Improving std.range.Zip

[Philippe Sigaud]

2010/10/24 Tomek Sowiński <just at ask.me>:
> I have noticed an emerging idiom in my code lately: bring together n ranges,
> transform them to one range using a n-ary function. Currently it's achieved
> with:
>
> map!((a) {return myNaryFun(a._0, a._1, ...); })(zip(range1, range2, ...));
>
> It's a bit of a nuisanse -- rarely do my transforming functions take tuples,
> and there's the necessity of composing 2 higher-order ranges to render
> fairly common functionality. I think Zip could be further parametrized with
> a zipper function, so that the above code would boil down to:
>
> zip!myNaryFun(range1, range2, ...);
>
> Having looked at Zip's source, such change shouldn't be a big deal. Oh, and
> the default zipper function would be std.typecons.tuple, not to trouble
> those not keen on generalization.

That's what Haskell calls ZipWith. I called it tmap (as in tuple-map)
when I needed it in D.
IMHO, it should be a generalization of std.algorithm.map: let it
accept n ranges and a n-ary function. It can even do a partial check
at compile-time.
Extending filter() and reduce() to work with n ranges in parallel and
a n-args function is also useful.

you may be interested in looking there:

http://www.dsource.org/projects/dranges/

(more specifically, in the algorithm module)

Philippe