go/test/iota.go

// $G $F.go && $L $F.$A && ./$A.out

// 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.

package main

func assert(cond bool, msg string) {
	if !cond {
		print("assertion fail: ", msg, "\n")
		panic(1)
	}
}

const (
	x int = iota
	y = iota
	z = 1 << iota
	f float = 2 * iota
	g float = 4.5 * float(iota)
)

const (
	X = 0
	Y
	Z
)

const (
	A = 1 << iota
	B
	C
	D
	E = iota * iota
	F
	G
)

const (
	a = 1
	b = iota << a
	c = iota << b
	d
)

const (
	i = (a << iota) + (b * iota)
	j
	k
	l
)

const (
	m = iota == 0
	n
)

const (
	p = float(iota)
	q
	r
)

const (
	s = string(iota + 'a')
	t
)

const (
	abit, amask = 1 << iota, 1 << iota - 1
	bbit, bmask = 1 << iota, 1 << iota - 1
	cbit, cmask = 1 << iota, 1 << iota - 1
)

func main() {
	assert(x == 0, "x")
	assert(y == 1, "y")
	assert(z == 4, "z")
	assert(f == 6.0, "f")
	assert(g == 18.0, "g")

	assert(X == 0, "X")
	assert(Y == 0, "Y")
	assert(Z == 0, "Z")

	assert(A == 1, "A")
	assert(B == 2, "B")
	assert(C == 4, "C")
	assert(D == 8, "D")
	assert(E == 16, "E")
	assert(F == 25, "F")

	assert(a == 1, "a")
	assert(b == 2, "b")
	assert(c == 8, "c")
	assert(d == 12, "d")

	assert(i == 1, "i")
	assert(j == 4, "j")
	assert(k == 8, "k")
	assert(l == 14, "l")

	assert(m, "m")
	assert(!n, "n")

	assert(p == 0.0, "p")
	assert(q == 1.0, "q")
	assert(r == 2.0, "r")

	assert(s == "a", "s")
	assert(t == "b", "t")

	assert(abit == 1, "abit")
	assert(amask == 0, "amask")
	assert(bbit == 2, "bbit")
	assert(bmask == 1, "bmask")
	assert(cbit == 4, "cbit")
	assert(cmask == 3, "cmask")
}