1// run
2
3// Copyright 2009 The Go Authors. All rights reserved.
4// Use of this source code is governed by a BSD-style
5// license that can be found in the LICENSE file.
6
7// Test simultaneous assignment.
8
9package main
10
11var a, b, c, d, e, f, g, h, i int
12
13func printit() {
14	println(a, b, c, d, e, f, g, h, i)
15}
16
17func testit(permuteok bool) bool {
18	if a+b+c+d+e+f+g+h+i != 45 {
19		print("sum does not add to 45\n")
20		printit()
21		return false
22	}
23	return permuteok ||
24		a == 1 &&
25			b == 2 &&
26			c == 3 &&
27			d == 4 &&
28			e == 5 &&
29			f == 6 &&
30			g == 7 &&
31			h == 8 &&
32			i == 9
33}
34
35func swap(x, y int) (u, v int) {
36	return y, x
37}
38
39func main() {
40	a = 1
41	b = 2
42	c = 3
43	d = 4
44	e = 5
45	f = 6
46	g = 7
47	h = 8
48	i = 9
49
50	if !testit(false) {
51		panic("init val\n")
52	}
53
54	for z := 0; z < 100; z++ {
55		a, b, c, d, e, f, g, h, i = b, c, d, a, i, e, f, g, h
56
57		if !testit(z%20 != 19) {
58			print("on ", z, "th iteration\n")
59			printit()
60			panic("fail")
61		}
62	}
63
64	if !testit(false) {
65		print("final val\n")
66		printit()
67		panic("fail")
68	}
69
70	a, b = swap(1, 2)
71	if a != 2 || b != 1 {
72		panic("bad swap")
73	}
74
75	a, b = swap(swap(a, b))
76	if a != 2 || b != 1 {
77		panic("bad swap")
78	}
79}
80