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

[Karl Wagner]

-1. I'm not enthusiastic about using ~=. IMO it's only a small improvement over the "if case let..." hieroglyphics and still too cryptic.
  

  
Like the others, I really like "matches" or some other, more explicit, keyword.
  

  
Anything more general around pattern-matching should probably wait until we start adding language support for regexes and other complex patterns. Then we can make something that is more logically consistent.
  

    
  
  
  

  
  
  
  

  
  
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> On Oct 24, 2016 at 10:55 pm,  <Haravikk via swift-evolution (mailto:swift-evolution at swift.org)>  wrote:
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> > On 24 Oct 2016, at 21:38, Martin Waitz via swift-evolution  <swift-evolution at swift.org (mailto:swift-evolution at swift.org)>  wrote:
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> > Hi,
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> >  When using a pattern match operator, I’d prefer to reverse its arguments:
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> >         if value matches pattern …
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> >         if result =~ .success(let x) { use(x) }
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> >  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.       
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> 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:
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> if result matches .success(let x) { use(x) }
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> if result matches let x? { use(x) }
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> 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:
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> if result is let x? { use(x) }
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> 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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