ch-ch-changes

[Bill Baxter]

On Wed, Jan 28, 2009 at 2:01 PM, Jarrett Billingsley
<jarrett.billingsley at gmail.com> wrote:
> On Tue, Jan 27, 2009 at 11:15 PM, Andrei Alexandrescu
> <SeeWebsiteForEmail at erdani.org> wrote:
>> I've worked valiantly on defining the range infrastructure and making
>> std.algorithm work with it. I have to say that I'm even more pleased with
>> the result than I'd ever expected when I started. Ranges and concepts really
>> make for beautiful code, and I am sure pretty darn efficient too.
>>
>> There's a lot to sink one's teeth in, but unfortunately the code hinges on a
>> compiler fix that Walter was kind enough to send me privately. I did
>> document the work, but the documentation doesn't really make justice to the
>> extraordinary possibilities that lay ahead of us. Anyhow, here's a sneak
>> preview into the up-and-coming ranges and their algorithms.
>>
>> http://ssli.ee.washington.edu/~aalexand/d/web/phobos/std_range.html
>> http://ssli.ee.washington.edu/~aalexand/d/web/phobos/std_algorithm.html
>>
>> Ranges are easy to define and compose efficiently. It was, however, a pig to
>> get a zip(r1, r2, ...) working that can mutate back the ranges it iterates
>> on. With that, it's very easy to e.g. sort multiple arrays in parallel.
>> Similarly, chain(r1, r2, ...) is able to offer e.g. random iteration if all
>> components offer it, which means that you can do crazy things like sorting
>> data that sits partially in one array and partially in another.
>>
>> Singly-linked list ranges are in, and to my soothing I found an answer to
>> the container/range dichotomy in the form of a topology policy. A range may
>> or may not be able to modify the topology of the data it's iterating over;
>> if it can, it's a free-standing range, much like built-in arrays are. If it
>> can't, it's a limited range tied to a container (of which I defined none so
>> far, but give me time) and it's only the container that can mess with the
>> topology in controlled ways. More on that later.
>>
>> Feedback welcome.
>
> This is some awesome stuff.  std.range and std.algorithm are really
> coming together into a compelling whole.  I don't know what else to
> say - _you_ seem to know what you're doing!

Indeed.  It makes me wish the porting fairy would visit my D1 code
repositories tonight while I sleep.

> Also - "toe" is still a stupid name.  ;)  "first" and "last" would
> have been my first choices, they seem so obvious.

It's especially strange given the description:
"toe -- returns the rightmost element"
I don't usually think of my toes as being my rightmost element...

What is the argument against "first" and "last", anyway?  Just that
they're boring?

--bb