// $G $D/$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 import "fmt" const ( a = iota; b; c; d; e; ) var x = []int{1,2,3} func f(x int, len *byte) { *len = byte(x); } func whatis(x interface{}) string { switch xx := x.(type) { default: return fmt.Sprint("default ", xx); case int, int8, int16, int32: return fmt.Sprint("signed ", xx); case int64: return fmt.Sprint("signed64 ", int64(xx)); case uint, uint8, uint16, uint32: return fmt.Sprint("unsigned ", xx); case uint64: return fmt.Sprint("unsigned64 ", uint64(xx)); case nil: return fmt.Sprint("nil ", xx); } panic("not reached"); } func whatis1(x interface{}) string { xx := x; switch xx.(type) { default: return fmt.Sprint("default ", xx); case int, int8, int16, int32: return fmt.Sprint("signed ", xx); case int64: return fmt.Sprint("signed64 ", xx.(int64)); case uint, uint8, uint16, uint32: return fmt.Sprint("unsigned ", xx); case uint64: return fmt.Sprint("unsigned64 ", xx.(uint64)); case nil: return fmt.Sprint("nil ", xx); } panic("not reached"); } func check(x interface{}, s string) { w := whatis(x); if w != s { fmt.Println("whatis", x, "=>", w, "!=", s); panic(); } w = whatis1(x); if w != s { fmt.Println("whatis1", x, "=>", w, "!=", s); panic(); } } func main() { check(1, "signed 1"); check(uint(1), "unsigned 1"); check(int64(1), "signed64 1"); check(uint64(1), "unsigned64 1"); check(1.5, "default 1.5"); check(nil, "nil "); }