{-# OPTIONS_GHC -fglasgow-exts #-} module MO.Run ( module MO.Run, module MO.Base ) where -- FIXME: systematize a nice order for imports (steal Pugs') import MO.Util import MO.Base import MO.Compile as C import StringTable.AtomMap as M import Data.Typeable hiding (cast) import qualified Data.Typeable as Typeable import Data.Sequence (Seq) import qualified Data.Sequence as Seq -- Little overview. -- -- Suppose someone is calling a method, like: $foo.moose(1,2,3). Usually, we -- create a MethodInvocation containing "moose" as the name of the method and -- some Arguments thing, contaning the "1,2,3". -- -- The "$foo" object is _represented_ by an Invocant datatype, which has a -- pointer to "$foo" itself and an ResponderInterface (usually provided by the -- Class that $foo was instantiated), which knows how to answer for a method -- call, this is called 'dispatch' in the ResponderInterface class. -- -- One example of ResponderInterface is the MethodTable, it has a Map of -- MethodCompileds (identified by MethodName). Its 'dispatch' takes an Invocant -- and a MethodInvocation, add the Invocant to the MInv Arguments, -- lookup the MInv method name in it's on table, if found, run the compiled method -- with the augmented Arguments. -- -- The function ivDispatch does almost same as 'dispatch', but it gets the RI -- that the Invocant has inside it (given by the Class, for example). So you can -- think of "$foo.moose(1,2,3)" as a call to -- "ivDispatch (Invocant_of_$foo) (Arguments_containing_(1,2,3))" -- FIXME: At first we thought of having these two abstractions, but now -- seem unnecessary, but I may be forgetting something :P -- class Invocation a -- class Responder a data MethodInvocation m = MkMethodInvocation { mi_name :: !MethodName , mi_arguments :: !(Arguments m) } class Monad m => ResponderInterface m a | a -> m where fromMethodList :: [(MethodName, MethodCompiled m)] -> m a dispatch :: a -> Invocant m -> MethodInvocation m -> m (Invocant m) -- here for debugging purposes. -- toNameList :: a -> [MethodName] {- instance ResponderInterface m a => Show a where show = show . toNameList -} data Monad m => NoResponse m = NoResponse instance Monad m => ResponderInterface m (NoResponse m) where dispatch _ _ _ = fail "Dispatch failed - NO CARRIER" fromMethodList _ = return NoResponse -- toNameList _ = [] emptyResponder :: (Typeable1 m, Monad m) => AnyResponder m emptyResponder = MkResponder (return NoResponse) -- | This is a static method table. data MethodTable m = MkMethodTable { mt_methods :: !(M.AtomMap (MethodCompiled m)) } instance (Typeable1 m, Monad m) => ResponderInterface m (MethodTable m) where fromMethodList = return . MkMethodTable . M.fromList dispatch mt responder inv@(MkMethodInvocation n args) = case M.lookup n (mt_methods mt) of Just method_compiled -> do runMC method_compiled (withInvocant args responder) _ -> fail $ "Can't locate object method " ++ show n ++ " of invocant: " ++ show responder -- toNameList = M.keys . mt_methods data AnyResponder m = forall c. ResponderInterface m c => MkResponder !(m c) instance (Typeable1 m, Monad m) => Typeable (AnyResponder m) where typeOf _ = mkTyConApp (mkTyCon "AnyResponder") [typeOf1 (undefined :: m ())] -- Invocant represent an object aggregated with an ResponderInterface fromInvocant :: forall m b. (Typeable1 m, Monad m, Typeable b) => Arguments m -> m b fromInvocant CaptSub{} = fail "No invocant" fromInvocant CaptMeth{ c_invocant = MkInvocant x _ } = case Typeable.cast x of Just y -> return y _ -> fail $ "Could not coerce from " ++ (show $ typeOf x) ++ " to " ++ (show $ typeOf (undefined :: b)) instance (Typeable1 m, Monad m) => Typeable (Invocant m) where typeOf _ = mkTyConApp (mkTyCon "Invocant") [typeOf1 (undefined :: m ())] ivDispatch :: (Typeable1 m, Monad m) => Invocant m -> MethodInvocation m -> m (Invocant m) ivDispatch i@(MkInvocant _ (MkResponder ri)) mi = do table <- ri dispatch table i mi instance (Typeable1 m, Monad m) => Show (Invocant m) where show (MkInvocant x _) = show x instance (Typeable1 m, Monad m) => Eq (Invocant m) where MkInvocant a _ == MkInvocant b _ = a ?==? b instance (Typeable1 m, Monad m) => Ord (Invocant m) where MkInvocant a _ `compare` MkInvocant b _ = a ?<=>? b -- Helpers to create simple/empty invocants. __ :: (Typeable1 m, Monad m, Ord a, Show a, Typeable a) => a -> Invocant m __ = (`MkInvocant` emptyResponder) -- Helper to create a Arguments based on a list of Invocants mkArgs :: (Typeable1 m, Monad m) => [Invocant m] -> Arguments m mkArgs x = CaptSub{ c_feeds = Seq.singleton (MkFeed { f_positionals = Seq.fromList x, f_nameds = M.empty }) }