mirror of https://github.com/golang/go.git
49 lines
1.0 KiB
Plaintext
49 lines
1.0 KiB
Plaintext
// run
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// Copyright 2020 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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type Gen[A any] func() (A, bool)
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func combine[T1, T2, T any](g1 Gen[T1], g2 Gen[T2], join func(T1, T2) T) Gen[T] {
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return func() (T, bool) {
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var t T
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t1, ok := g1()
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if !ok {
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return t, false
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}
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t2, ok := g2()
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if !ok {
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return t, false
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}
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return join(t1, t2), true
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}
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}
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type Pair[A, B any] struct {
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A A
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B B
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}
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func NewPair[A, B any](a A, b B) Pair[A, B] { return Pair[A, B]{a, b} }
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func Combine2[A, B any](ga Gen[A], gb Gen[B]) Gen[Pair[A, B]] {
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return combine(ga, gb, NewPair(A, B))
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}
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func main() {
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var g1 Gen[int] = func() (int, bool) { return 3, true }
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var g2 Gen[string] = func() (string, bool) { return "x", false }
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gc := combine(g1, g2, NewPair[int, string])
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gc2 := Combine2(g1, g2)
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if got, ok := gc(); ok {
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panic(got)
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}
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if got2, ok := gc2(); ok {
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panic(got2)
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}
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}
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