Move traceE to Control.Effect & generalize to Effectful contexts.

src/Control/Abstract/Evaluator.hs

@@ -2,8 +2,6 @@
 module Control.Abstract.Evaluator
   ( Evaluator(..)
   -- * Effects
-  , Trace(..)
-  , traceE
   , EvalClosure(..)
   , evaluateClosureBody
   , runEvalClosure
@@ -37,9 +35,8 @@ import Control.Monad.Effect.NonDet
 import Control.Monad.Effect.Reader hiding (runReader)
 import Control.Monad.Effect.Resumable
 import Control.Monad.Effect.State hiding (runState)
-import Control.Monad.Effect.Trace
 import Data.Abstract.Module
-import Prologue hiding (trace)
+import Prologue
 
 -- | An 'Evaluator' is a thin wrapper around 'Eff' with (phantom) type parameters for the location, term, and value types.
 --
@@ -54,12 +51,6 @@ deriving instance Member NonDet effects => Alternative (Evaluator location term
 
 -- Effects
 
--- | Trace into the current context.
--- TODO: Someday we can generalize this to work for Task and Graph.
-traceE :: Member Trace effects => String -> Evaluator location term value effects ()
-traceE = raise . trace
-
-
 -- | An effect to evaluate a closure’s body.
 data EvalClosure term value resume where
   EvalClosure :: term -> EvalClosure term value value

src/Control/Effect.hs

@@ -5,8 +5,10 @@ module Control.Effect
 , Eff.Reader
 , Eff.State
 , Fresh
+, Trace
 , send
 , throwResumable
+, traceE
 -- * Handlers
 , run
 , runM
@@ -28,7 +30,7 @@ import qualified Control.Monad.Effect.Reader as Eff
 import           Control.Monad.Effect.Resumable
 import qualified Control.Monad.Effect.State as Eff
 import           Control.Monad.Effect.Trace
-import           Prologue hiding (throwError)
+import           Prologue hiding (throwError, trace)
 
 -- | Types wrapping 'Eff.Eff' actions.
 --
@@ -52,6 +54,10 @@ send = raise . Eff.send
 throwResumable :: (Member (Resumable exc) effects, Effectful m) => exc v -> m effects v
 throwResumable = raise . throwError
 
+-- | Trace into the current context.
+traceE :: (Effectful m, Member Trace effects) => String -> m effects ()
+traceE = raise . trace
+
 
 -- Handlers