function composer

compose_func.go

package main

import "fmt"

func makeAdder(x int) func(x int) int {
	return func(n int) int {
		return x + n
	}
}

func mul3(x int) int {
	return x * 3
}

func compose(f, g func(x int) int) func(x int) int {
	return func(n int) int {
		return f(g(n))
	}
}

func main() {
	fmt.Println(mul3(3))

	add1 := makeAdder(1)
	fmt.Println(add1(100))

	fg := compose(mul3, add1)
	fmt.Println(fg(10))
}