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Diffstat (limited to 'test/typeparam/stringable.go')
-rw-r--r-- | test/typeparam/stringable.go | 46 |
1 files changed, 46 insertions, 0 deletions
diff --git a/test/typeparam/stringable.go b/test/typeparam/stringable.go new file mode 100644 index 0000000..791b670 --- /dev/null +++ b/test/typeparam/stringable.go @@ -0,0 +1,46 @@ +// run + +// 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)) + } +} |