Creating consructor new with empty $self

vit has asked for the wisdom of the Perl Monks concerning the following question:

Replies are listed 'Best First'.
Re: Creating consructor new with empty $self by jethro (Monsignor) on Oct 27, 2010 at 17:27 UTC
Does it make sense? Yes, for example for a shopping cart object, shopping carts usually start empty.	[reply]
Re: Creating consructor new with empty $self by Corion (Patriarch) on Oct 27, 2010 at 16:56 UTC
What happened when you tried?	[reply]
Re^2: Creating consructor new with empty $self by vit (Friar) on Oct 27, 2010 at 17:49 UTC
Nothing happened. So $self will be just an empty hash reference?	[reply]
Re: Creating consructor new with empty $self by sundialsvc4 (Abbot) on Oct 27, 2010 at 18:46 UTC
This notion doesn’t make any sense to me. Anytime you use the `classname -> method` syntax, the first parameter to `method` will always be `classname`. And, the constructor (`new`) must always initialize and return a blessed object-instance. It is perfectly okay for the “blessed object” to be made from an empty-hash. You do not have to have any instance-variables.
Re: Creating consructor new with empty $self by Anonymous Monk on Oct 27, 2010 at 20:07 UTC
Your object doesn't have to be a hash reference, much less contain elements.	[reply]
Re: Creating consructor new with empty $self by pajout (Curate) on Oct 27, 2010 at 17:48 UTC
I think it makes sense. For instance, consider your constructor and following getter/setter method: `sub temperature { my ($self, $t) = @_; if (1 < @_) { $$self{temperature} = $t; } return $$self{temperature}; }` [download] -> I do not see any technical reason for initial filling. Of course, sometimes you really want to initialize it because application logic.	[reply] [d/l]
Re: Creating consructor new with empty $self by Arunbear (Prior) on Oct 27, 2010 at 17:32 UTC
What is the purpose of these objects? That should give an idea of what attributes might be needed.	[reply]


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