Re: 1GB Tables as Classes, or Tables as Types, and all that refuted
From: Costin Cozianu <c_cozianu_at_hotmail.com>
Date: Tue, 14 Dec 2004 11:18:41 -0800
Message-ID: <328slaF3ip88sU1_at_individual.net>
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> I agree on that the definitions are not good :)
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> But it is essential to know what an object is for him. It is a
> fundamental omission.
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> What is an object instance and what is the difference between an
> object instance and an object?
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> In the OO world, instance is often another synonym of value, state and
> object.
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> So an instance variable is a variable that is a component of a
> variable, so an object is a composed variable. But variables don't
> have methods, methods are members of types.
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> A few lines below he says that objects are references, he is confusing
> the pointer typed variables (his references) with the referenced
> variables (the variables formed by the collection of instance
> variables).
>
> The definitions are very tied to the physical level because a logical
> variable does not have components, it is simply a holder for a value
> of some type. A value may have different representations and the
> representations may have components.
>
> The class definition is terribly sloppy. He is confusing a model level
> concept with the source code, the language syntax and the
> implementation.
>
> If he is one of the most serious OO authors what can we expect from
> the others?
>
> I was looking in Pierce's papers and books but I don't find any
> definition of the typical OO concepts.
>
>
> Regards
>
>
Date: Tue, 14 Dec 2004 11:18:41 -0800
Message-ID: <328slaF3ip88sU1_at_individual.net>
Alfredo Novoa wrote:
> On Sun, 12 Dec 2004 16:46:57 -0800, Costin Cozianu
> <c_cozianu_at_hotmail.com> wrote:
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>>>Object: >>> >>>Objects encapsulate both state and behavior. In particular they >>>consist of a collection of instance variables, representing the state >>>of the object, and a collection of methods, representing the behavior >>>that the object is capable of performing. The methods are routines >>>that are capable of accessing and manipulating the values of the >>>instance variables of the object... >>>As is the case in Java and Smalltalk, we wil assume that all objects >>>are implicit references... >>> >>>Class: >>> >>>Classes are extensible templates for creating objects, providing >>>initial values for instance variables and the bodies for methods. All >>>objects generated from the same class share the same methods, but >>>contain separate copies of the instance variables. New objects can be >>>created from a class by applying the new operator to the name of the >>>class. >>> >>>I have not found any definition for instance variable, and the >>>sloppiness and contradictions are evident.
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>>This is a bunch of BS, Alfredo.
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> I agree on that the definitions are not good :)
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>>A defintion for instance variable if Kim >>Bruce has not put it in, is trivial.
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>
> But it is essential to know what an object is for him. It is a
> fundamental omission.
>
>
>>It's a name "x" such that given a >>reference to an object instance r, r.x can be used to denote the value
>
>
> What is an object instance and what is the difference between an
> object instance and an object?
>
> In the OO world, instance is often another synonym of value, state and
> object.
>
>
>>of the component x and can also be used on the left side of the >>assignment to modify the value of the component x.
>
>
> So an instance variable is a variable that is a component of a
> variable, so an object is a composed variable. But variables don't
> have methods, methods are members of types.
>
> A few lines below he says that objects are references, he is confusing
> the pointer typed variables (his references) with the referenced
> variables (the variables formed by the collection of instance
> variables).
>
> The definitions are very tied to the physical level because a logical
> variable does not have components, it is simply a holder for a value
> of some type. A value may have different representations and the
> representations may have components.
>
> The class definition is terribly sloppy. He is confusing a model level
> concept with the source code, the language syntax and the
> implementation.
>
> If he is one of the most serious OO authors what can we expect from
> the others?
>
> I was looking in Pierce's papers and books but I don't find any
> definition of the typical OO concepts.
>
>
> Regards
>
>
Can you tell me where did Date define what a variable was ?
Costin Received on Tue Dec 14 2004 - 20:18:41 CET