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Re: What is OOP?

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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).

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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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