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Re: Object constructors/destructors

From Jerry Stuckle <jstucklex@attglobal.net>
Newsgroups comp.lang.php
Subject Re: Object constructors/destructors
Date 2014-02-26 16:01 -0500
Organization A noiseless patient Spider
Message-ID <lelkn9$919$1@dont-email.me> (permalink)
References (17 earlier) <530d1140$0$9522$9b4e6d93@newsspool1.arcor-online.net> <lej3sh$gmp$1@dont-email.me> <lej8ji$e3a$1@dont-email.me> <lejife$v6d$2@dont-email.me> <530e4a38$0$9520$9b4e6d93@newsspool1.arcor-online.net>

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On 2/26/2014 3:10 PM, Christoph Michael Becker wrote:
> Jerry Stuckle wrote:
>
>> On 2/25/2014 6:22 PM, Adam Harvey wrote:
>>> On Tue, 25 Feb 2014 17:01:52 -0500, Jerry Stuckle wrote:
>>>> On 2/25/2014 4:55 PM, Christoph Michael Becker wrote:
>>>>> I firmly believe that it wouldn't make sense to call a (user-defined)
>>>>> constructor when unserializing or cloning an object.  A constructor
>>>>> usually serves to initialize an object -- what already had happened in
>>>>> both cases.
>>>>>
>>>>>
>>>> It makes perfect sense.  Not everything is necessarily valid in the new
>>>> object.  For instance, a logging object may require opening the log
>>>> file.  There are many instances where a resource is no longer available
>>>> and needs to be recreated.
>>>
>>> Indeed, which is why PHP provides the Serializable interface (and, for BC
>>> reasons, also __sleep and __wakeup) to allow those sorts of
>>> reinitialisation tasks.
>>>
>>> I agree with Christoph: since the object is already instantiated, it
>>> doesn't logically make sense to call the constructor once again.
>>>
>>
>> But the object is NOT instantiated.  It was at one time, then destroyed.
>>   When the new script starts, there is no object in existence.
>>
>>>>> Jerry Stuckle wrote:
>>>>>> I know of no other OO language which would allow this.
>>>>>
>>>>> Others may.
>>>>>
>>>>>
>>>> None that I know of.  Please name one.
>>>
>>> Python's pickle operates the same way:
>>> http://docs.python.org/2/library/pickle.html#object.__getinitargs__
>>>
>>> Providing a way to instantiate objects without calling the constructor
>>> does have valid uses (mostly for testing), which is why PHP 5.4 and later
>>> versions also provide a way to do so via reflection (avoiding the
>>> unserialize() hack):
>>> http://php.net/reflectionclass.newinstancewithoutconstructor
>>>
>>> Adam
>>>
>>
>> Not knowing Python, I can't say.  But if it is a true object, then they
>> are also violating OO principles.
>>
>> OO demands creation of a new object requires a constructor call.
>> Period.
>
> Do you understand, what's the purpose of a constructor?  It is there to
> *initialize* an instance.  If there is nothing to initialize, it is not
> strictly necessary to call any constructor.
>

Yes, I understand the purpose of a constructor - it looks like much more 
than you do.

> But anyway, unserializing an object is *not* creating a new object.
> Consider a class man.  When a new object is instantiated the constructor
> is called to initialize the person with respective properties (e.g. age
> = 0).  Later this man goes to sleep (serialize); after he wakes up
> (unserialize) the constructor is not called again, as this would reset
> the man to his initial properties, and surely after a good night of
> sleep one may feel younger, but the age has not been reset.
>

It is creating a new object.  Before unserialize(), the object does not 
exist - only a bunch of data.   And that data is NOT an object!  You 
cannot call an object method on the data, for instance.  It is no 
different than if the data were stored in a file and loaded in Java or 
C++, for instance.  To create the object requires a call to a constructor.

>>           If you think otherwise, I suggest you learn more about how OO
>> is supposed to work.  PHP is not a good example.
>
> I refrain from commenting this statement.
>

If you think otherwise, I suggest you learn more about how OO is 
supposed to work.  PHP is not a good example.

-- 
==================
Remove the "x" from my email address
Jerry Stuckle
jstucklex@attglobal.net
==================

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Thread

Operator precedence Christoph Michael Becker <cmbecker69@arcor.de> - 2014-02-23 18:03 +0100
  Re: Operator precedence GS <nomail@nospam.org.invalid> - 2014-02-23 19:42 +0000
    Re: Operator precedence Christoph Michael Becker <cmbecker69@arcor.de> - 2014-02-23 21:23 +0100
    Re: Operator precedence Jerry Stuckle <jstucklex@attglobal.net> - 2014-02-23 16:34 -0500
      Re: Operator precedence Richard Damon <Richard@Damon-Family.org> - 2014-02-23 18:36 -0500
        Re: Operator precedence Jerry Stuckle <jstucklex@attglobal.net> - 2014-02-23 21:09 -0500
          Re: Operator precedence Ben Bacarisse <ben.usenet@bsb.me.uk> - 2014-02-24 04:49 +0000
            Re: Operator precedence Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-02-24 12:56 +0100
              Re: Operator precedence Christoph Michael Becker <cmbecker69@arcor.de> - 2014-02-24 17:38 +0100
              Re: Operator precedence Ben Bacarisse <ben.usenet@bsb.me.uk> - 2014-02-24 21:25 +0000
                Re: Operator precedence Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-02-25 00:38 +0100
                Re: Operator precedence Christoph Michael Becker <cmbecker69@arcor.de> - 2014-02-25 01:07 +0100
                Re: Operator precedence Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-02-25 01:37 +0100
                Re: Operator precedence Christoph Michael Becker <cmbecker69@arcor.de> - 2014-02-25 02:12 +0100
                Re: Operator precedence Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-02-25 03:29 +0100
                Re: Operator precedence Christoph Michael Becker <cmbecker69@arcor.de> - 2014-02-25 19:41 +0100
                Re: Operator precedence Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-02-25 19:55 +0100
                Re: Operator precedence Christoph Michael Becker <cmbecker69@arcor.de> - 2014-02-25 21:36 +0100
                Re: Operator precedence Ben Bacarisse <ben.usenet@bsb.me.uk> - 2014-02-25 03:08 +0000
                Re: Operator precedence Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-02-25 04:17 +0100
                Re: Operator precedence Ben Bacarisse <ben.usenet@bsb.me.uk> - 2014-02-25 04:45 +0000
                Re: Operator precedence GS <nomail@nospam.org.invalid> - 2014-02-25 21:45 +0000
            Re: Operator precedence Jerry Stuckle <jstucklex@attglobal.net> - 2014-02-24 07:00 -0500
              Re: Operator precedence Christoph Michael Becker <cmbecker69@arcor.de> - 2014-02-24 18:11 +0100
                Re: Operator precedence Jerry Stuckle <jstucklex@attglobal.net> - 2014-02-24 14:27 -0500
                Re: Operator precedence Christoph Michael Becker <cmbecker69@arcor.de> - 2014-02-25 01:25 +0100
                Re: Operator precedence Jerry Stuckle <jstucklex@attglobal.net> - 2014-02-24 20:40 -0500
              Re: Operator precedence Ben Bacarisse <ben.usenet@bsb.me.uk> - 2014-02-24 21:23 +0000
                Re: Operator precedence Jerry Stuckle <jstucklex@attglobal.net> - 2014-02-24 16:45 -0500
                Re: Operator precedence Ben Bacarisse <ben.usenet@bsb.me.uk> - 2014-02-25 04:32 +0000
                Re: Operator precedence Jerry Stuckle <jstucklex@attglobal.net> - 2014-02-24 23:47 -0500
                Re: Operator precedence Ben Bacarisse <ben.usenet@bsb.me.uk> - 2014-02-25 16:56 +0000
                Re: Operator precedence Jerry Stuckle <jstucklex@attglobal.net> - 2014-02-25 13:59 -0500
                Re: Operator precedence Christoph Michael Becker <cmbecker69@arcor.de> - 2014-02-25 20:19 +0100
                Re: Operator precedence Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-02-25 20:43 +0100
                Re: Operator precedence Jerry Stuckle <jstucklex@attglobal.net> - 2014-02-25 16:02 -0500
                Re: Operator precedence Jerry Stuckle <jstucklex@attglobal.net> - 2014-02-25 16:01 -0500
                Object constructors/destructors (was: Operator precedence) Christoph Michael Becker <cmbecker69@arcor.de> - 2014-02-25 22:19 +0100
                Re: Object constructors/destructors Jerry Stuckle <jstucklex@attglobal.net> - 2014-02-25 16:32 -0500
                Re: Object constructors/destructors Christoph Michael Becker <cmbecker69@arcor.de> - 2014-02-25 22:55 +0100
                Re: Object constructors/destructors Jerry Stuckle <jstucklex@attglobal.net> - 2014-02-25 17:01 -0500
                Re: Object constructors/destructors Adam Harvey <usenet@adamharvey.name> - 2014-02-25 23:22 +0000
                Re: Object constructors/destructors Jerry Stuckle <jstucklex@attglobal.net> - 2014-02-25 21:10 -0500
                Re: Object constructors/destructors Christoph Michael Becker <cmbecker69@arcor.de> - 2014-02-26 21:10 +0100
                Re: Object constructors/destructors Jerry Stuckle <jstucklex@attglobal.net> - 2014-02-26 16:01 -0500
                Re: Object constructors/destructors Christoph Michael Becker <cmbecker69@arcor.de> - 2014-02-26 22:59 +0100
                Re: Object constructors/destructors Jerry Stuckle <jstucklex@attglobal.net> - 2014-02-26 17:19 -0500
                Re: Object constructors/destructors Christoph Michael Becker <cmbecker69@arcor.de> - 2014-02-26 23:39 +0100
                Re: Object constructors/destructors Jerry Stuckle <jstucklex@attglobal.net> - 2014-02-26 22:30 -0500
                Re: Object constructors/destructors Christoph Michael Becker <cmbecker69@arcor.de> - 2014-02-27 18:28 +0100
                Re: Object constructors/destructors Jerry Stuckle <jstucklex@attglobal.net> - 2014-02-27 16:09 -0500
                Re: Object constructors/destructors Christoph Michael Becker <cmbecker69@arcor.de> - 2014-02-28 14:52 +0100
                Re: Object constructors/destructors Jerry Stuckle <jstucklex@attglobal.net> - 2014-02-28 09:08 -0500
                Re: Object constructors/destructors Christoph Michael Becker <cmbecker69@arcor.de> - 2014-02-28 16:52 +0100
                Re: Object constructors/destructors Jerry Stuckle <jstucklex@attglobal.net> - 2014-02-28 11:03 -0500
                Re: Object constructors/destructors Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-02-27 01:00 +0100
                Re: Object constructors/destructors Jerry Stuckle <jstucklex@attglobal.net> - 2014-02-26 22:39 -0500
                Re: Object constructors/destructors Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-02-27 18:29 +0100
                Re: Object constructors/destructors Jerry Stuckle <jstucklex@attglobal.net> - 2014-02-27 16:14 -0500
                Re: Object constructors/destructors Christoph Michael Becker <cmbecker69@arcor.de> - 2014-02-26 00:18 +0100
                Re: Object constructors/destructors Jerry Stuckle <jstucklex@attglobal.net> - 2014-02-25 21:08 -0500
                Re: Object constructors/destructors Richard Damon <Richard@Damon-Family.org> - 2014-02-26 07:50 -0500
                Re: Object constructors/destructors Jerry Stuckle <jstucklex@attglobal.net> - 2014-02-26 08:44 -0500
                Re: Object constructors/destructors Richard Damon <Richard@Damon-Family.org> - 2014-02-26 23:49 -0500
                Re: Object constructors/destructors Jerry Stuckle <jstucklex@attglobal.net> - 2014-02-27 08:25 -0500
                Re: Object constructors/destructors Richard Damon <Richard@Damon-Family.org> - 2014-03-01 12:56 -0500
                Re: Object constructors/destructors Jerry Stuckle <jstucklex@attglobal.net> - 2014-03-01 14:22 -0500
                Re: Object constructors/destructors Richard Damon <Richard@Damon-Family.org> - 2014-03-02 14:28 -0500
                Re: Object constructors/destructors Jerry Stuckle <jstucklex@attglobal.net> - 2014-03-02 15:42 -0500
                Re: Object constructors/destructors Richard Damon <Richard@Damon-Family.org> - 2014-03-02 17:14 -0500
                Re: Object constructors/destructors Jerry Stuckle <jstucklex@attglobal.net> - 2014-03-02 17:48 -0500
                Re: Object constructors/destructors Tim Streater <timstreater@greenbee.net> - 2014-03-02 23:05 +0000
                Re: Operator precedence Ben Bacarisse <ben.usenet@bsb.me.uk> - 2014-02-25 21:08 +0000
                Re: Operator precedence Christoph Michael Becker <cmbecker69@arcor.de> - 2014-02-25 22:29 +0100
                Re: Operator precedence Ben Bacarisse <ben.usenet@bsb.me.uk> - 2014-02-25 23:15 +0000
              Re: Operator precedence Richard Damon <Richard@Damon-Family.org> - 2014-02-24 22:41 -0500
                Re: Operator precedence Jerry Stuckle <jstucklex@attglobal.net> - 2014-02-24 23:59 -0500
                Re: Operator precedence Richard Damon <Richard@Damon-Family.org> - 2014-03-01 13:39 -0500
                Re: Operator precedence Jerry Stuckle <jstucklex@attglobal.net> - 2014-03-01 14:29 -0500
                Re: Operator precedence Richard Damon <Richard@Damon-Family.org> - 2014-03-02 15:22 -0500
                Re: Operator precedence Jerry Stuckle <jstucklex@attglobal.net> - 2014-03-02 15:49 -0500
                Re: Operator precedence Christoph Michael Becker <cmbecker69@arcor.de> - 2014-02-25 19:15 +0100
  Re: Operator precedence Ben Bacarisse <ben.usenet@bsb.me.uk> - 2014-02-23 20:56 +0000
    Re: Operator precedence Christoph Michael Becker <cmbecker69@arcor.de> - 2014-02-24 14:28 +0100

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