How to use Function Pointers as Receivers

In Go, you can define methods on user-defined types (structs) that take receiver arguments as function pointers. This allows you to attach behavior to your custom types by defining functions that operate on them.

Golang Code

Here’s how you can use function pointers as receivers in Go:

package main

import (
	"fmt"
)

type Calculator struct {
	addFunc    func(int, int) int
	subtractFunc func(int, int) int
}

// Define methods using function pointer receivers
func (c *Calculator) SetAddFunc(adder func(int, int) int) {
	c.addFunc = adder
}

func (c *Calculator) SetSubtractFunc(subtractor func(int, int) int) {
	c.subtractFunc = subtractor
}

func main() {
	calc := &Calculator{}

	// Set function pointers for addition and subtraction
	calc.SetAddFunc(func(a, b int) int {
		return a + b
	})

	calc.SetSubtractFunc(func(a, b int) int {
		return a - b
	})

	// Use the function pointers to perform operations
	result1 := calc.addFunc(10, 5)
	result2 := calc.subtractFunc(10, 5)

	fmt.Printf("Addition: %d\n", result1)
	fmt.Printf("Subtraction: %d\n", result2)
}

Breaking Down the Code

In this example, we have a Calculator type with two fields that are function pointers: addFunc and subtractFunc. We define methods SetAddFunc and SetSubtractFunc that allow you to set these function pointers to custom functions.

In the main function, we create an instance of the Calculator and set the addFunc and subtractFunc using anonymous functions. Then, we use these function pointers to perform addition and subtraction operations.