On Thu, Jan 24, 2002 at 05:28:59PM -0500, Mark Mills wrote:
> [% IF array.defined %] should tell you if something is null or non-existant in the
>stashhash.
Yep, if 'array' is defined then .defined returns true, even if it's a
reference to an empty array or empty hash.
> As people have said, DWIM sez [% IF array %] should be true only if array contains
>something more than nothing.
As far as I know, there's no way to do this without re-writing large parts
of TT. Even then, I don't think it's possible.
The Perl code generated for
[% IF array %]
looks like
if ($stash->get('array'))
It has to work that way so that things like this:
[% array1 = array2 %]
properly translate to
$stash->set('array1', $stash->get('array2'));
That is, it's no good having $stash->get('array2') realised that 'array2'
is an array reference (it can do that fine) and then return 0 or 1 depending
on whether or not it contains anything. If you did that, then you'd get
this:
[% array1 = [] %]
[% array2 = array1 %] # array2 = 0
Perhaps the best solution is to have a '.size' method which works consistently
across all data types:
[% item.size %] # 1
[% hash.size %] # scalar(keys %$hash)
[% list.size %] # scalar(@$list)
It's not as DWIMmy as [% IF something %], but at least you could then be
sure that [% IF something.size %] will always work as expected.
If you look for the precedent in Perl, you have something like:
my $ref = [ ];
if ($ref) {
# TRUE!
}
You have to think of a list ref as being a container like can of beans.
Although it tempting to think that the DWIMery might be nice, I think
the correct interpretation of 'if $can_of_beans' is to test if the container
is defined, not if it contains any beans.
A
