From: Christian Neukirchen <chneukirchen@...>
Date: 2005-05-29T18:50:48+09:00
Subject: Re: Useless hack of the saturday morning

gabriele renzi <surrender_it@remove-yahoo.it> writes:

> Hi gurus and nubys,
>
> this morning I stumbled across the Autrijus Tang journal[1],
> which was showing this nifty piece of code:
>
>
> say [~] (-> @c is copy {gather {
> while @c[0] { for @c ->
> {take(.shift)} } }
> }(['Joec','utrk','shle','te6r',' r .','a h.','nPa.'].map:{[split "",$_]}));
>
> in perl6 the [<something>] is the reduce metaoperator, and -> is the
> equivalent of "proc".
> The hard thing was understanding what gather/take are supposed to do.
> A little investigation yielded explanation[2], they seem to be some
> kind of accumulating construct a-la inject. In the tradition of the
> perl6->ruby port such as junctions, .= operator and so on I tried
> implement it.

That's very nice and useful (I often wished for it), but goo already
had it for a long time. :-) It is called "packing" there, see
http://people.csail.mit.edu/jrb/goo/manual.46/goomanual_29.html

I think the implementation with instance_eval can be a bit surprising,
maybe [Dynamic Variables][1] could do that better.

[1]: http://chneukirchen.org/blog/archive/2005/04/dynamic-variables-in-ruby.html

-- 
Christian Neukirchen  <chneukirchen@gmail.com>  http://chneukirchen.org