Method Select

query.go:1141–1180

(t iterator)

}

func (u *unionQuery) Select(t iterator) NodeNavigator {
	if u.iterator == nil {
		var list []NodeNavigator
		var m = make(map[uint64]bool)
		root := t.Current().Copy()
		for {
			node := u.Left.Select(t)
			if node == nil {
				break
			}
			code := getHashCode(node.Copy())
			if _, ok := m[code]; !ok {
				m[code] = true
				list = append(list, node.Copy())
			}
		}
		t.Current().MoveTo(root)
		for {
			node := u.Right.Select(t)
			if node == nil {
				break
			}
			code := getHashCode(node.Copy())
			if _, ok := m[code]; !ok {
				m[code] = true
				list = append(list, node.Copy())
			}
		}
		var i int
		u.iterator = func() NodeNavigator {
			if i >= len(list) {
				return nil
			}
			node := list[i]
			i++
			return node
		}
	}
	return u.iterator()
}

func (u *unionQuery) Evaluate(t iterator) interface{} {
	u.iterator = nil