Basic currying in Go

curry.go

// Go Playground: https://play.golang.org/p/6C9Wj8uqmc
package main

import "fmt"

func increment(x int) int {
  return x + 1
}

func decrement(x int) int {
  return x - 1
}

func handler(s string) func(int) int {
  return func(x int) int {
    if s == "success" {
      return increment(x)
    }
    return decrement(x)
  }
}

func done(s string, x int) int {
  return handler(s)(x)
}

func main() {
  var x int
  x = done("success", x)
  fmt.Printf("Expected 1, got %v\n", x)
  
  x = done("failure", x)
  fmt.Printf("Expected 0, got %v\n", x)
  
  x = done("success", x)
  fmt.Printf("Expected 1, got %v\n", x)
  
  x = done("success", x)
  fmt.Printf("Expected 2, got %v\n", x)
}