--- Buddha Buck <[EMAIL PROTECTED]> wrote:
> I think that if there were a slice-based form of grep, it would most
> likely look like you are indexing by a subroutine (or method)
> reference
> that takes no arguments other than an element of the array.
> Something like:
>
> @a = @grades[{$^x > 90}];
>
> or
>
> @a = @grades[-> x { $x > 90}];
>
> or
>
> my StudentGrade @grades;
>
> @a = @grades[.isPassing];
>
> I could see that as being useful.
>
> Of potentially more use would be:
>
> %grades = { Tom => 85, Mary => 95 };
> %a_students = %grades{-> $name, $grade { $grade > 90 } };
> print keys %a_students; # 'Mary'
This is what makes designing an OODB so much fun.
for keys %minima -> $gr
{
@grades{ $gr } = grep { .getGrade() >= $minima[$gr] }, @class;
}
This kind of searching is too easy in a transparent language like SQL,
"SELECT * FROM class WHERE curr_grade >= %min", but it's miserable when
you have to "honor the objects".
Being able to say something like:
@grades{ $gr } = @class «st» {.getGrade() >= $minima[$gr]};
makes for a decent start. Combining vectorizing with objects can help
us build a more intuitive way to talk about operations over
collections.
Which kind of suggests that that idea of a standardized Collections
interface isn't so unreasonable, after all -- I think there's value in
being able to invoke map or grep or zip, etc., on an arbitrary
collector (array, hash, lol, <stream>) and have it work in a
consistent, predictable manner.
(But this kind of thing can be a module, or be an extension, so long as
the core collection types aren't blatantly incompatible.)
(«st» is, of course, the vectorized "such that" operator (aka grep). I
shan't demand a single-character punctuation operator... :0)
=Austin
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