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