Function Fold

iterator.go:333–339

Fold reduces Iterator using function fn.

(it Iterator[T], init B, fn func(B, T) B)

// Fold reduces Iterator using function fn.
func Fold[T any, B any](it Iterator[T], init B, fn func(B, T) B) B {
	ret := init
	ForEach(it, func(v T) {
		ret = fn(ret, v)
	})
	return ret
}

type fuseIter[T any] struct {
	inner Iterator[T]