[swift-evolution] [Pitch] Reimagining guard case/if case

[Haravikk]

> On 24 Oct 2016, at 21:38, Martin Waitz via swift-evolution <swift-evolution at swift.org> wrote:
> 
> Hi,
> 
> When using a pattern match operator, I’d prefer to reverse its arguments:
> 
>    if value matches pattern …
> 
>    if result =~ .success(let x) { use(x) }
> 
> Being used to pattern matching in functional languages, I also do like our current syntax.
> Using ~= together with `let` on the left looks very strange to me.

That's interesting point, it does kind of make more sense that way round, but I wonder if we were to d that a keyword might be even better than an operate, like:

	if result matches .success(let x) { use(x) }
	if result matches let x? { use(x) }

And so-on? Maybe matches isn't the right keyword; we could even re-use the is keyword for something shorter (and just think of a type as a form of pattern)? I could like the idea of doing:

	if result is let x? { use(x) }

My reasoning being that a keyword makes it much more obvious what's going on as it can read like natural language to convey that it's a form of matching, wheres ~= as an operator still requires some learning if you've not seen something similar in another language.
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