A RPN calculator: Haskell vs. Go

rpn.go

package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
	"strings"
)

func solveRPN(line string) int {
	stack := []int{}
	input := strings.Split(line[:len(line)-1], " ")

	for _, v := range input {
		if v == "*" {
			stack = append(stack[:len(stack)-2], stack[len(stack)-2]*stack[len(stack)-1])
		} else if v == "+" {
			stack = append(stack[:len(stack)-2], stack[len(stack)-2]+stack[len(stack)-1])
		} else if v == "-" {
			stack = append(stack[:len(stack)-2], stack[len(stack)-2]-stack[len(stack)-1])
		} else {
			value, _ := strconv.Atoi(v)
			stack = append(stack, value)
		}
	}

	return stack[len(stack)-1]
}

func main() {
	fmt.Println("Your calculation: ")
	reader := bufio.NewReader(os.Stdin)
	line, _ := reader.ReadString('\n')
	fmt.Println(solveRPN(line))
}

rpn.hs

import Data.List

main = do
  putStrLn "Your calculation: "
  exp <- getLine
  print $ solveRPN exp

solveRPN :: (Num a, Read a) => String -> a
solveRPN = head . foldl foldingFunction [] . words
  where foldingFunction (x:y:ys) "*" = (x * y):ys
        foldingFunction (x:y:ys) "+" = (x + y):ys
        foldingFunction (x:y:ys) "-" = (y - x):ys
        foldingFunction xs numberString = read numberString:xs