| // 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 behavior of the blank identifier (_). |
| |
| package main |
| |
| import _ "fmt" |
| |
| var call string |
| |
| type T struct { |
| _, _, _ int |
| } |
| |
| func (T) _() { |
| } |
| |
| func (T) _() { |
| } |
| |
| const ( |
| c0 = iota |
| _ |
| _ |
| _ |
| c4 |
| ) |
| |
| var ints = []string{ |
| "1", |
| "2", |
| "3", |
| } |
| |
| func f() (int, int) { |
| call += "f" |
| return 1, 2 |
| } |
| |
| func g() (float64, float64) { |
| call += "g" |
| return 3, 4 |
| } |
| |
| func h(_ int, _ float64) { |
| } |
| |
| func i() int { |
| call += "i" |
| return 23 |
| } |
| |
| var _ = i() |
| |
| func main() { |
| if call != "i" { |
| panic("init did not run") |
| } |
| call = "" |
| _, _ = f() |
| a, _ := f() |
| if a != 1 { |
| panic(a) |
| } |
| b, _ := g() |
| if b != 3 { |
| panic(b) |
| } |
| _, a = f() |
| if a != 2 { |
| panic(a) |
| } |
| _, b = g() |
| if b != 4 { |
| panic(b) |
| } |
| _ = i() |
| if call != "ffgfgi" { |
| panic(call) |
| } |
| if c4 != 4 { |
| panic(c4) |
| } |
| |
| out := "" |
| for _, s := range ints { |
| out += s |
| } |
| if out != "123" { |
| panic(out) |
| } |
| |
| sum := 0 |
| for s := range ints { |
| sum += s |
| } |
| if sum != 3 { |
| panic(sum) |
| } |
| |
| h(a, b) |
| |
| m() |
| } |
| |
| type I interface { |
| M(_ int, y int) |
| } |
| |
| type TI struct{} |
| |
| func (TI) M(x int, y int) { |
| if x != y { |
| println("invalid M call:", x, y) |
| panic("bad M") |
| } |
| } |
| |
| var fp = func(_ int, y int) {} |
| |
| func init() { |
| fp = fp1 |
| } |
| |
| func fp1(x, y int) { |
| if x != y { |
| println("invalid fp1 call:", x, y) |
| panic("bad fp1") |
| } |
| } |
| |
| |
| func m() { |
| var i I |
| |
| i = TI{} |
| i.M(1, 1) |
| i.M(2, 2) |
| |
| fp(1, 1) |
| fp(2, 2) |
| } |
| |
| // useless but legal |
| var _ int = 1 |
| var _ = 2 |
| var _, _ = 3, 4 |
| |
| const _ = 3 |
| const _, _ = 4, 5 |
| |
| type _ int |
| |
| func _() { |
| panic("oops") |
| } |
| |
| func ff() { |
| var _ int = 1 |
| } |
| |