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🔥 cata.

This commit is contained in:
Rob Rix 2019-07-18 14:34:16 -04:00
parent 07616d5be9
commit 4cbc23b76d
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@ -3,15 +3,12 @@ module Data.Term
( Term(..)
, Syntax(..)
, iter
, cata
, interpret
) where
import Control.Effect.Carrier
import Control.Monad (ap)
import Control.Monad.Module
import Data.Coerce (coerce)
import Data.Functor.Const
import Data.Scope
data Term sig a
@ -79,15 +76,6 @@ iter var alg bound = go
Var a -> var (free a)
Term t -> alg (foldSyntax go bound free t)
cata :: Syntax sig
=> (a -> b)
-> (forall a . sig (Const b) a -> b)
-> (Incr () b -> a)
-> (x -> a)
-> Term sig x
-> b
cata var alg k h = getConst . iter (coerce var) (Const . alg) (coerce k) (Const . h)
interpret :: (Carrier sig m, Member eff sig, Syntax eff) => (forall a . Incr () (m a) -> m (Incr () (m a))) -> (a -> m b) -> Term eff a -> m b
interpret = iter id send