hmap.go

type Hmap[K any, V any, H helper[K]] struct {
	help H
	// ...
}

type helper[K any] interface {
	Hash(k K) uint64
	Equal(x, y K) bool
}

// Meth is a helper that calls Hash and Equal methods on the key
type Meth[K Key] struct{} // zero size

type Key interface {
	Hash() uint64
	Equal(any) bool
}

func (m Meth[K]) Hash(k K) uint64 {
	return k.Hash()
}
func (m Meth[K]) Equal(x, y K) bool {
	return x.Equal(y)
}

type HmapMeth[K Key, V any] Hmap[K, V, Meth[K]]

// Funcs is a helper that is configured with hash and equals functions.
// This allows using closures which allows context.
type Funcs[K any] struct {
	hfn  func(k K) uint64
	eqfn func(x, y K) bool
}

func (m Funcs[K]) Hash(k K) uint64 {
	return m.hfn(k)
}
func (m Funcs[K]) Equal(x, y K) bool {
	return m.eqfn(x, y)
}

type HmapFuncs[K any, V any] Hmap[K, V, Funcs[K]]

func NewHmapFuncs[K any, V any](hfn func(k K) uint64,
	eqfn func(x, y K) bool) *HmapFuncs[K, V] {
	return &HmapFuncs[K, V]{help: Funcs[K]{hfn: hfn, eqfn: eqfn}}
}