SE-0289: Function Builders

[James_Dempsey]

@toph42

Does anyone actually have another builder incarnation in mind that precludes using plain old @builder as the attribute name, or is avoiding that purely a theoretical future-proofing? I find the various arguments for @resultBuilder as the name compelling, if @builder is off the table for being too broad.

(First, sorry for the deleted messages, I had meant this post to reply directly and got all fouled up trying to fix it.)

For me, it's less about any specific future language feature and more that the Builder design pattern is already widely used in Swift code in contexts outside of this feature.

Doing a quick search on GitHub for Swift source files with the term 'builder' but excluding the term '_functionBuilder' shows over 54,000 source files using the term. (The number varies per search for some reason. 54K+ was the low number, 80K+ was the high number)

This includes types like PathBuilder, AttributedStringBuilder, AdvertisementsBuilder, MerchantRequestBuilder.

I haven't done a comprehensive, file by file inspection, but the name and concept of 'builder' is already in widespread use in Swift code beyond the usage of this feature, and I would imagine builders that don't use this feature will continue to be created by Swift developers.