package ast

import "fmt"

type Visitor[T any] interface {
	VisitAtom(*Atom) T
	VisitAbstraction(*Abstraction) T
	VisitApplication(*Application) T
}

func Visit[T any](visitor Visitor[T], node Expression) T {
	switch node := node.(type) {
	case *Atom:
		return visitor.VisitAtom(node)
	case *Abstraction:
		return visitor.VisitAbstraction(node)
	case *Application:
		return visitor.VisitApplication(node)
	default:
		panic(fmt.Sprintf("unknown node %t", node))
	}
}