package builtins

import "git.sr.ht/~cco/go-scopes/forge"

type FE = forge.FE
type XT = forge.XT

type builtins struct {
	Add, Dup, Get, Lit, Mult, Put XT
}

func Get(f FE) *builtins {
	m := f.Voc().Lookup("builtins")
	if m.IsNothing() {
		b := setup(f)
		f.Voc().Register("builtins", b)
		return b
	}
	return m.Value().(*builtins)
}

func setup(f FE) *builtins {
	voc := f.Voc()
	r := func(name string, fct forge.Callable) XT {
		return forge.Register(voc, forge.GoFunc(name, fct))
	}
	return &builtins{
		Add:  r("+", func(f FE, _ XT) { f.Push(f.Pop().(int) + f.Pop().(int)) }),
		Dup:  r("dup", func(f FE, _ XT) { f.Push(f.Peek(0)) }),
		Get:  r("@", func(f FE, _ XT) { f.Push(f.Pop().(forge.FPtr).Value()) }),
		Lit:  r("literal", func(f FE, _ XT) { f.Literal() }),
		Mult: r("*", func(f FE, _ XT) { f.Push(f.Pop().(int) * f.Pop().(int)) }),
		Put:  r("!", func(f FE, _ XT) { f.Pop().(forge.FPtr).Set(f.Pop()) }),
	}
}