[DIRECT-L] V4MD: question: Xtra which create another Xtra ?

[Ruslan Zasukhin]

On 7/16/04 8:59 PM, "John Mathis" <john2 at inplicity.com> wrote:

Hi John,

> Although I can't think of an applicable example using xtras, I don't think
> there is any architectural limitation on doing that.
> 
> I know that you can achieve exactly that structure using scripts...I do it
> all the time...I'm just foggy on the xtras part.

Scripts ? ....

But scripts this is only feature of Lingo itself, right?

We develop Valentina Database Xtra itself. So scripts I think is not
solution...

Practical usage I have show already. In c++, Java, REALbasic versions of
Valentina we have classes

    Vdatabase
    Vtable
    Vfield
    Vcursor
    Vset
    Vlink
    ......


    db = new Vdatabase

    Vtable tbl = db.CreateTable( "Person" )

    Vfield fld = tbl.CreateField( "FirstName", kTypeVarChar, 2000, fIdexed )


As you see we have chain of calls.
Supervisor class can create new instance of other class.

With XDK as far as I see we cannot do this.
Bad.


> John
> 
> ----- Original Message -----
> From: "Ruslan Zasukhin" <sunshine at public.kherson.ua>
> To: <DIRECT-L at LISTSERV.UARK.EDU>
> Sent: Friday, July 16, 2004 12:39 PM
> Subject: [DIRECT-L] V4MD: question: Xtra which create another Xtra ?
> 
> 
>> Hi Director experts,
>> 
>> In C/C++ and REALbasic we can write
>> 
>>     Set* set = field.Find( 5 )
>> 
>> Function find() have create and return object of new class.
>> 
>> And C++ and REALbasic and Java and in each normal OO language
>> This is MUST BE feature.
>> 
>> In Director/Lingo I never have such syntax.
>> 
>> So can we do in Lingo something as:
>> 
>> 
>>         db = new (Xtra "Vdatabase")
>> 
>>         tbl = db.CreateTable( "Person" )
>> 
>> 
>> Here tbl must be of type (Xtra "VTable")
>> 
>> Is this possible in Lingo?
>> 
>> If yes, then how effective this ?
>> 
>> If no, then why no ?  :-)
>> Lingo looks claims that it have some OO features.
>> So why it not have such basic feature of OO language ?

-- 
Best regards,
Ruslan Zasukhin      [ I feel the need...the need for speed ]
-------------------------------------------------------------
e-mail: ruslan at paradigmasoft.com
web: http://www.paradigmasoft.com

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