Tour of Go 2.0

Function values

In Go, functions are values. You can assign them to variables, pass them into other functions, and return them — just like any other type.

This makes patterns like callbacks and higher-order functions straightforward.

Try it: Pass math.Sqrt to compute and see what comes back.

main.go ▶ Run in Playground 
package main

import (
	"fmt"
	"math"
)

func compute(fn func(float64, float64) float64) float64 {
	return fn(3, 4)
}

func main() {
	hypot := func(x, y float64) float64 {
		return math.Sqrt(x*x + y*y)
	}
	fmt.Println(hypot(5, 12))

	fmt.Println(compute(hypot))
	fmt.Println(compute(math.Pow))
}