[swift-evolution] [Pitch] Renaming sizeof, sizeofValue, strideof, strideofValue

[Dave Abrahams]

on Thu Jun 02 2016, John McCall <swift-evolution at swift.org> wrote:

>  On Jun 2, 2016, at 1:43 PM, Russ Bishop <xenadu at gmail.com> wrote:
>
>  On Jun 2, 2016, at 11:30 AM, John McCall via swift-evolution <swift-evolution at swift.org>
>  wrote:
>
>  I still think the value-based APIs are misleading and that it would be better to ask people to just use a type explicitly.
>
>  John.
>
>  I agree; in fact why aren’t these properties on the type itself? The type is what matters; why can’t the type just tell me it’s size? 
>  Having free functions or magic operators seems to be another holdover from C. 
>
>  Int.size
>  Int.alignment
>  Int.spacing
>
>  let x: Any = 5
>  type(of: x).size
>
>  The compiler should be able to statically know the first three values and inline them. The second is discovering the size dynamically.
>
> Two reasons. The first is that this is a user-extensible namespace via
> static members, so it's somewhat unfortunate to pollute it with names
> from the library. The second is that there's currently no language
> mechanism for adding a static member to every type, so this would have
> to be built-in. 

More fundamental reasons:


* `Array<Int>.size` is easily misinterpreted.  The identifier
  `MemoryLayout` was suggested in order to set the proper mental context
  at the use site.

* I don't want “size,” “alignment,” and “spacing” appearing in the
  code-completion list for every type.  

* I can easily imagine users wanting to use static properties by these
  names for their own types, with completely different meaning.

> But I agree that in the abstract a static property would be
> preferable.
>
> John.
>
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-- 
-Dave