mirror of
https://github.com/golang/go
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47 lines
863 B
Go
47 lines
863 B
Go
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// run -gcflags=-G=3
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// Copyright 2021 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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package main
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import (
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"fmt"
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"strconv"
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"strings"
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)
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type Stringer interface {
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String() string
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}
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// stringableList is a slice of some type, where the type
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// must have a String method.
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type stringableList[T Stringer] []T
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func (s stringableList[T]) String() string {
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var sb strings.Builder
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for i, v := range s {
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if i > 0 {
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sb.WriteString(", ")
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}
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sb.WriteString(v.String())
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}
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return sb.String()
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}
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type myint int
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func (a myint) String() string {
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return strconv.Itoa(int(a))
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}
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func main() {
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v := stringableList[myint]{ myint(1), myint(2) }
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if got, want := v.String(), "1, 2"; got != want {
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panic(fmt.Sprintf("got %s, want %s", got, want))
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}
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}
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