On Thu, 14 Nov 2002, Luke Palmer wrote:
> > nest:
> > Nest is the power loop thingy documented in Raphael Finkel's top notch
> > book "Advanced Programming Language Design", near the end of the "Control
> > Structures" chapter -- this book is in PDF format:
> > http://www.nondot.org/sabre/Mirrored/AdvProgLangDesign/
>
> The only thing it doesn't cover is C<nest>, which, in practical
> situations, isn't all that useful anyway. It's cleaner just to nest
> manually.
In 2002, I said:
As the Finkel book points out, that only works if you know ahead of
time how many layers deep you're going to be nesting. Personally, I don't
expect to need nest more than once or twice in my life, but it'd be useful for
the times it's needed.
Now I add:
I knew there was a situation where these are useful, and I've found
it, and it'll probably be more frequent in Perl6 than Perl5: recursing through
multidimensional arrays where you don't know how many dimensions there are.
For example, nest would be great for implementing some of the APL operators.
Just fors the record:
Perl APL
Operators Functions
Hyper-operators Operators
http://www.info.univ-angers.fr/pub/gh/wAides/sax6_userdoc.pdf
Look under Language Guide/Operators.
:)
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| Name: Tim Nelson | Because the Creator is, |
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