[swift-evolution] commas optional

Xiaodi Wu xiaodi.wu at gmail.com
Thu Oct 12 14:03:14 CDT 2017


Single elements can legally span multiple lines; this would be hugely
source breaking. What problem are you trying to solve?

On Thu, Oct 12, 2017 at 13:50 Dave Yost via swift-evolution <
swift-evolution at swift.org> wrote:

>
> Speaking as a huge fan of optional semicolons...
>
>
> This seems clear:
>
>      semicolon : sequence of statements
>   :: comma     : sequence of elements in an array literal
>
> and so it occurred to me that this should hold:
>
>      A semicolon : the last statement     on a line.
>   :: A comma     : the last array element on a line.
>
>   ∴  A comma after the last array element on a line should be optional.
>
> and these should be legal Swift:
>
>   let list = [
>       1
>       2
>   ]
>
>   let dict = [
>       1 : 2
>       2 : 3
>   ]
>
> equivalent to:
>
>   let list = [ 1, 2 ] ; let dict = [ 1 : 2, 2 : 3 ]
>
>
> Or, as the Language Reference would say:
>
> A semicolon (;) can optionally appear after any statement and is used to
> separate multiple statements if they appear on the same line.
>
>
> A comma (,) can optionally appear after any element of an array literal
> and is used to separate multiple elements if they appear on the same line.
>
>
> Or:
>
> A semicolon (;) separates statements but is optional after the last
> statement on a line.
>
>
> A comma (,) separates elements of an array literal but is optional after
> the last element on a line.
>
>
>
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> swift-evolution at swift.org
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>
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