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// 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 (
"errors"
"fmt"
)
type Option[T any] struct {
ok bool
val T
}
func (o Option[T]) String() string {
if o.ok {
return fmt.Sprintf("Some(%v)", o.val)
}
return "None"
}
func Some[T any](val T) Option[T] { return Option[T]{ok: true, val: val} }
func None[T any]() Option[T] { return Option[T]{ok: false} }
type Result[T, E any] struct {
ok bool
val T
err E
}
func (r Result[T, E]) String() string {
if r.ok {
return fmt.Sprintf("Ok(%v)", r.val)
}
return fmt.Sprintf("Err(%v)", r.err)
}
func Ok[T, E any](val T) Result[T, E] { return Result[T, E]{ok: true, val: val} }
func Err[T, E any](err E) Result[T, E] { return Result[T, E]{ok: false, err: err} }
func main() {
a := Some[int](1)
b := None[int]()
fmt.Println(a, b)
x := Ok[int, error](1)
y := Err[int, error](errors.New("test"))
fmt.Println(x, y)
// fmt.Println(x)
_, _, _, _ = a, b, x, y
}
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