BF in go

bg.go

package main

import (
	"fmt"
	"os"
)

func main() {
	if len(os.Args) < 1 {
		fmt.Fprintf(os.Stderr, "usage: bf <program>")
		os.Exit(1)
	}
	res := brainfuck(os.Args[1])
	fmt.Println(res)
}

const MaxMemory = 256

func brainfuck(program string) string {
	var out []byte
	var inst = []byte(program)
	var data = make([]byte, MaxMemory)
	var dx = 0
	for ix := 0; ix < len(inst); ix++ {
		d := 1
		switch {
		case inst[ix] == '[' && data[dx] == 0:
			for d > 0 {
				ix++
				switch inst[ix] {
				case '[':
					d++
				case ']':
					d--
				}
			}
		case inst[ix] == ']' && data[dx] != 0:
			for d > 0 {
				ix--
				switch inst[ix] {
				case '[':
					d--
				case ']':
					d++
				}
			}
		case inst[ix] == '+':
			data[dx]++
		case inst[ix] == '-':
			data[dx]--
		case inst[ix] == '>':
			dx++
		case inst[ix] == '<':
			if dx > 0 {
				dx--
			}
		case inst[ix] == '.':
			out = append(out, data[dx])
		case inst[ix] == ',':
			fmt.Scanf("%c", &data[dx])
		default:
		}
	}

	return string(out)
}