Go语言中关于set的实现思考分析

type StrSet struct{
    data map[string]struct{}
}

type Set struct {
	data map[interface{}]struct{}
}

// New creates a new Set
func New(v ...interface{}) *Set {
	s := &Set{data: map[interface{}]struct{}{}}
	for _, ele := range v {
		s.data[ele] = struct{}{}
	}
	return s
}

// ...

// ToList returns data slice
func (s *Set) ToList() []interface{} {
	var data = make([]interface{}, len(s.data))
	var i int
	for d := range s.data {
		data[i] = d
		i++
	}
	return data
}

func main() {
	var l1 = []int{1, 2, 3}
	var l2 = []int{4, 5, 6}
	var s = NewSet(l1, l2)
	for _, e := range s.ToList() {
		fmt.Println(e)
	}
}

func main() {
	var s = NewSet("a", "b", "c")
	var tmp []string
	for _, e := range s.ToList() {
		tmp = append(tmp, e.(string))
	}
	test(tmp)
}

type Set[T comparable] struct {
	data map[T]struct{}
}

// New creates a new Set
func NewSet[T comparable](v ...T) *Set[T] {
	s := &Set[T]{data: map[T]struct{}{}}
	for _, ele := range v {
		s.data[ele] = struct{}{}
	}
	return s
}

func (s *Set[T]) Add(v ...T) {
	for _, ele := range v {
		s.data[ele] = struct{}{}
	}
}

// ...

// ToList returns data slice
func (s *Set[T]) ToList() []T {
	var data = make([]T, len(s.data))
	var i int
	for d := range s.data {
		data[i] = d
		i++
	}
	return data
}

func test1(data []string) {
	// ...
}

func test2(data []float64) {
	// ...
}

func main() {
	var s1 = NewSet("a", "b", "c")
	test1(s1.ToList())

	var s2 = NewSet(1.3, 2.2, 3)
	test2(s2.ToList())
}

type IntSet = Set[int]

func NewIntSet(v ...int) *IntSet {
	return NewSet[int](v...)
}

func main() {
	var s = NewIntSet(1, 2, 3)
	test3(s.ToList())

	// 编译错误
	// s.Add("a", "b", "c")
}

type setNode[T comparable] struct {
	val  T
	pre  *setNode[T]
	next *setNode[T]
}

type FifoSet[T comparable] struct {
	head *setNode[T]
	tail *setNode[T]
	data map[T]*setNode[T]
}

// add data, make it first in first out
func (l *FifoSet[T]) Add(v ...T) {
	if len(v) == 0 {
		return
	}

	var i int
	if l.head == nil {
		// first node
		n := &setNode[T]{
			val: v[i],
		}
		l.head = n
		l.tail = n
		l.data[v[i]] = n
		i++
	}
	for ; i < len(v); i++ {
		if _, ok := l.data[v[i]]; !ok {
            // when missing, insert
			n := &setNode[T]{
				val:  v[i],
				pre:  l.tail,
				next: nil,
			}
			l.tail.next = n
			l.tail = n
			l.data[v[i]] = n
		}
	}
}

func main() {
	var s = NewFifoSet[string]()
	s.Add("e", "a", "b", "a", "c", "b")
	// e
	// a
    // b
	// c
	for _, v := range s.ToList() {
		fmt.Println(v)
	}
}