Classification and functions of golang function types

The function type in the Go language is the type of function pointer, which can be divided into the following categories: Func: the most common function type parameter type and return value type: specify the function parameters and return value type. Variable parameters: allow the function to accept any Number of parameters named return values: Allow functions to have multiple return values ​​with names

Golang function types and their uses

In Go language, function type is the type of function pointer. It allows functions to be passed as arguments to other functions or stored in variables. Function types in Go can be divided into the following categories based on their signatures:

Func

The most general function type with no explicit parameters or return value. Use func() to define.

Parameter type and Return value type

specifies the function parameter and return value type. For example, func(int) string indicates that a function accepts an int parameter and returns a string.

Types with variable parameters

Use ... to represent a variable number of parameters. For example, func(...int) indicates that a function accepts any number of int arguments.

With named return values

Using named return values ​​allows a function to have multiple return values, each with its own name. For example, func() (name string, age int) instructs a function to return a tuple with name and age.

Practical case: Comparing function types

The following program shows how to compare equality of different function types:

package main

import "fmt"

// 定义比较函数
func Compare(x, y int) int {
    return x - y
}

// 定义拥有命名返回值的比较函数
func CompareNamed(x, y int) (int, string) {
    if x == y {
        return 0, "Equal"
    } else if x < y {
        return -1, "Less"
    } else {
        return 1, "Greater"
    }
}

func main() {
    // 比较函数类型是否相等（类型安全）
    fmt.Println(Compare == CompareNamed) // false

    // 比较函数值是否相等（类型不安全）
    fmt.Println(Compare == CompareNamed(0, 0)) // true
}

In the output, we Seeing equality of function types is subject to type safety rules, whereas equality of function values ​​is not.

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