blob: 879cfb98304b31caa1241a13a64e6c138e1188de [file] [log] [blame]
Russ Cox5d16d232009-09-09 00:18:16 -07001// $G $D/$F.go && $L $F.$A && ./$A.out
2
3// Copyright 2009 The Go Authors. All rights reserved.
4// Use of this source code is governed by a BSD-style
5// license that can be found in the LICENSE file.
6
7package main
8
9import "fmt"
10
11const (
12 a = iota;
13 b;
14 c;
15 d;
16 e;
17)
18
19var x = []int{1,2,3}
20
21func f(x int, len *byte) {
22 *len = byte(x);
23}
24
25func whatis(x interface{}) string {
26 switch xx := x.(type) {
27 default:
28 return fmt.Sprint("default ", xx);
29 case int, int8, int16, int32:
30 return fmt.Sprint("signed ", xx);
31 case int64:
32 return fmt.Sprint("signed64 ", int64(xx));
33 case uint, uint8, uint16, uint32:
34 return fmt.Sprint("unsigned ", xx);
35 case uint64:
36 return fmt.Sprint("unsigned64 ", uint64(xx));
37 case nil:
38 return fmt.Sprint("nil ", xx);
39 }
40 panic("not reached");
41}
42
43func whatis1(x interface{}) string {
44 xx := x;
45 switch xx.(type) {
46 default:
47 return fmt.Sprint("default ", xx);
48 case int, int8, int16, int32:
49 return fmt.Sprint("signed ", xx);
50 case int64:
51 return fmt.Sprint("signed64 ", xx.(int64));
52 case uint, uint8, uint16, uint32:
53 return fmt.Sprint("unsigned ", xx);
54 case uint64:
55 return fmt.Sprint("unsigned64 ", xx.(uint64));
56 case nil:
57 return fmt.Sprint("nil ", xx);
58 }
59 panic("not reached");
60}
61
62func check(x interface{}, s string) {
63 w := whatis(x);
64 if w != s {
65 fmt.Println("whatis", x, "=>", w, "!=", s);
66 panic();
67 }
68
69 w = whatis1(x);
70 if w != s {
71 fmt.Println("whatis1", x, "=>", w, "!=", s);
72 panic();
73 }
74}
75
76func main() {
77 check(1, "signed 1");
78 check(uint(1), "unsigned 1");
79 check(int64(1), "signed64 1");
80 check(uint64(1), "unsigned64 1");
81 check(1.5, "default 1.5");
82 check(nil, "nil <nil>");
83}
84