1// Copyright 2023 The Go Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style
3// license that can be found in the LICENSE file.
4
5package versions
6
7// This file contains predicates for working with file versions to
8// decide when a tool should consider a language feature enabled.
9
10// GoVersions that features in x/tools can be gated to.
11const (
12	Go1_18 = "go1.18"
13	Go1_19 = "go1.19"
14	Go1_20 = "go1.20"
15	Go1_21 = "go1.21"
16	Go1_22 = "go1.22"
17)
18
19// Future is an invalid unknown Go version sometime in the future.
20// Do not use directly with Compare.
21const Future = ""
22
23// AtLeast reports whether the file version v comes after a Go release.
24//
25// Use this predicate to enable a behavior once a certain Go release
26// has happened (and stays enabled in the future).
27func AtLeast(v, release string) bool {
28	if v == Future {
29		return true // an unknown future version is always after y.
30	}
31	return Compare(Lang(v), Lang(release)) >= 0
32}
33
34// Before reports whether the file version v is strictly before a Go release.
35//
36// Use this predicate to disable a behavior once a certain Go release
37// has happened (and stays enabled in the future).
38func Before(v, release string) bool {
39	if v == Future {
40		return false // an unknown future version happens after y.
41	}
42	return Compare(Lang(v), Lang(release)) < 0
43}
44