[Review] SE-0088: Modernize libdispatch for Swift 3 naming conventions


(Dan Appel) #1

Hello Swift community,

The review of "SE-0088: Modernize libdispatch for Swift 3 naming

conventions" begins now and runs through May 17. The proposal is available
here:

https://github.com/apple/swift-evolution/blob/master/proposals/0088-libdispatch-for-swift3.md

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* Is the problem being addressed significant enough to warrant a change

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Thank you,

-Chris Lattner
Review Manager

Ok, I have mixed feeling about this proposal.

First, this is a huge breaking change, and it doesn’t really have to be
one. The current SPM convention is to prefix C libraries with Lib.
Following this convention, Dispatch (the C version) would be renamed to
LibDispatch, and this new wrapper library would be called just Dispatch.
With this setup, the old C api would still be there (under the module
LibDispatch), which makes migration much easier. In the proposal, this
issue is not addressed at all and it even says that all code using
libdispatch would have to be rewritten. That is not ok.

Another issues is the proposal to 'automagically' translate the C api into
Swift. There are many libraries right now that wrap the current libdispatch
functions and provide a similar api, and I don’t think there’s any reason
why this shouldn’t be done the same way. I would also argue that doing this
links the Swift language to libdispatch in a way that isn’t necessary. For
example, there is a library called Venice
<https://github.com/VeniceX/Venice> which provides CSP (go-style
concurrency) for Swift by wrapping a fork of the C library libmill, and it
doesn’t do any of the proposed magic importing of any sort. I don’t see a
reason why libdispatch shouldn’t take the same approach.

Overall, I think the idea is good but some of the details are really
lacking. As it stands, I would vote to reject this proposal and request
revision, or reject it outright and suggest to use third-party wrappers
around libdispatch (which is what the community is currently doing).

Dan Appel

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Dan Appel