Hi,
here's one that I have no idea how to go about:
Take this Perl code:
my $i = iterator([1 .. 3]);
while (defined (my $val = $i->()) {
print $val, "\n";
}
__END__
1
2
3
I am now trying to implement iterator() as XSUB so its job is to return
a closure (closing over iterator's argument). Ideally, the function
reference it returns should also be implemented as XSUB.
My idea was to get the CV* of the iterator to be returned, maybe thusly:
CV *closure = get_cv("_iterator", FALSE);
...
XSRETURN(sv_2mortal(newSVrv_noinc((SV*)closure)));
A CV has a padlist so I thought I could simply abuse closure's padlist
to store the array-ref passed to iterator(). And then, each time this
iterator is triggered, the XSUB implementing it can access its own
padlist and shift a value from the array-ref stored inside.
So far I don't know whether the above is even theoretically feasible. I
notice that CvPADLIST(closure) is null which is probably a bad sign. And
then I have no idea how an XSUB could access its own padlist. It's not
in PL_curpad as it looks.
Or does someone know how to do this properly? The sketched outline above
looks quick-and-dirty-ish (not evenin mentioning that does't yet work).
Cheers,
Tassilo
--
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