// $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 <nil>");
}
|