V语言学习笔记-14泛型

目前的泛型主要有这三种：泛型结构体,泛型函数,泛型方法

泛型结构体

struct DB {
    driver string
}

struct User {
    db DB
mut:
    name string
}

struct Repo<T> {
    db DB
mut:
    model  T
}

fn new_repo<U>(db DB) Repo<U> {
    return Repo<U>{db: db}
}

fn test_generic_struct() {
    mut a :=  new_repo<User>(DB{})
    a.model.name = 'joe'
    mut b := Repo<User>{db: DB{}}
    b.model.name = 'joe'
    assert a.model.name == 'joe'
    assert b.model.name == 'joe'
}

泛型函数

判断2个数组是否相等的泛型函数

//vlib/builtin/array.v
fn array_eq<T>(a1, a2 []T) bool {
   if a1.len != a2.len {
      return false
   }
   for i := 0; i < a1.len; i++ {
      if a1[i] != a2[i] {
         return false
      }
   }
   return true
}

泛型方法

struct Point {
mut:
    x f64
    y f64
}

fn (mut p Point) translate<T>(x, y T) {
    p.x += x
    p.y += y
}

fn test_generic_method() {
    mut p := Point{}
    p.translate(2, 1.0)
    assert p.x == 2.0 && p.y == 1.0
}