[swift-evolution] [Discussion] Parentheses

[Vladimir.S]

On 06.07.2016 3:57, Jens Persson via swift-evolution wrote:
> Please feel free to ignore this naive attempt to engage in this discussion.
>
> My understanding of the history of Swift's tuples, argument lists, pattern
> matching, associated values, etc. in two steps:
>
> 1. Initial Idealism *:
> Simple powerful heavily reused general concept.
>
> 2. Iterative pragmatism / reality *:
> Complicated (exceptions to) rules.
>
> (* Inevitably not taking everything in to account.)
>
> Has there been any recent attempts to outline a more or less complete
> redesign for these things, returning to step 1 so to speak, but taking into
> account what has now been learned?
>
>
> As a side note (and supposedly trivial to most but me):
>
> Parentheses (parenthesized expressions in the grammar?) are used for all of
> these parts of the language, and they probably should be, but perhaps the
> similarities and differences between the language constructs can be made
> clearer to see by pretending that argument and parameter lists are written
> with eg ≪≫ and tuples with eg ⊂⊃, etc.?
>
> For example, I think most people agree that we should be able to use
> "sloppy/forgiving" parenthetical grouping in code such as:
> ((1 + (2 * 3)) * (x + (-5))) - y
> This is fine and can be used to express meaning for the person
> reading/writing, even though it means that some of the parens can become
> superfluous to a machine interpretation.
>
> AFAICS this need not have anything to do with tuples and/or parameter
> lists, but the fact that Swift is treating eg:
> func foo(x: ((((Int))))) { print(x) }
> as
> func foo(x: Int) { print(x) }
> and
> ((Int, Int))
> as
> (Int, Int)

If SE-0110 will be accepted, ((Int, Int)) will mean "1 tuple with Int,Int 
fields" and (Int, Int) will mean only "list of two Ints in parameters"

> seems to suggest that it somehow does.
>
> Or maybe I have just forgotten the reasons for why there can be no such
> thing as (a nested) single element tuple (type).
>
> I also can't remember what the pros & cons of disallowing labeled single
> element tuples were.
>
> Happy to be corrected and pointed to relevant reading : )
>
> /Jens
>
>
>
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