- that allows us to expand/collapse the content.
 hackMarkup :: DocMarkup id Html -> Hack (ModuleName, OccName) id -> Html
-hackMarkup fmt h = case h of
-  UntouchedDoc d -> markup fmt d
-  CollapsingHeader (Header lvl titl) par n nm ->
-    let id_ = makeAnchorId $ "ch:" ++ fromMaybe "noid:" nm ++ show n
-        col' = collapseControl id_ True "caption"
-        instTable = (thediv ! collapseSection id_ True [] <<)
-        lvs = zip [1 .. ] [h1, h2, h3, h4, h5, h6]
-        getHeader = fromMaybe caption (lookup lvl lvs)
-        subCation = getHeader ! col' << markup fmt titl
-    in (subCation +++) . instTable $ markup fmt par
-  HackAppend d d' -> markupAppend fmt (hackMarkup fmt d) (hackMarkup fmt d')
+hackMarkup fmt' h' =
+  let (html, ms) = hackMarkup' fmt' h'
+  in html +++ renderMeta fmt' (mconcat ms)
+  where
+    hackMarkup' :: DocMarkup id Html -> Hack (ModuleName, OccName) id
+                -> (Html, [Meta])
+    hackMarkup' fmt h = case h of
+      UntouchedDoc d -> (markup fmt $ _doc d, [_meta d])
+      CollapsingHeader (Header lvl titl) par n nm ->
+        let id_ = makeAnchorId $ "ch:" ++ fromMaybe "noid:" nm ++ show n
+            col' = collapseControl id_ True "caption"
+            instTable = (thediv ! collapseSection id_ True [] <<)
+            lvs = zip [1 .. ] [h1, h2, h3, h4, h5, h6]
+            getHeader = fromMaybe caption (lookup lvl lvs)
+            subCaption = getHeader ! col' << markup fmt titl
+        in ((subCaption +++) . instTable $ markup fmt (_doc par), [_meta par])
+      HackAppend d d' -> let (x, m) = hackMarkup' fmt d
+                             (y, m') = hackMarkup' fmt d'
+                         in (markupAppend fmt x y, m ++ m')
+
+renderMeta :: DocMarkup id Html -> Meta -> Html
+renderMeta fmt (Meta { _version = Just x }) =
+  markupParagraph fmt . markupEmphasis fmt . toHtml $
+    "Since: " ++ formatVersion x
+  where
+    formatVersion v = concat . intersperse "." $ map show v
+renderMeta _ _ = noHtml
 
 -- | Goes through 'hackMarkup' to generate the 'Html' rather than
 -- skipping straight to 'markup': this allows us to employ XHtml
--- specific hacks to the tree before first.
+-- specific hacks to the tree first.
 markupHacked :: DocMarkup id Html
              -> Maybe String
-             -> Doc id
+             -> MDoc id
              -> Html
 markupHacked fmt n = hackMarkup fmt . toHack 0 n . flatten
 
@@ -171,23 +191,23 @@ markupHacked fmt n = hackMarkup fmt . toHack 0 n . flatten
 -- ugly extra whitespace with some browsers).  FIXME: Does this still apply?
 docToHtml :: Maybe String -- ^ Name of the thing this doc is for. See
                           -- comments on 'toHack' for details.
-          -> Qualification -> Doc DocName -> Html
+          -> Qualification -> MDoc DocName -> Html
 docToHtml n qual = markupHacked fmt n . cleanup
   where fmt = parHtmlMarkup qual True (ppDocName qual Raw)
 
 -- | Same as 'docToHtml' but it doesn't insert the 'anchor' element
 -- in links. This is used to generate the Contents box elements.
 docToHtmlNoAnchors :: Maybe String -- ^ See 'toHack'
-                   -> Qualification -> Doc DocName -> Html
+                   -> Qualification -> MDoc DocName -> Html
 docToHtmlNoAnchors n qual = markupHacked fmt n . cleanup
   where fmt = parHtmlMarkup qual False (ppDocName qual Raw)
 
-origDocToHtml :: Qualification -> Doc Name -> Html
+origDocToHtml :: Qualification -> MDoc Name -> Html
 origDocToHtml qual = markupHacked fmt Nothing . cleanup
   where fmt = parHtmlMarkup qual True (const $ ppName Raw)
 
 
-rdrDocToHtml :: Qualification -> Doc RdrName -> Html
+rdrDocToHtml :: Qualification -> MDoc RdrName -> Html
 rdrDocToHtml qual = markupHacked fmt Nothing . cleanup
   where fmt = parHtmlMarkup qual True (const ppRdrName)
 
@@ -205,13 +225,13 @@ docSection n qual = maybe noHtml (docSection_ n qual) . combineDocumentation
 
 
 docSection_ :: Maybe Name -- ^ Name of the thing this doc is for
-            -> Qualification -> Doc DocName -> Html
+            -> Qualification -> MDoc DocName -> Html
 docSection_ n qual =
   (docElement thediv <<) . docToHtml (getOccString <$> n) qual
 
 
-cleanup :: Doc a -> Doc a
-cleanup = markup fmtUnParagraphLists
+cleanup :: MDoc a -> MDoc a
+cleanup = overDoc (markup fmtUnParagraphLists)
   where
     -- If there is a single paragraph, then surrounding it with <P>..</P>
     -- can add too much whitespace in some browsers (eg. IE).  However if
diff --git a/haddock-api/src/Haddock/Backends/Xhtml/Layout.hs b/haddock-api/src/Haddock/Backends/Xhtml/Layout.hs
index c5d8b7a3..e6a91391 100644
--- a/haddock-api/src/Haddock/Backends/Xhtml/Layout.hs
+++ b/haddock-api/src/Haddock/Backends/Xhtml/Layout.hs
@@ -115,7 +115,7 @@ divTopDecl :: Html -> Html
 divTopDecl = thediv ! [theclass "top"]
 
 
-type SubDecl = (Html, Maybe (Doc DocName), [Html])
+type SubDecl = (Html, Maybe (MDoc DocName), [Html])
 
 
 divSubDecls :: (HTML a) => String -> a -> Maybe Html -> Html