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https://github.com/golang/go
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85 lines
1.6 KiB
Go
85 lines
1.6 KiB
Go
// run
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// Copyright 2009 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// Test simple type switches on basic types.
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package main
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import "fmt"
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const (
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a = iota
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b
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c
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d
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e
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)
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var x = []int{1, 2, 3}
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func f(x int, len *byte) {
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*len = byte(x)
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}
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func whatis(x interface{}) string {
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switch xx := x.(type) {
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default:
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return fmt.Sprint("default ", xx)
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case int, int8, int16, int32:
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return fmt.Sprint("signed ", xx)
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case int64:
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return fmt.Sprint("signed64 ", int64(xx))
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case uint, uint8, uint16, uint32:
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return fmt.Sprint("unsigned ", xx)
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case uint64:
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return fmt.Sprint("unsigned64 ", uint64(xx))
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case nil:
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return fmt.Sprint("nil ", xx)
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}
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panic("not reached")
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}
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func whatis1(x interface{}) string {
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xx := x
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switch xx.(type) {
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default:
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return fmt.Sprint("default ", xx)
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case int, int8, int16, int32:
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return fmt.Sprint("signed ", xx)
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case int64:
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return fmt.Sprint("signed64 ", xx.(int64))
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case uint, uint8, uint16, uint32:
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return fmt.Sprint("unsigned ", xx)
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case uint64:
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return fmt.Sprint("unsigned64 ", xx.(uint64))
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case nil:
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return fmt.Sprint("nil ", xx)
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}
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panic("not reached")
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}
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func check(x interface{}, s string) {
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w := whatis(x)
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if w != s {
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fmt.Println("whatis", x, "=>", w, "!=", s)
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panic("fail")
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}
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w = whatis1(x)
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if w != s {
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fmt.Println("whatis1", x, "=>", w, "!=", s)
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panic("fail")
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}
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}
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func main() {
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check(1, "signed 1")
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check(uint(1), "unsigned 1")
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check(int64(1), "signed64 1")
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check(uint64(1), "unsigned64 1")
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check(1.5, "default 1.5")
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check(nil, "nil <nil>")
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}
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