{-# LANGUAGE FlexibleInstances #-} {-# LANGUAGE GADTs #-} {-# LANGUAGE GeneralizedNewtypeDeriving #-} {-# LANGUAGE LambdaCase #-} {-# LANGUAGE MultiParamTypeClasses #-} {-# LANGUAGE TypeOperators #-} {-# LANGUAGE UndecidableInstances #-} -- | A carrier for the 'Control.Effect.Trace' effect that ignores all traced results. Useful when you wish to disable tracing without removing all trace statements. -- -- @since 1.0.0.0 module Control.Carrier.Trace.Ignoring ( -- * Trace carrier runTrace , TraceC(..) -- * Trace effect , module Control.Effect.Trace ) where import Control.Algebra import Control.Applicative (Alternative) import Control.Effect.Trace import Control.Monad (MonadPlus) import Control.Monad.Fail as Fail import Control.Monad.Fix import Control.Monad.IO.Class import Control.Monad.Trans.Class -- | Run a 'Trace' effect, ignoring all traces. -- -- @ -- 'runTrace' ('trace' s) = 'pure' () -- @ -- @ -- 'runTrace' ('pure' a) = 'pure' a -- @ -- -- @since 1.0.0.0 runTrace :: TraceC m a -> m a runTrace (TraceC m) = m {-# INLINE runTrace #-} -- | @since 1.0.0.0 newtype TraceC m a = TraceC (m a) deriving (Alternative, Applicative, Functor, Monad, Fail.MonadFail, MonadFix, MonadIO, MonadPlus) instance MonadTrans TraceC where lift = TraceC {-# INLINE lift #-} instance Algebra sig m => Algebra (Trace :+: sig) (TraceC m) where alg hdl = \case L (Trace _) -> pure R other -> TraceC . alg (runTrace . hdl) other {-# INLINE alg #-}