[swift-evolution] [Proposal][Discussion] Deprecate Tuple Shuffles

Xiaodi Wu xiaodi.wu at gmail.com
Sat May 6 17:21:12 CDT 2017


To which human would it be misleading?

To the writer? No, because the compiler will warn you right away. By the
time you're done with writing the first line, it'll warn you that Int and
Double are unused variables. And if you try to use x and y, you get an
error.

To the reader? Only if the writer knowingly wrote this misleading code. In
other words, it's a nice puzzle, but no reader will encounter this in
real-world code, unless they're being tormented by the writer on purpose.
On Sat, May 6, 2017 at 16:28 Brent Royal-Gordon <brent at architechies.com>
wrote:

> > On May 5, 2017, at 11:06 PM, Xiaodi Wu <xiaodi.wu at gmail.com> wrote:
> >
> > The identifier after a colon is *never* a type in any pattern matching,
> and there's no need of which I'm aware to support type annotations in
> pattern matching. We put colons after labels, and the current syntax is
> perfectly consistent here. What is the defect you're trying to cure?
>
> The defect underlying this proposal: `let (x: Int, y: Double)` looks like
> it's declaring `x` and `y` of types `Int` and `Double`, but it's actually
> declaring `Int` and `Double` and binding them to `x` and `y`. Your code's
> meaning is perfectly unambiguous to the compiler, of course, but it's
> misleading to the human.
>
> --
> Brent Royal-Gordon
> Architechies
>
>
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