// 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. // Interface values containing structures. package main import "os" var fail int func check(b bool, msg string) { if (!b) { println("failure in", msg) fail++ } } type I1 interface { Get() int; Put(int) } type S1 struct { i int } func (p S1) Get() int { return p.i } func (p S1) Put(i int) { p.i = i } func f1() { s := S1{1} var i I1 = s i.Put(2) check(i.Get() == 1, "f1 i") check(s.i == 1, "f1 s") } func f2() { s := S1{1} var i I1 = &s i.Put(2) check(i.Get() == 1, "f2 i") check(s.i == 1, "f2 s") } func f3() { s := &S1{1} var i I1 = s i.Put(2) check(i.Get() == 1, "f3 i") check(s.i == 1, "f3 s") } type S2 struct { i int } func (p *S2) Get() int { return p.i } func (p *S2) Put(i int) { p.i = i } // Disallowed by restriction of values going to pointer receivers // func f4() { // s := S2{1} // var i I1 = s // i.Put(2) // check(i.Get() == 2, "f4 i") // check(s.i == 1, "f4 s") // } func f5() { s := S2{1} var i I1 = &s i.Put(2) check(i.Get() == 2, "f5 i") check(s.i == 2, "f5 s") } func f6() { s := &S2{1} var i I1 = s i.Put(2) check(i.Get() == 2, "f6 i") check(s.i == 2, "f6 s") } type I2 interface { Get() int64; Put(int64) } type S3 struct { i, j, k, l int64 } func (p S3) Get() int64 { return p.l } func (p S3) Put(i int64) { p.l = i } func f7() { s := S3{1, 2, 3, 4} var i I2 = s i.Put(5) check(i.Get() == 4, "f7 i") check(s.l == 4, "f7 s") } func f8() { s := S3{1, 2, 3, 4} var i I2 = &s i.Put(5) check(i.Get() == 4, "f8 i") check(s.l == 4, "f8 s") } func f9() { s := &S3{1, 2, 3, 4} var i I2 = s i.Put(5) check(i.Get() == 4, "f9 i") check(s.l == 4, "f9 s") } type S4 struct { i, j, k, l int64 } func (p *S4) Get() int64 { return p.l } func (p *S4) Put(i int64) { p.l = i } // Disallowed by restriction of values going to pointer receivers // func f10() { // s := S4{1, 2, 3, 4} // var i I2 = s // i.Put(5) // check(i.Get() == 5, "f10 i") // check(s.l == 4, "f10 s") // } func f11() { s := S4{1, 2, 3, 4} var i I2 = &s i.Put(5) check(i.Get() == 5, "f11 i") check(s.l == 5, "f11 s") } func f12() { s := &S4{1, 2, 3, 4} var i I2 = s i.Put(5) check(i.Get() == 5, "f12 i") check(s.l == 5, "f12 s") } func main() { f1() f2() f3() // f4() f5() f6() f7() f8() f9() // f10() f11() f12() if fail > 0 { os.Exit(1) } }