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// $G $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 "os"
const (
Bool = iota
Int
Float
String
Struct
Chan
Array
Map
Func
Last
)
type S struct {
a int
}
var s S = S{1234}
var c = make(chan int)
var a = []int{0, 1, 2, 3}
var m = make(map[string]int)
func assert(b bool, s string) {
if !b {
println(s)
os.Exit(1)
}
}
func f(i int) interface{} {
switch i {
case Bool:
return true
case Int:
return 7
case Float:
return 7.4
case String:
return "hello"
case Struct:
return s
case Chan:
return c
case Array:
return a
case Map:
return m
case Func:
return f
}
panic("bad type number")
}
func main() {
for i := Bool; i < Last; i++ {
switch x := f(i).(type) {
case bool:
assert(x == true && i == Bool, "bool")
case int:
assert(x == 7 && i == Int, "int")
case float64:
assert(x == 7.4 && i == Float, "float64")
case string:
assert(x == "hello" && i == String, "string")
case S:
assert(x.a == 1234 && i == Struct, "struct")
case chan int:
assert(x == c && i == Chan, "chan")
case []int:
assert(x[3] == 3 && i == Array, "array")
case map[string]int:
assert(x == m && i == Map, "map")
case func(i int) interface{}:
assert(x == f && i == Func, "fun")
default:
assert(false, "unknown")
}
}
// boolean switch (has had bugs in past; worth writing down)
switch {
case true:
assert(true, "switch 2 bool")
default:
assert(false, "switch 2 unknown")
}
switch true {
case true:
assert(true, "switch 3 bool")
default:
assert(false, "switch 3 unknown")
}
switch false {
case false:
assert(true, "switch 4 bool")
default:
assert(false, "switch 4 unknown")
}
}
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