[Pitch] #if swift version with third version component


(Richard Wei) #1

Hi,

Foundation in 3.0-RELEASE didn't fully resolve the renaming in SE-0086, so we have `RegularExpression` on Linux and `NSRegularExpression` on macOS. The naming is now unified in Swift 3.0.1, but there doesn’t seem to be a possible way to resolve the code breaking change. Consider the example below:

Currently the following code is only compatible with 3.0-RELEASE, because RegularExpression on Linux becomes NSRegularExpression in 3.0.1, while we cannot use `#if` to differentiate between 3.0 and 3.0.1.

  #if !os(macOS)
  let regex = try RegularExpression(pattern: pattern, options: [ .dotMatchesLineSeparators ])
  #else
  let regex = try NSRegularExpression(pattern: pattern, options: [ .dotMatchesLineSeparators ])
  #endif

Proposed solution:

If `#if swift(>=)` can take the third version component, we can make the code compatible with 3.0.1 by the following:

  #if os(macOS) || swift(>=3.0.1)
  let regex = try NSRegularExpression(pattern: pattern, options: [ .dotMatchesLineSeparators ])
  #else
  let regex = try RegularExpression(pattern: pattern, options: [ .dotMatchesLineSeparators ])
  #endif

Additionally, we can consider supporting the == operator, so that checking only the version with inconsistent naming is sufficient:

  #if !os(macOS) && swift(==3.0.0)
  let regex = try RegularExpression(pattern: pattern, options: [ .dotMatchesLineSeparators ])
  #else
  let regex = try NSRegularExpression(pattern: pattern, options: [ .dotMatchesLineSeparators ])
  #endif

Impact on existing code:

`#if swift(>=X.X.X)` and `#if swift(==X.X.X)` are purely additive.

-Richard


(Chris Lattner) #2

Hi,

Foundation in 3.0-RELEASE didn't fully resolve the renaming in SE-0086, so we have `RegularExpression` on Linux and `NSRegularExpression` on macOS. The naming is now unified in Swift 3.0.1, but there doesn’t seem to be a possible way to resolve the code breaking change. Consider the example below:

+1. Assuming there are no major objections, I don’t think this needs a full evolution cycle. This seems like a bug fix to me.

-Chris

···

On Oct 22, 2016, at 2:44 PM, Richard Wei via swift-evolution <swift-evolution@swift.org> wrote:

Currently the following code is only compatible with 3.0-RELEASE, because RegularExpression on Linux becomes NSRegularExpression in 3.0.1, while we cannot use `#if` to differentiate between 3.0 and 3.0.1.

  #if !os(macOS)
  let regex = try RegularExpression(pattern: pattern, options: [ .dotMatchesLineSeparators ])
  #else
  let regex = try NSRegularExpression(pattern: pattern, options: [ .dotMatchesLineSeparators ])
  #endif

Proposed solution:

If `#if swift(>=)` can take the third version component, we can make the code compatible with 3.0.1 by the following:

  #if os(macOS) || swift(>=3.0.1)
  let regex = try NSRegularExpression(pattern: pattern, options: [ .dotMatchesLineSeparators ])
  #else
  let regex = try RegularExpression(pattern: pattern, options: [ .dotMatchesLineSeparators ])
  #endif

Additionally, we can consider supporting the == operator, so that checking only the version with inconsistent naming is sufficient:

  #if !os(macOS) && swift(==3.0.0)
  let regex = try RegularExpression(pattern: pattern, options: [ .dotMatchesLineSeparators ])
  #else
  let regex = try NSRegularExpression(pattern: pattern, options: [ .dotMatchesLineSeparators ])
  #endif

Impact on existing code:

`#if swift(>=X.X.X)` and `#if swift(==X.X.X)` are purely additive.

-Richard

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(Alex Martini) #3

When you file the bug, can you post the Jira number? The grammar in TSPL will also need to be changed to accept three version components.

https://developer.apple.com/library/content/documentation/Swift/Conceptual/Swift_Programming_Language/Statements.html#//apple_ref/swift/grammar/swift-version

Thanks!
— Alex

···

On Oct 23, 2016, at 9:25 PM, Chris Lattner via swift-evolution <swift-evolution@swift.org> wrote:

On Oct 22, 2016, at 2:44 PM, Richard Wei via swift-evolution <swift-evolution@swift.org <mailto:swift-evolution@swift.org>> wrote:

Hi,

Foundation in 3.0-RELEASE didn't fully resolve the renaming in SE-0086, so we have `RegularExpression` on Linux and `NSRegularExpression` on macOS. The naming is now unified in Swift 3.0.1, but there doesn’t seem to be a possible way to resolve the code breaking change. Consider the example below:

+1. Assuming there are no major objections, I don’t think this needs a full evolution cycle. This seems like a bug fix to me.

-Chris

Currently the following code is only compatible with 3.0-RELEASE, because RegularExpression on Linux becomes NSRegularExpression in 3.0.1, while we cannot use `#if` to differentiate between 3.0 and 3.0.1.

  #if !os(macOS)
  let regex = try RegularExpression(pattern: pattern, options: [ .dotMatchesLineSeparators ])
  #else
  let regex = try NSRegularExpression(pattern: pattern, options: [ .dotMatchesLineSeparators ])
  #endif

Proposed solution:

If `#if swift(>=)` can take the third version component, we can make the code compatible with 3.0.1 by the following:

  #if os(macOS) || swift(>=3.0.1)
  let regex = try NSRegularExpression(pattern: pattern, options: [ .dotMatchesLineSeparators ])
  #else
  let regex = try RegularExpression(pattern: pattern, options: [ .dotMatchesLineSeparators ])
  #endif

Additionally, we can consider supporting the == operator, so that checking only the version with inconsistent naming is sufficient:

  #if !os(macOS) && swift(==3.0.0)
  let regex = try RegularExpression(pattern: pattern, options: [ .dotMatchesLineSeparators ])
  #else
  let regex = try NSRegularExpression(pattern: pattern, options: [ .dotMatchesLineSeparators ])
  #endif

Impact on existing code:

`#if swift(>=X.X.X)` and `#if swift(==X.X.X)` are purely additive.

-Richard

_______________________________________________
swift-evolution mailing list
swift-evolution@swift.org <mailto:swift-evolution@swift.org>
https://lists.swift.org/mailman/listinfo/swift-evolution

_______________________________________________
swift-evolution mailing list
swift-evolution@swift.org <mailto:swift-evolution@swift.org>
https://lists.swift.org/mailman/listinfo/swift-evolution