68 lines
2.2 KiB
Haskell
68 lines
2.2 KiB
Haskell
-- ghc-mod: Making Haskell development *more* fun
|
|
-- Copyright (C) 2015,2016 Daniel Gröber <dxld ÄT darkboxed DOT org>
|
|
--
|
|
-- This program is free software: you can redistribute it and/or modify
|
|
-- it under the terms of the GNU Affero General Public License as published by
|
|
-- the Free Software Foundation, either version 3 of the License, or
|
|
-- (at your option) any later version.
|
|
--
|
|
-- This program is distributed in the hope that it will be useful,
|
|
-- but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
-- GNU Affero General Public License for more details.
|
|
--
|
|
-- You should have received a copy of the GNU Affero General Public License
|
|
-- along with this program. If not, see <http://www.gnu.org/licenses/>.
|
|
|
|
{-# LANGUAGE GeneralizedNewtypeDeriving, StandaloneDeriving #-}
|
|
{-# LANGUAGE FlexibleInstances, UndecidableInstances #-}
|
|
|
|
module Language.Haskell.GhcMod.Monad.State where
|
|
|
|
import Language.Haskell.GhcMod.Types
|
|
import Language.Haskell.GhcMod.Monad.Newtypes
|
|
|
|
import Control.Monad
|
|
import Control.Monad.State.Strict (StateT(..))
|
|
import Control.Monad.Trans.Maybe (MaybeT(..))
|
|
import Control.Monad.State.Class (MonadState(..))
|
|
import Control.Monad.Trans.Class (MonadTrans(..))
|
|
import Prelude
|
|
|
|
class Monad m => GmState m where
|
|
gmsGet :: m GhcModState
|
|
gmsGet = gmsState (\s -> (s, s))
|
|
|
|
gmsPut :: GhcModState -> m ()
|
|
gmsPut s = gmsState (\_ -> ((), s))
|
|
|
|
gmsState :: (GhcModState -> (a, GhcModState)) -> m a
|
|
gmsState f = do
|
|
s <- gmsGet
|
|
let ~(a, s') = f s
|
|
gmsPut s'
|
|
return a
|
|
{-# MINIMAL gmsState | gmsGet, gmsPut #-}
|
|
|
|
instance GmState m => GmState (StateT s m) where
|
|
gmsGet = lift gmsGet
|
|
gmsPut = lift . gmsPut
|
|
gmsState = lift . gmsState
|
|
|
|
instance Monad m => GmState (StateT GhcModState m) where
|
|
gmsGet = get
|
|
gmsPut = put
|
|
gmsState = state
|
|
|
|
instance Monad m => GmState (GmT m) where
|
|
gmsGet = GmT get
|
|
gmsPut = GmT . put
|
|
gmsState = GmT . state
|
|
|
|
instance GmState m => GmState (MaybeT m) where
|
|
gmsGet = MaybeT $ Just `liftM` gmsGet
|
|
gmsPut = MaybeT . (Just `liftM`) . gmsPut
|
|
gmsState = MaybeT . (Just `liftM`) . gmsState
|
|
|
|
deriving instance (Monad m, GmState (GhcModT m)) => GmState (GmlT m)
|