[swift-evolution] Trial balloon: conforming sizeof, sizeofValue, etc. to naming guidelines

[Xiaodi Wu]

I like it, but how do you accommodate sizeofValue, etc?
On Mon, May 2, 2016 at 11:46 Dave Abrahams <dabrahams at apple.com> wrote:

>
> on Sun May 01 2016, Xiaodi Wu <xiaodi.wu-AT-gmail.com> wrote:
>
> > It's a bad habit of mine, I guess, to err on the side of suggesting
> conservative
> > changes on the assumption that it'll be maximally acceptable. If there's
> > appetite for a more serious renaming, and as you say these are considered
> > relatively rarely used, then it's a world of possibility!
> >
> > We could do as Shawn suggested and follow precedent in some other
> languages by
> > moving these functions out of the global scope. Perhaps these will meet
> with
> > some satisfaction:
> >
> > ```
> > Memory.footprint(of:)
> > Memory.alignment(of:)
> > Memory.spacing(of:)
> > ```
>
> I'd rather have
>
> MemoryLayout<T>.size
> MemoryLayout<T>.alignment
> MemoryLayout<T>.spacing
>
> -Dave
>
> > On Sun, May 1, 2016 at 21:41 Dave Abrahams via swift-evolution
> > <swift-evolution at swift.org> wrote:
> >
> >     on Sun May 01 2016, Xiaodi Wu <swift-evolution at swift.org> wrote:
> >
> >     > On Sun, May 1, 2016 at 7:00 PM, Dave Abrahams via swift-evolution
> >     > <swift-evolution at swift.org> wrote:
> >     >
> >     > on Thu Apr 28 2016, Xiaodi Wu
> >     > <swift-evolution at swift.org> wrote:
> >     >
> >     > > We all know and love sizeof(), but given that it's different
> from its C
> >     > > counterpart anyway, shouldn't these conform to Swift naming
> guidelines?
> >     In
> >     > other
> >     > > words, after SE-0006, shouldn't these names be as follows?
> >     > >
> >     > > ```
> >     > > size<T>(of: T.Type)
> >     > > size<T>(ofValue: T)
> >     > > stride<T>(of: T.Type)
> >     > > stride<T>(ofValue: T)
> >     > > align<T>(of: T.Type)
> >     > > align<T>(ofValue: T)
> >     > > ```
> >     > >
> >     > > There are obvious issues with two different things named
> `stride`, but
> >     IMO
> >     > > that's best addressed by renaming one of them; the real problem
> is that
> >     > the word
> >     > > stride is used in two different ways already. Thoughts?
> >     >
> >     > These functions correspond to C and LLVM primitives and we
> consciously
> >     > kept those names because they are terms of art.
> >     >
> >     > I recognize that this was the intention behind preserving the
> names as-is.
> >     The
> >     > thought process behind proposing a renaming was as follows:
> >     >
> >     > * The Swift counterpart to C `sizeof()` is `strideof(_:)`. Thus,
> although
> >     the
> >     > *names* are treated as terms of art, not all of them are used to
> mean the
> >     art
> >     > for which they are terms (if you will).
> >
> >     The specific meaning of sizeof in Swift comes from either LLVM or
> from
> >     SIL, IIRC. It predates me, but it's supposed to correspond to what
> the
> >     IRGen level of the compiler calls “sizeof.”
> >
> >     > To reinforce the separation between C primitives and these Swift
> >     > functions, C `offsetof()` has no Swift counterpart.
> >
> >     Yes, that's part of the reason I'd very much like to choose more
> >     descriptive names if we are going to move away from the current
> >     spellings. moving the parenthesis is a pretty weak cue that this
> thing
> >     might be slightly different.
> >
> >     > * A survey of other languages suggests that, as terms of art,
> these names
> >     are
> >     > not always treated as a single word but as a phrase, by which I
> mean that
> >     the
> >     > preposition "of" can be subject to language-specific naming
> conventions.
> >     For
> >     > example, in Rust you have `size_of()`, `size_of_val()`, etc.; in
> the .NET
> >     > Framework, you have the `Marshal.SizeOf()` method; and even in
> LLVM you
> >     > apparently have (and this is based just on googling--my level of
> >     familiarity
> >     > with LLVM is low to nonexistent) struct `AlignOf<T>`.
> >     >
> >     > I don't know that
> >     >
> >     > size(of: T.self)
> >     >
> >     > is particularly descriptive usage, and if we were going to change
> them
> >     > so they didn't look like sizeof, strideof, alignof I'd want to
> make them
> >     > far more descriptive. E.g.
> >     >
> >     > memoryFootprint(Int.self)
> >     >
> >     > or
> >     >
> >     > bytesRequiredForStorage(Int.self)
> >     > standardByteAlignment(Int.self)
> >     > bytesBetweenArrayElements(Int.self)
> >     >
> >     > etc.
> >     >
> >     > To my mind, `size(of:)` is not moving away from using a term of
> art but
> >     rather
> >     > following existing precedent in conforming use of the preposition
> to
> >     > language-specific conventions.
> >
> >     The same argument could be made for “mapped” and “reduced.”
> >
> >     > Like you, I would be hesitant to suggest moving away from these
> terms
> >     > of art altogether.
> >
> >     You misunderstand me. I'm not hesitant about that at all. What I
> >     dislike is the idea of being close-to-but-not-quite-the-same as the
> >     source terms to which they correspond. The original terms are not
> >     great, and these facilities are seldom used. They can afford to be
> >     longer and more descriptive.
> >
> >     > I do think, though, that moving the preposition has the bonus of
> >     > visually suggesting however subtly that `size(of:) ` might have a
> >     > Swift-specific twist that makes it not a drop-in equivalent for C
> >     > `sizeof()`.
> >
> >     I don't think subtlety is a virtue in this case.
> >
> >     --
> >     Dave
> >
> >     _______________________________________________
> >     swift-evolution mailing list
> >     swift-evolution at swift.org
> >     https://lists.swift.org/mailman/listinfo/swift-evolution
> >
>
> --
> Dave
>
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