Qual.kt

package ekko.tree

/**
 * Types can be quantified by adding a list of predicates [predicates], to restrict
 * the ways in which type variables is instantiated.
 *
 * Example of `Num a => a`(in haskell):
 * ```kt
 * val predicates = listOf(IsIn(TVar(Ident("a", KStar), Ident("Num"))))
 *
 * Qual(predicates, TVar(Ident("a", KStar)))
 * ```
 */
data class Qual<A>(val predicates: Set<Pred>, val value: A)

sealed interface Pred

data class IsIn(val typ: Typ, val id: Ident) : Pred