in reply to OO problems

Perhaps I dont understand what you are doing, but this might be what you want:
my $foo = new Foo;

$foo->add_item("Cheese");
$foo->add_item("Mice");
$foo->add_item("Rat", "Cat");

use Data::Dumper;
print Data::Dumper->Dump([$foo], ['foo']);

package Foo;

sub new {
    bless { _orderid => '', _items => [] }, $_[0];
}

sub add_item {
    push @{ $_[0]->{_items} }, @_[1 .. $#_];
}

[download]
Results
$foo = bless( {
                '_orderid' => '',
                '_items' => [
                              'Cheese',
                              'Mice',
                              'Rat',
                              'Cat'
                            ]
              }, 'Foo' );

[download]

Replies are listed 'Best First'.
RE: Re: OO problems
by steveAZ98 (Monk) on Jul 24, 2000 at 02:20 UTC
    Yeah, that's pretty much what I'm doing, and it works when I do it like that. I tried writing a minimal example to get the error and the code works. I'll have to re-examine my code, must be something wrong going on in there.
    Thanks
    One more note. Is it legal to tie a hash using Apache::Session and then bless that hash into an object. This is what I'm doing and maybe that is the cause of my problem? 
    sub new {
    my $class = shift;
    my ($id)  = shift;
    my $hr    = {};
    tie %{$hr}, 'Apache::Session::MySQL', $id {
       etc...
    };
    my $self = bless $hr,$class;
    return $self;
}

    [download]
[reply]
[d/l]
      According to Damian Conway (master of most things related to bless and a whole lot of things that aren't), it's legal to bless a tied hash into an object.

      However, your method doesn't look quite right. You create an anonymous hash, assign its reference to a scalar, and then dereference and bless it. In theory, that should work, but you'll have to do two layers of indirection when trying to get at the tied hash. I think something like the following is more in line with what you want. (Disclaimer: I haven't tried this, and I've never used Apache::Session, but it's a little cleaner.) 

      sub new {
    my $class = shift;
    my $id = shift;
    my %h = ();
    tie %h, 'Apache::Session::MySQL', $id {
        # whatever goes here
    };
    return bless(\%h, $class);
}

      [download]
[reply]
[d/l]
        Thanks, I see what your saying as far as that code goes. It actually acts the same way, but is probably better the way you wrote it.
        I've written a smaller version for debugging and it seems that the problem is in getting Apache::Session to store the lower level data structures before the object goes away. I timestamp it on creation and in DESTROY before I untie it, but it still isn't working for me.
        I'll keep playing and let you know if I figure anything out. It seems to me to be a error on my part of the implementation of Apache::Session, I just have to figure out what it is! :)
        Thanks Again.
[reply]
        I discovered my problem was in calling new() on an object that already existed in the tied hash and thus overwrote the stored information. I fixed it with the following very simple code. Damn I've been banging my head over this one. Feel so stupid! :) 

        sub set_items { $_[0]->{_items} = $_[0]->{_items} || Order->new() }

        [download]
        Thanks again everyone!

[reply]
[d/l]

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