Hi: On 01 Dec 2010, at 01:31, presid...@basnetworks.net wrote:
>>> That is true for PHP variables. isset is basically saying "does this >>> variable exist", and unset is saying to get rid of it. >> >> This is also true for object properties - see magic methods. I don't see >> why you shouldn't be able to unset them - you can do that with regular >> properties... So what you imagine would happen if you call >> unset($foo->property) or isset($foo->property)? > > Its not a matter of consistency - Properties, as a cross-language concept > are not meant to work that way. I tend to disagree. The need to be consistent inside of PHP has precedence over being consistent with other languages. > You need to think of a property as a set > of two methods that just have a pretty syntax. Methods cannot be unset, > and nor should properties be allowed to. isset() should simply tell us > whether a property with the specified name is part of the class or not. I think, it really is the other way around. Properties are meant to give the programmer the illusion that she is just having a field. That is abstraction. She does not care about implementation details. And that is the power of properties. isset() and unset() are perfectly fine in that context. And I do not see a problem to provide the standard semantics for them automatically, and let the programmer add isset/unset methods to the property as needed in exactly the same style as get/set. There is a good usecase for asking whether a property has been set, for instance to verify initialization. And, of course unset has also a useful meaning. It is about the value, and even so there are methods around a value, properties are meant to be values. There are definitely use-cases where that does not hold, but that is application specific. > isset() in the way you suggest would just be confusing. It would allow is > to say that a property does not exist, when in fact it does exist. This > is not logical. From the docu: isset — Determine if a variable is set and is not NULL There is nothing confusing about isset($this->Hours) == FALSE in your example if isset($this->seconds) == FALSE. Best regards Stefan -- Stefan Marr Software Languages Lab Vrije Universiteit Brussel Pleinlaan 2 / B-1050 Brussels / Belgium http://soft.vub.ac.be/~smarr Phone: +32 2 629 2974 Fax: +32 2 629 3525 -- PHP Internals - PHP Runtime Development Mailing List To unsubscribe, visit: http://www.php.net/unsub.php
