Howard, the point I am raising is that `0...(-9)` is not valid Swift because the first, "lower" bound is enforced to be less than the second, "upper" bound.<br><br>The problem is that with that restriction certain types of half-open intervals, namely those where the lower bound is the one being excluded, cannot be represented as a Range either currently or in Dave A's branch.<br><div class="gmail_quote"><div dir="ltr">On Tue, Apr 5, 2016 at 3:30 PM Howard Lovatt <<a href="mailto:howard.lovatt@gmail.com">howard.lovatt@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">I much prefer <font size="2"><span style="background-color:rgba(255,255,255,0)">(0 ... -9).by(-1) and (0 ..<<span></span> -10).by(-1)</span></font><br><br>On Wednesday, 6 April 2016, Dave Abrahams via swift-evolution <<a href="mailto:swift-evolution@swift.org" target="_blank">swift-evolution@swift.org</a>> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><br>
on Tue Apr 05 2016, Xiaodi Wu <<a href="http://xiaodi.wu-AT-gmail.com" target="_blank">xiaodi.wu-AT-gmail.com</a>> wrote:<br>
<br>
> On Mon, Apr 4, 2016 at 1:22 PM, Dave Abrahams <<a>dabrahams@apple.com</a>> wrote:<br>
>><br>
>> on Sat Apr 02 2016, Xiaodi Wu <<a href="http://xiaodi.wu-AT-gmail.com" target="_blank">xiaodi.wu-AT-gmail.com</a>> wrote:<br>
>><br>
>>> [snip]<br>
>>><br>
>>> Not included:<br>
>>> 1. I know Ranges are in flux, so I've held off on extending Range with<br>
>>> a striding(by:) method in this proof-of-concept.<br>
>><br>
>> They're not in flux, except for not having been reviewed yet; they are<br>
>> settled in the swift-3-indexing-model branch.<br>
><br>
> Did not know that. Will have to study what's there in more detail.<br>
><br>
>>> 2. No attempt at the suggested stride(from:to:steps:) quite yet.<br>
>><br>
>> #1 and #2 are mutually exclusive; we prefer #1 as it removes questions<br>
>> about the meaning of "to" or "through."<br>
><br>
> I wasn't aware that was the thinking. Limiting strides to<br>
> `striding(by:)` removes the ability to express `stride(from: 0, to:<br>
> -10, by: -1)`<br>
<br>
IMO this:<br>
<br>
(-9...0).reverse()<br>
<br>
is better than<br>
<br>
stride(from: 0, to: -10, by: -1)<br>
<br>
What do you think?<br>
<br>
--<br>
Dave<br></blockquote><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
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</blockquote><br><br>-- <br>-- Howard.<br>
</blockquote></div>