Re: RFC: C-sharp style property get/set syntax for PHP
| From: | Richard Quadling | Date: | Mon, 06 Dec 2010 11:12:19 +0000 |
| Subject: | Re: RFC: C-sharp style property get/set syntax for PHP | ||
| References: | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 | Groups: | php.internals |
| Request: | Send a blank email to internals+get-50871@lists.php.net to get a copy of this message | ||
On 5 December 2010 16:47, <president@basnetworks.net> wrote:
> If I have an object called "PiggyBank", with the property "dollars" set to
> 5, "dimes" set to 4 and "nickles" set to 1, then I get the contents of the
> property "Total", I can predict it will give me the value 5.45. That is
> what properties are really for.
To me, the "balance" on my piggy bank is a readonly, dynamic attribute/property.
OK. Piggy bank is too small an entity. My kids' piggy banks have only
1 user per bank. The balance changes rarely 'cause they don't do a lot
of housework. Yet.
But for a larger entity, something with many people altering data via
an "instrument of change" (a term I got from Sage Accounting a long
time ago), then the "balance" on an account will change in unknown
ways.
And a synthetic property like "AvailableBalance" will certainly look
like a random value, whilst orders are taken during the day and
invoices raised and payments allocated. All in real time. A real world
process.
What I'm confused by is what you would consider a property? Why does
predictability matter? Not all properties of an entity are
predictable. My kids have an attribute of "mood". They sure as hell
aren't predictable.
If you have a clock object, the "time" is a readonly, dynamic
property/attribute of a clock. Makes sense?
You would want $clock->time as a property. Not $clock->getTime().
Well. OK. You _COULD_ and it would solve all the issues you have with
dynamic, readonlys, but "time" is a property.
What would you expect to be the natural behaviour of unset($clock->time); ?
If I have to call getTime(), then I've just got setters/getters
(__magic will do). Suddenly time is no longer a property of a clock.
I can see we have very different opinions about the implementation and
the possible use of properties. I'm quite happy with that. Either way,
I think the basic proposal is very good. I've always wanted
setters/getters in PHP specifically to implement readonly/writeonly
attributes when I went from Delphi to PHP. The concept of grouping
these together into a "property" (like C#), rather than having actual
set and get methods (like Delphi) certainly does keep things together.
I think being able to call the getter/setter as part of fluid
interface would be useful. For each property, there would be getxxx,
setxxxx, issetxxxx, unsetxxxx. That may look useful and I think for
those that build classes like ORM systems, then probably of no issue
and would be a major feature. But maybe too much for others not using
that level of technology.
As you can see, I'm not happy with having to keep with a "method" to
update what I would consider a "property" (semantics and all that).
I'm not happy with isset() calling the getter. But I'll adapt. I don't
have the core knowledge or experience to argue much beyond what I've
already said.
The only thing I can think of though is __get can return a seemingly
random value for an undefined property. In keeping with that, why
couldn't a real property? In PHP's terms (not C#), what's the
difference?
Richard.
--
Richard Quadling
Twitter : EE : Zend
@RQuadling : e-e.com/M_248814.html : bit.ly/9O8vFY