| // Copyright 2014 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 interfaces | |
| type I interface { | |
| Rand() int32 | |
| } | |
| func Add3(r I) int32 { | |
| return r.Rand() + r.Rand() + r.Rand() | |
| } | |
| // chosen by fair dice roll. | |
| // guaranteed to be random. | |
| type seven struct{} | |
| func (seven) Rand() int32 { return 7 } | |
| func Seven() I { return seven{} } |