Compact singature

Main.purs

module Main where

import Prelude

import Data.Foldable (fold)
import Data.Tuple.Nested (type (/\))
import Type.Prelude (Proxy(..))
import Effect (Effect)
import TryPureScript (h1, h2, p, text, list, indent, link, render, code)

class Compact a b c | a b -> c -- , c -> a b

instance Compact a a a
else instance Compact a b (a /\ b)


summary :: forall a b c. Compact a b c => Proxy a -> Proxy b -> Proxy c
summary _ _ = Proxy

x = summary (Proxy :: Proxy String) (Proxy :: Proxy String)

y = summary (Proxy :: Proxy String) (Proxy :: Proxy Int)