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> 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 > https://lists.swift.org/mailman/listinfo/swift-evolution
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