[swift-evolution] Code comments that check code validity.

[Xiaodi Wu]

On Sat, Jan 14, 2017 at 5:35 PM, Amir Michail <a.michail at me.com> wrote:

>
> > On Jan 14, 2017, at 6:28 PM, Xiaodi Wu <xiaodi.wu at gmail.com> wrote:
> >
> > This has been brought up on this list before. The conclusion of the
> previous thread on this topic was that there is a way to do this:
> >
> > #if false
> > // put your code here
> > #endif
> >
>
> This would not check the code for compilability within the surrounding
> code. This requires more than a syntax check.


I can't say I've ever needed that feature; could you share a concrete use
case?

In any case, if you put code in a function that's not exported and never
invoked, I believe you would achieve the desired effect. Within the body of
a function, you could do so in a closure.

```
func foo() {
  // code you want to run
  _ = {
    // code you don't intend to run
  }
  // more code you want to run
}
```

> It does not allow you to comment out fragments of a single statement, but
> the incremental value of devoting time to additionally support that is, it
> would seem, low.
> >
> > On Sat, Jan 14, 2017 at 17:18 Amir Michail via swift-evolution <
> swift-evolution at swift.org> wrote:
> > The code in a “code comment" must compile (not just be syntactically
> correct) yet must not have any effect on the resulting executable.
> >
> > For example, commented entries in an array would be checked for
> compilability but would not be included in the executable.
> >
> > Such “code comments" would allow you to have code/data that is currently
> unused but is constantly checked to be valid just in case you want to use
> it in the future.
> >
> > _______________________________________________
> > swift-evolution mailing list
> > swift-evolution at swift.org
> > https://lists.swift.org/mailman/listinfo/swift-evolution
>
>
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