That’s cool, but a hygienic macro system isn’t anywhere on the Swift roadmap.
Chris has mentioned in interviews that such a system is "a big feature that’s open-ended and requires a huge design process” which makes off-the-table for Swift 5, and (I’m guessing) unlikely for Swift 6 too. Personally I’d like to be able to better debug my apps in Swift 4.1 rather than waiting another 2 or 3 years for a magical macro system to somehow solve this. Dave > On Nov 2, 2017, at 6:50 PM, Eric Summers <eric_summ...@icloud.com> wrote: > > I think this makes more sense as part of a hygienic macro system. These > “hidden” parameters could be made available to standard functions using some > sort of convention to exclude them from autocompletion. > > Eric > >> On Nov 2, 2017, at 8:35 PM, Tony Allevato via swift-evolution >> <swift-evolution@swift.org <mailto:swift-evolution@swift.org>> wrote: >> >> I like this idea as it's presented here, for the debugging/logging reasons >> that you stated. >> >> Should we tighten the shackles a little be to validate that *only* the >> special #file/#line/#function directives can be permitted for these extra >> parameters? I'm struggling to think of a case where we would want to allow >> something else, since there's no way to provide the values for them in a >> standard call. >> >> >> On Thu, Nov 2, 2017 at 5:26 PM Dave DeLong via swift-evolution >> <swift-evolution@swift.org <mailto:swift-evolution@swift.org>> wrote: >> Hi SE, >> >> As I’ve been using my own custom operators like “?!”, “!!”, or operators >> provided by libraries (<|, ~>, etc), I’ve often wanted to capture the #file >> and #line where the operators are used to make debugging their use a lot >> easier. >> >> For example, given something the unwrap-or-die operator >> (https://github.com/erica/swift-evolution/blob/2c1be72e34c970894e4ba7ed9df5cee3298d4282/proposals/XXXX-unwrap-or-die.md >> >> <https://github.com/erica/swift-evolution/blob/2c1be72e34c970894e4ba7ed9df5cee3298d4282/proposals/XXXX-unwrap-or-die.md>), >> you’d want to capture the #file and #line so you could pass it on to the >> underlying call to fatalError(). >> >> Or, if you’re using a custom bind operator and something goes wrong, it’d be >> great to be able to capture the file and line where the operator is used so >> you can quickly triage the bug in your code. >> >> Unfortunately, Swift has the hard limit the the implementations of unary >> operators may have one-and-only-one parameter, and that binary operators may >> only have two parameters. >> >> I’d like to propose a very minor change to Swift, whereby operator >> implementations may have more than their one or two parameters, provided >> that all subsequent parameters come with a default value. This would make it >> trivial to add in #file, #line, #function, etc to your operator >> implementations, which you can then capture for your own purposes. >> >> An implementation of this change, with passing tests, can be found here: >> https://github.com/davedelong/swift/commit/c65c634a59b63add0dc9df1ac8803e9d70bfa697 >> >> <https://github.com/davedelong/swift/commit/c65c634a59b63add0dc9df1ac8803e9d70bfa697> >> >> Dave >> _______________________________________________ >> swift-evolution mailing list >> swift-evolution@swift.org <mailto:swift-evolution@swift.org> >> https://lists.swift.org/mailman/listinfo/swift-evolution >> <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 >
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