[DUG] basic question

[Myles Penlington]

If they did (share the same class var), I would regard that as a bug.
Can't say I've tried though.

Myles.


-----Original Message-----
From: delphi-bounces at delphi.org.nz [mailto:delphi-bounces at delphi.org.nz]
On Behalf Of Neven MacEwan
Sent: Thursday, 26 July 2007 09:16
To: NZ Borland Developers Group - Delphi List
Subject: Re: [DUG] basic question

Dennis Chuah wrote:
>
> As for the use of class methods ... plenty.  Eg., use it to replace 
> unit procedures and functions.  Use it to implement singleton classes 
> and class factories. 

Yes I agree, I've used them for this 'pseudo objectification', Its 
inelegant to use them for singletons since they can't (couldn't!) 
encapsulate the instance

Which leads me to another point, It would be nice (and maybe Delphi 
does) have class variables reintroduced in subclasses ie

TSingleton = class
  public
    class var Instance;
 end;

TSingletonA = class(TSingleton)

)

TSingletonB = class(TSingleton)

)

do a & B 'share' Instance?

Neven


 

> overriden, etc.  The 'self' parameter to class methods is the class 
> reference.  Not as useless as Neven thinks.
>
> ----- Original Message ----- From: "David Moorhouse" 
> <delphi at moorhouse.net.nz>
> To: "NZ Borland Developers Group - Delphi List" <delphi at delphi.org.nz>
> Sent: Wednesday, July 25, 2007 10:15 PM
> Subject: Re: [DUG] basic question
>
>
>> AnInstance := TAnObject.Create;
>>
>> if that's not a class method I'm not sure what is ;)
>>
>> D
>>
>>
>> On Wed, 25 Jul 2007 21:33:25 +1200, you wrote:
>>
>>> Sean
>>>
>>> Thanks, I grovel corrected :-), Still little use with no data, ie 
>>> Data +
>>> Algorithms = Programs
>>>
>>> N
>>>> Class methods have been around for years, explicitly.  As in
>>>> TMyClass.DoSomething, no nil instances required.
>>>>  have just looked it up in my "Using Delphi 3" (pub 1997) book that

>>>> I keep
>>>> lying around for no apparent reason, so it's been at least a
decade.
>>>>
>>>> Class variables etc are newer
>>>>
>>>>
>>>> Regards
>>>>
>>>> Sean
>>>> ---------------------------------------
>>>> Sean Cross
>>>> mailto:sean at sourceitsoftware.com
>>>>
>>>> Pics Print - The photo printing solution for Windows.
>>>> http://www.picsprint.com
>>>>
>>>> Rental Property Manager - Rental management made easy
>>>> http://www.sourceitsoftware.com
>>>>
>>>>
>>>>
>>>>> -----Original Message-----
>>>>> From: delphi-bounces at delphi.org.nz [mailto:delphi-
>>>>> bounces at delphi.org.nz] On Behalf Of Neven MacEwan
>>>>> Sent: Wednesday, 25 July 2007 8:19 p.m.
>>>>> To: NZ Borland Developers Group - Delphi List
>>>>> Subject: Re: [DUG] basic question
>>>>>
>>>>> Dennis
>>>>>
>>>>>> Class methods have been around since Delphi 2.  Where have you
been
>>>>>> all these years?
>>>>>>
>>>>> Not explicitly, as I said, you cannot for example call them on the
>>>>> class, you call them on a nil instance
>>>>> which is hardly elegant php for example you would call a class
method
>>>>> by
>>>>> TClass::Method()
>>>>>
>>>>> To reinforce this, why did they introduce a 'class' keyword if
they
>>>>> were
>>>>> already there?
>>>>>
>>>>> N
>>>>>
>>>>>> Class types, consts and vars came in D2006, I think, or might be
in
>>>>>> D2005.
>>>>>>
>>>>>> ----- Original Message ----- From: "Neven MacEwan"
<neven at mwk.co.nz>
>>>>>> To: "NZ Borland Developers Group - Delphi List"
>>>>>>
>>>>> <delphi at delphi.org.nz>
>>>>>
>>>>>> Sent: Wednesday, July 25, 2007 7:25 PM
>>>>>> Subject: Re: [DUG] basic question
>>>>>>
>>>>>>
>>>>>>
>>>>>>> J
>>>>>>>
>>>>>>> My point is Delphi (generic) does not have Class Methods/Vars or
>>>>>>> are you saying that 'Delphi' only applies to D2005+
>>>>>>>
>>>>>>> As for sarcasm, its a matter of opinion I found his response
smug.
>>>>>>>
>>>>>>> N
>>>>>>>
>>>>>>>
>>>>>>>> I'll answer for Chee Wee (not Chee - common mistake)
>>>>>>>>
>>>>>>>> These articles were by Nick about changes since Delphi 7.
>>>>>>>> http://dn.codegear.com/article/34325 (VCL)
>>>>>>>> http://dn.codegear.com/article/34323 (IDE)
>>>>>>>> http://dn.codegear.com/article/34324 (Language)
>>>>>>>>
>>>>>>>> I don't think his original reply was sarcastic either. Why 
>>>>>>>> would he
>>>>>>>> need to clarify something, you're the one that didn't do any
>>>>>>>>
>>>>> research
>>>>>
>>>>>>>> before saying something. Especially when coming from a version 
>>>>>>>> that
>>>>>>>>
>>>>> is
>>>>>
>>>>>>>> like 6 years old
>>>>>>>> (http://delphi.wikia.com/wiki/Borland_Compiler_Release_Dates).
>>>>>>>>
>>>>>>>> Even if you don't run the latest version, it is hardly a great
>>>>>>>>
>>>>> effort
>>>>>
>>>>>>>> to subscribe to some blogs (www.delphifeeds.com).
>>>>>>>>
>>>>>>>> As for when they came in, they are a by product of Delphi.NET.
So
>>>>>>>> codegear doing .NET was good for something! So they came into
the
>>>>>>>> win32 around D2005 and have become less buggy each release
since.
>>>>>>>>
>>>>>>>> cheers,
>>>>>>>> Jeremy
>>>>>>>>
>>>>>>>>
>>>>>>>>> Chee
>>>>>>>>>
>>>>>>>>> When did they sneak in?, Before you get all sarcastic I'd
suggest
>>>>>>>>>
>>>>> you
>>>>>
>>>>>>>>> clarify things,
>>>>>>>>> Some of us are using older versions (D6 in my case)
>>>>>>>>>
>>>>>>>> _______________________________________________
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