2009/4/20 Chas. Owens <chas.ow...@gmail.com>:
> On Mon, Apr 20, 2009 at 11:21, Dermot <paik...@googlemail.com> wrote:
...
>> I thought that I could say somethign
>> like, "if %defaults, return %defaults else populate %defaults and
>> return".
>>
>> Here's the error I am getting:
>>
>> Can't modify private hash in logical or assignment (||=) at
>> /export/web/lib/Foo.pm line 28, near "}
> snip
>
> You should have gone with your first instinct:
>
> sub getDefaults {
>
> return if %defaults;
>
>
> my $sql = q{SELECT * from bar};
> my $sth = $dbh->prepare($sql);
> $sth->execute;
> while (my $row = fetchrow_hashref) {
> $defaults{$row->{id}} = $row->{'description'};
> }
> return
> }
Just so I'm clear because it's actually quite a hard thing to test, my
sub should look start like this:
my %defaults # Declared globally;
sub getDefaults {
return if %defaults;
%defaults = do {...}
}
> You might also want to look into the Singleton pattern[1].
>
> 1. http://en.wikipedia.org/wiki/Singleton_pattern
Design patterns. I have come across this term a few times but there is
very little Perl examples of Design Patterns around and not a single
example of Singleton pattern on that page :-(
Thanx Chas,
Dp.
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