{"id":40684,"date":"2023-09-19T15:50:35","date_gmt":"2023-09-19T19:50:35","guid":{"rendered":"https:\/\/mjtsai.com\/blog\/?p=40684"},"modified":"2023-10-11T16:44:05","modified_gmt":"2023-10-11T20:44:05","slug":"swift-5-9","status":"publish","type":"post","link":"https:\/\/mjtsai.com\/blog\/2023\/09\/19\/swift-5-9\/","title":{"rendered":"Swift 5.9"},"content":{"rendered":"

Alexander Sandberg and Holly Borla<\/a> (tweet<\/a>, Hacker<\/a> News<\/a>):<\/p>\n

This is a major new release that adds an expressive macro system to the language and introduces support for integrating Swift into C++ codebases through bidirectional interoperability.<\/p>

It also introduces parameter packs, an improved expression evaluator while debugging, enhanced crash handling, Windows platform improvements, and more.<\/p>

[…]<\/p>

The new consume<\/code> operator<\/a> tells Swift to deinitialize a variable and transfer its contents without copying it. The consuming<\/code> and borrowing<\/code> parameter modifiers<\/a> provide hints that Swift can use to eliminate unnecessary copying and reference-counting operations when passing a parameter.<\/p><\/blockquote>\n

I have not been following this closely, but as far as I can tell this is for optimizations in code that you write. It doesn’t help when your code is being called by the standard library. If you try to iterate a Sequence<\/code> or sort an Array<\/code> of custom objects, I think it’s still going to do lots of unnecessary reference-counting.<\/p>\n

Finally, noncopyable structs and enums<\/a> allow you to create types which, like a class, can’t be meaningfully copied when assigned, but like a struct or enum, do not need to be reference-counted because only one storage location can own the instance at a time.<\/p>

[…]<\/p>