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Re: What is OOP?

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On Sat, 29 Mar 2025 11:12:08 +0800
wij <wyniijj5@gmail.com> wrote:

> On Thu, 2025-03-27 at 18:23 +0000, Mr Flibble wrote:
> > On Mon, 17 Mar 2025 10:17:51 -0700, Tim Rentsch wrote:
> >   
> > > ram@zedat.fu-berlin.de (Stefan Ram) writes:
> > >   
> > > > Rosario19 <Ros@invalid.invalid> wrote or quoted:
> > > >   
> > > > > what is oo programming?  
> > > > 
> > > >   Alan Kay coined the term, and, in 2003, I asked him:
> > > > 
> > > > What does "object-oriented [programming]" mean to you?
> > > > 
> > > >   . He answered in an e-mail:
> > > >   
> > > > > OOP to me means only messaging, local retention and
> > > > > protection and hiding of state-process, and extreme
> > > > > late-binding of all things.  
> > > > 
> > > >   . My personal interpretation (taking the above source and my
> > > > own observations into account):  
> > > 
> > > I appreciate your efforts in pursuing this and in describing what
> > > you think it all means.  I'm glad to see a discussion about OOP
> > > that goes beyond the common misunderstandings of what is meant.
> > > 
> > > I would like to respond to your comments with my own
> > > understanding of how Alan views these areas.  I should explain
> > > that I have talked with (and also listened to) Alan enough so
> > > that I think I have a pretty good understanding of what his views
> > > are here, but the comments below are just my impression of his
> > > thoughts. 
> > > > An object is an imaginary building block that contains states
> > > > and procedures and can only be accessed from the outside by
> > > > sending messages.  The object decides how it reacts (within the
> > > > scope of its specification) to a specific message.  (runtime
> > > > model)  
> > > 
> > > An object is a blob about which nothing is known except that it
> > > is able to receive messages and act on them (which may include
> > > doing nothing at all).
> > >   
> > > > In object-oriented programming, programs describe under which
> > > > conditions which messages are sent to object expressions at
> > > > runtime: For this purpose, there is a dispatch specification
> > > > that defines the recipient object expression and the message to
> > > > be sent.  This dispatch definition can also be regarded as an
> > > > expression whose value is then determined by the recipient
> > > > object (as a type of response).  (source code model)  
> > > 
> > > The key property of object-oriented programming is that sending a
> > > message is the only way to accomplish anything.  Sending a
> > > message may start an activity and never return, or it may finish
> > > and return an object value, with the understanding that "object
> > > value" always means using pointer semantics.  There are no data
> > > values as such;  the only kinds of values in OOP are objects.
> > > 
> > > In addition to sending messages, Smalltalk has ways of using
> > > identifiers to refer to an object, of combining or sequencing
> > > message send constructs, and of assigning an object value (which
> > > again uses pointer semantics) to a named object holder (some form
> > > of identifier), but these capabilities are secondary to the key
> > > property described in the previous paragraph.
> > >   
> > > > It must be possible to determine which object receives a
> > > > particular message (late binding) as late as possible (i.e. at
> > > > runtime during the evaluation of the dispatch determination):  
> > > 
> > > The late binding that Alan is talking about is the binding of
> > > messages to processing activity.  Note the contrast with calling
> > > a function, where the binding of name to what processing is done
> > > is static rather than deferred.
> > >   
> > > > For this purpose, the recipient object can be specified again
> > > > in the dispatch determination itself by means of an expression
> > > > that is only evaluated at runtime as late as possible (runtime
> > > > polymorphism).  
> > > 
> > > It's true that the returned object value of a sent message can be
> > > used to send a further message, but that is not an occurrence of
> > > binding. Calling a function through a pointer-to-function relies
> > > on information known only at runtime, but no binding is taking
> > > place for that (except perhaps for the mapping of a variable name
> > > to a location holding the pointer-to-function value).
> > >   
> > > >   Yes, I really think it is better to say that we send messages
> > > > to expressions because which object the expression represents
> > > > is only determined shortly beforehand and can be different each
> > > > time the same code is run several times.  
> > > 
> > > Messages are always sent to objects, not to expressions.
> > > 
> > > Obviously determining an object value at runtime is useful, but
> > > it isn't any different than determining any other value at
> > > runtime. Calling a function in C that takes two arguments and
> > > returns their sum depends on values determined at runtime, but
> > > that nothing to do with late binding.
> > > 
> > > The key point is that, having gotten back an object, we can't do
> > > anything with it except send it a message, and the binding of
> > > message to what processing activity will occur always takes place
> > > at the last possible moment.
> > >   
> > > >   But there's something else of equal importance!  It's the
> > > > insight by Uncle Bob (Robert C. Martin) about when procedural
> > > > code is better and when object-oriented code is better.
> > > >   
> > > > > Procedural code (code using data structures) makes it easy to
> > > > > |add new  
> > > > functions without changing the existing data |structures.  OO
> > > > code, on the other hand, makes it easy to add |new classes
> > > > without changing existing functions.
> > > > Robert C. Martin
> > > >   
> > > > > Procedural code makes it hard to add new data structures
> > > > > |because all  
> > > > the functions must change.  OO code makes it hard |to add new
> > > > functions because all the classes must change.
> > > > Robert C. Martin  
> > > 
> > > Both of these comments make the mistake of conflating OOP with
> > > programming in languages that have classes.  That isn't what Alan
> > > meant by object-oriented programming.  That Smalltalk has classes
> > > is incidental to what is meant by object-oriented programming;
> > > classes in Smalltalk are simply a way of implementing the
> > > abstract idea of "object-oriented programming" that had started
> > > in Alan's thinking, and actually much earlier than Smalltalk or
> > > even Simula.  
> > 
> > Wrong. OOP is:
> > 
> > * Encapsulation
> > * Inheritance
> > * Polymorphism (including LSP)
> > * Abstractions
> > 
> > The above necessitates the need for classes or similar.
> > 
> > /Flibble  
> 
> Blind reciting! Or, useless (worse than none, garbage definition).
> 

Correct.

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What is OOP? wij <wyniijj5@gmail.com> - 2024-12-02 01:17 +0800
  Re: What is OOP? Ross Finlayson <ross.a.finlayson@gmail.com> - 2024-12-01 10:43 -0800
    Re: What is OOP? Ross Finlayson <ross.a.finlayson@gmail.com> - 2024-12-01 10:49 -0800
  Re: What is OOP? Lynn McGuire <lynnmcguire5@gmail.com> - 2024-12-01 15:07 -0600
    Re: What is OOP? Ross Finlayson <ross.a.finlayson@gmail.com> - 2024-12-01 13:36 -0800
    Re: What is OOP? Bonita Montero <Bonita.Montero@gmail.com> - 2024-12-02 08:45 +0100
  Re: What is OOP? Michael S <already5chosen@yahoo.com> - 2024-12-01 23:43 +0200
    Re: What is OOP? wij <wyniijj5@gmail.com> - 2024-12-02 09:02 +0800
  Re: What is OOP? Richard Damon <richard@damon-family.org> - 2024-12-01 17:02 -0500
    Re: What is OOP? wij <wyniijj5@gmail.com> - 2024-12-02 08:57 +0800
      Re: What is OOP? Richard Damon <richard@damon-family.org> - 2024-12-02 08:42 -0500
      Re: What is OOP? Isaac Ganoung <inventor500@vivaldi.net> - 2024-12-08 17:56 +0000
        Re: What is OOP? wij <wyniijj5@gmail.com> - 2024-12-09 08:28 +0800
          Re: What is OOP? wij <wyniijj5@gmail.com> - 2024-12-09 09:27 +0800
  Re: What is OOP? "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-12-01 20:11 -0800
    Re: What is OOP? wij <wyniijj5@gmail.com> - 2024-12-02 16:27 +0800
      Re: What is OOP? wij <wyniijj5@gmail.com> - 2024-12-03 20:43 +0800
  Re: What is OOP? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-12-01 20:34 -0800
    Re: What is OOP? Michael S <already5chosen@yahoo.com> - 2024-12-02 10:47 +0200
      Re: What is OOP? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-12-15 04:24 -0800
        Re: What is OOP? Michael S <already5chosen@yahoo.com> - 2024-12-15 16:33 +0200
          Re: What is OOP? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-12-16 23:59 -0800
    Re: What is OOP? wij <wyniijj5@gmail.com> - 2024-12-02 16:49 +0800
      Re: What is OOP? "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-12-02 14:59 -0800
        Re: What is OOP? wij <wyniijj5@gmail.com> - 2024-12-03 18:10 +0800
        Re: What is OOP? wij <wyniijj5@gmail.com> - 2024-12-03 18:38 +0800
          Re: What is OOP? "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-12-03 12:16 -0800
            Re: What is OOP? wij <wyniijj5@gmail.com> - 2024-12-04 08:44 +0800
              Re: What is OOP? "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-12-06 18:16 -0800
                Re: What is OOP? wij <wyniijj5@gmail.com> - 2024-12-08 01:01 +0800
                Re: What is OOP? Ross Finlayson <ross.a.finlayson@gmail.com> - 2024-12-07 10:46 -0800
              Re: What is OOP? "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-12-19 21:15 -0800
                Re: What is OOP? "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-12-19 21:16 -0800
                Re: What is OOP? "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-12-19 21:17 -0800
                Re: What is OOP? "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-12-23 15:59 -0800
    Re: What is OOP? --- The most important aspect of OOP olcott <polcott333@gmail.com> - 2024-12-06 20:40 -0600
      Re: What is OOP? --- The most important aspect of OOP Richard Damon <richard@damon-family.org> - 2024-12-06 21:45 -0500
        Re: What is OOP? --- The most important aspect of OOP olcott <polcott333@gmail.com> - 2024-12-07 14:07 -0600
        Re: What is OOP? --- The most important aspect of OOP Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-12-09 09:51 -0800
          Re: What is OOP? --- The most important aspect of OOP Ross Finlayson <ross.a.finlayson@gmail.com> - 2024-12-09 17:43 -0800
        Re: What is OOP? --- The most important aspect of OOP Mr Flibble <leigh@i42.co.uk> - 2025-03-01 21:10 +0000
      Re: What is OOP? --- The most important aspect of OOP wij <wyniijj5@gmail.com> - 2024-12-08 00:32 +0800
  Re: What is OOP? Rosario19 <Ros@invalid.invalid> - 2024-12-04 13:14 +0100
    Re: What is OOP? wij <wyniijj5@gmail.com> - 2024-12-04 22:31 +0800
    Re: What is OOP? wij <wyniijj5@gmail.com> - 2024-12-19 10:32 +0800
    Re: What is OOP? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2025-03-17 10:17 -0700
      Re: What is OOP? wij <wyniijj5@gmail.com> - 2025-03-19 04:58 +0800
        Re: What is OOP? wij <wyniijj5@gmail.com> - 2025-03-20 23:04 +0800
      Re: What is OOP? Michael S <already5chosen@yahoo.com> - 2025-03-20 17:37 +0200
        Re: What is OOP? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2025-03-29 13:33 -0700
      Re: What is OOP? Mr Flibble <flibble@reddwarf.jmc.corp> - 2025-03-27 18:23 +0000
        Re: What is OOP? wij <wyniijj5@gmail.com> - 2025-03-29 11:12 +0800
          Re: What is OOP? Mr Flibble <flibble@reddwarf.jmc.corp> - 2025-03-29 05:07 +0000
          Re: What is OOP? Michael S <already5chosen@yahoo.com> - 2025-03-29 20:39 +0300
            Re: What is OOP? Mr Flibble <flibble@reddwarf.jmc.corp> - 2025-03-29 19:03 +0000
        Re: What is OOP? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2025-03-29 13:36 -0700
  Re: What is OOP? wij <wyniijj5@gmail.com> - 2025-09-28 16:02 +0800

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