Michael Lazzaro wrote:
2a) When a cell is explicitly re-undefined, does the default value take
effect?
my @a is Array( default => 'foo' ) = (1,2,3);
@a[1] = undef;
@a[1]; # undef, or 'foo'?
STRAWMAN ANSWER: 'foo'.
If C<undef> is a valid value for a cell, then I should be able to store
it. I think that C<delete> would better convey the intent -- it would
also help with the behavior of negative indexes.
2b) Primitive-typed arrays: Given the behavior of (2a), and the fact
that primitive-typed arrays can't store undef, what happens here?
my int @a is Array( default => 5 );
@a[0] = 0;
@a[0]; # 0, or 5?
Definitely 0. Definitely 0. DEFINITELY ZERO.
@a[0] = undef;
@a[0]; # 0, or 5?
STRAWMAN ANSWER: 5, in both cases. So don't do that unless you mean
it.
0: see (2a)
3) Can the default value be a closure, based on index location?
my @a is Array( default => { $_ ** 2 });
STRAWMAN ANSWER: Yes, because it's cool.
sounds good. But we wqant to ensure that the default value can actually
be a closure -- i.e. its not a C<default> if we execute it.
3a) NOTE that closure-based defaults effectively render the array
infinite. Therefore -- If the requested index is negative, what happens?
@a[-5];
STRAWMAN ANSWER: The closure just gets a negative number as the
requested index.
It's up to you to make it work, if you want it to.
Yes
3b) Does an "infinite" array still get an exception thrown when trying
to access an infinite [Inf] or [-Inf] index?
STRAWMAN ANSWER: Yes, it does.
Should follow (3a): the generator can through the exception if desired.
Now, what about @a[2.5]: can my generator do interpolation?
Dave.
--
http://dave.whipp.name
