RST reader: better handling of indirect roles.

Previously the parser failed on this kind of case

    .. role:: indirect(code)

    .. role:: py(indirect)
       :language: python

    :py:`hi`

Now it currectly recognizes `:py:` as a code role.

The previous test for this didn't work, because the
name of the indirect role was the same as the language
defined its parent, os it didn't really test for this
behavior.  Updated test.

src/Text/Pandoc/Readers/RST.hs

@@ -614,20 +614,22 @@ directive' = do
             return mempty
 
 -- TODO:
---  - Silently ignores illegal fields
 --  - Only supports :format: fields with a single format for :raw: roles,
 --    change Text.Pandoc.Definition.Format to fix
 addNewRole :: String -> [(String, String)] -> RSTParser Blocks
 addNewRole roleString fields = do
     (role, parentRole) <- parseFromString inheritedRole roleString
     customRoles <- stateRstCustomRoles <$> getState
-    let (baseRole, baseFmt, baseAttr) =
-            maybe (parentRole, Nothing, nullAttr) id $
-              M.lookup parentRole customRoles
+    let getBaseRole (r, f, a) roles =
+            case M.lookup r roles of
+                 Just (r', f', a') -> getBaseRole (r', f', a') roles
+                 Nothing -> (r, f, a)
+        (baseRole, baseFmt, baseAttr) =
+               getBaseRole (parentRole, Nothing, nullAttr) customRoles
         fmt = if parentRole == "raw" then lookup "format" fields else baseFmt
         annotate :: [String] -> [String]
         annotate = maybe id (:) $
-            if parentRole == "code"
+            if baseRole == "code"
                then lookup "language" fields
                else Nothing
         attr = let (ident, classes, keyValues) = baseAttr
@@ -636,12 +638,12 @@ addNewRole roleString fields = do
 
     -- warn about syntax we ignore
     flip mapM_ fields $ \(key, _) -> case key of
-        "language" -> when (parentRole /= "code") $ addWarning Nothing $
+        "language" -> when (baseRole /= "code") $ addWarning Nothing $
             "ignoring :language: field because the parent of role :" ++
-            role ++ ": is :" ++ parentRole ++ ": not :code:"
-        "format" -> when (parentRole /= "raw") $ addWarning Nothing $
+            role ++ ": is :" ++ baseRole ++ ": not :code:"
+        "format" -> when (baseRole /= "raw") $ addWarning Nothing $
             "ignoring :format: field because the parent of role :" ++
-            role ++ ": is :" ++ parentRole ++ ": not :raw:"
+            role ++ ": is :" ++ baseRole ++ ": not :raw:"
         _ -> addWarning Nothing $ "ignoring unknown field :" ++ key ++
              ": in definition of role :" ++ role ++ ": in"
     when (parentRole == "raw" && countKeys "format" > 1) $

tests/rst-reader.native

@@ -325,7 +325,7 @@ Pandoc (Meta {unMeta = fromList [("author",MetaList [MetaInlines [Str "John",Spa
 ,Para [Str "And",Space,Str "some",Space,Str "inline",Space,Str "haskell",Space,Code ("",["haskell","sourceCode"],[]) "fmap id [1,2..10]",Str "."]
 ,Null
 ,Null
-,Para [Str "Indirect",Space,Str "python",Space,Str "role",Space,Code ("",["python","indirect","sourceCode"],[]) "[x*x for x in [1,2,3,4,5]]",Str "."]
+,Para [Str "Indirect",Space,Str "python",Space,Str "role",Space,Code ("",["py","python","indirect","sourceCode"],[]) "[x*x for x in [1,2,3,4,5]]",Str "."]
 ,Null
 ,Null
 ,Para [Str "Different",Space,Str "indirect",Space,Str "C",Space,Code ("",["c","different-indirect","sourceCode"],[]) "int x = 15;",Str "."]

tests/rst-reader.rst

@@ -611,10 +611,10 @@ And some inline haskell :haskell:`fmap id [1,2..10]`.
 
 .. role:: indirect(code)
 
-.. role:: python(indirect)
+.. role:: py(indirect)
    :language: python
 
-Indirect python role :python:`[x*x for x in [1,2,3,4,5]]`.
+Indirect python role :py:`[x*x for x in [1,2,3,4,5]]`.
 
 .. role:: different-indirect(code)
    :language: c