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// run
// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Test simulating a Turing machine, sort of.
package main
// brainfuck
var p, pc int
var a [30000]byte
const prog = "++++++++++[>+++++++>++++++++++>+++>+<<<<-]>++.>+.+++++++..+++.>++.<<+++++++++++++++.>.+++.------.--------.>+.>.!"
func scan(dir int) {
for nest := dir; dir*nest > 0; pc += dir {
switch prog[pc+dir] {
case ']':
nest--
case '[':
nest++
}
}
}
func main() {
r := ""
for {
switch prog[pc] {
case '>':
p++
case '<':
p--
case '+':
a[p]++
case '-':
a[p]--
case '.':
r += string(a[p])
case '[':
if a[p] == 0 {
scan(1)
}
case ']':
if a[p] != 0 {
scan(-1)
}
default:
if r != "Hello World!\n" {
panic(r)
}
return
}
pc++
}
}
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