On Mon, Mar 26, 2001 at 10:50:09AM -0500, Uri Guttman wrote:
> SC> it? That is, @s = sort { f($a) <=> f($b) } @t
>
> because that would require the PSI::ESP module which isn't working
> yet. how would perl intuit exactly the relationship between the records
> and the keys extraction and comparison? the ST defines that by the first
> map and the comparison callback. just providing the comparison would
> entail perl parsing an arbitrarily complex piece of code and then
> autognerating the map that would produce an anon array that fits it. not
> a simple task.
No, it wouldn't, don't be silly. The ST can always be generalized to
ST(data, func, compare) =
map { $_->[0] } sort { compare($a->[1], $b->[1]) } map { [$_, f($_)] } data
In fact, you can implement it in LISP just like that:
(defun Schwartzian (list func compare)
(mapcar
(lambda (x) (car x))
(sort
(mapcar
(lambda (x) (cons x (funcall func x)))
list
)
(lambda (x y) (funcall compare (cdr x) (cdr y)))
)
)
)
Do you see any ESP there? Do you see any parsing of arbitrary pieces of
code? No, me neither.
--
SM is fun. ADSM is not.
"Safe, Sane, Consensual"... three words that cannot used to describe
ADSM.
- Graham Reed, sdm.
