I share your concern about trailingZeros and leadingZeros; those could probably be improved as trailingZeroBits and leadingZeroBits. The terms of art there, ctz ("count trailing zeros") and clz, are a bit cryptic but perhaps also fine if ulp is acceptable for FloatingPoint.<br><br><br><br><div class="gmail_quote"><div dir="ltr">On Sun, Jan 29, 2017 at 22:42 Brent Royal-Gordon via swift-evolution <<a href="mailto:swift-evolution@swift.org">swift-evolution@swift.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">> On Jan 29, 2017, at 7:02 PM, Dave Abrahams via swift-evolution <<a href="mailto:swift-evolution@swift.org" class="gmail_msg" target="_blank">swift-evolution@swift.org</a>> wrote:<br class="gmail_msg">
><br class="gmail_msg">
>>> var popcount: Int { get }<br class="gmail_msg">
>><br class="gmail_msg">
>> I'm not super-fond of this name; I assume it's a term of art, but it's<br class="gmail_msg">
>> a pretty obscure one. Maybe `numberOfOnes`? `onesWithin`?<br class="gmail_msg">
><br class="gmail_msg">
> Yes, the rationale is that it's a term of art. I think if you were<br class="gmail_msg">
> going to call it something else, you'd need to mention "one _bits_" in<br class="gmail_msg">
> the name. If we can come up with a name that's obviously better, that's<br class="gmail_msg">
> great, but lacking a clear winner we should go with the already-accepted<br class="gmail_msg">
> term.<br class="gmail_msg">
<br class="gmail_msg">
Okay, but the same could be said for `trailingZeros`. Does that also need to be something like `trailingZerosInBinaryRepresentation` or what-have-you?<br class="gmail_msg">
<br class="gmail_msg">
>> It might make a great deal of sense to support bitwise operations on<br class="gmail_msg">
>> this type,<br class="gmail_msg">
><br class="gmail_msg">
> I think that's a model of SetAlgebra, then, isn't it?<br class="gmail_msg">
<br class="gmail_msg">
Hmm, arguably. It's a shame that we won't be able to use it with things like `OptionSet`, though.<br class="gmail_msg">
<br class="gmail_msg">
> Personally I don't think the strict separation of SetAlgebra and things<br class="gmail_msg">
> that do bitwise operations makes sense, but I know some people feel<br class="gmail_msg">
> strongly that it would be confusing for users to expose set operations<br class="gmail_msg">
> with bitwise operator names. IMO using | for union and & for<br class="gmail_msg">
> intersection would be beautiful. But that's a story for another day...<br class="gmail_msg">
<br class="gmail_msg">
<br class="gmail_msg">
Honestly, if I were designing Swift from scratch, I might consider having a `BitView` type and `bits` member which acts as a collection of `Bool`s (or maybe a set of offsets of `1` bits?) and conforms to `SetAlgebra`; you could then perform bitwise operations through the `bits`, but not directly on the value itself. But that ship has clearly sailed.<br class="gmail_msg">
<br class="gmail_msg">
--<br class="gmail_msg">
Brent Royal-Gordon<br class="gmail_msg">
Architechies<br class="gmail_msg">
<br class="gmail_msg">
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</blockquote></div>