features.go

     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  
     5  package 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  // named constants, to avoid misspelling
    11  const (
    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  	Go1_23 = "go1.23"
    18  	Go1_24 = "go1.24"
    19  	Go1_25 = "go1.25"
    20  	Go1_26 = "go1.26"
    21  )
    22  
    23  // Future is an invalid unknown Go version sometime in the future.
    24  // Do not use directly with Compare.
    25  const Future = ""
    26  
    27  // AtLeast reports whether the file version v comes after a Go release.
    28  //
    29  // Use this predicate to enable a behavior once a certain Go release
    30  // has happened (and stays enabled in the future).
    31  func AtLeast(v, release string) bool {
    32  	if v == Future {
    33  		return true // an unknown future version is always after y.
    34  	}
    35  	return Compare(Lang(v), Lang(release)) >= 0
    36  }
    37  
    38  // Before reports whether the file version v is strictly before a Go release.
    39  //
    40  // Use this predicate to disable a behavior once a certain Go release
    41  // has happened (and stays enabled in the future).
    42  func Before(v, release string) bool {
    43  	if v == Future {
    44  		return false // an unknown future version happens after y.
    45  	}
    46  	return Compare(Lang(v), Lang(release)) < 0
    47  }
    48
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