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Re: About concurrency and functional programming

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On 01/03/15 11:34, Robert Klemme wrote:
> On 01.03.2015 09:41, Robbie Brown wrote:
>> On 01/03/15 02:28, Jerry Stuckle wrote:
>>> On 2/28/2015 4:26 PM, Robbie Brown wrote:
>>>> On 28/02/15 18:56, Joshua Cranmer 🐧 wrote:
>>>>> On 2/27/2015 6:45 PM, Ramine wrote:
>>>>>> You will notice that "Bartosz Milewski" is saying that object
>>>>>> oriented

<snip>

>> Actually, I find that people often get composition and aggregation mixed
>> up,
>
> And now you even mix up the topic of the discussion: it was composition
> vs. inheritance.

It was a passing comment. Your attempt at ridicule is disingenuous.

<snip>

>> C 'is a' B. Is C composite by inheritance?
>
> Not sure what that is supposed to mean.

What is it you don't understand? I can't think of a clearer way to 
express this in the English language.

Instances of classes are implementation details. They are the result
of trying to express a real world, possibly infinite concept in a finite 
approximation of that world (a computer). Don't get upset if you don't 
understand it, it seems strange at first but it's quite simple really. 
Anyway, I think I understand what the OP means.

> C inherits B and as such
> instances of C contain an instance of A as well.  So in sum, C makes use
> of both concepts but for different purposes.
>
>> C is certainly 'a B' but B can't 'exist' without C and dies when C dies.
>
> No, C does not die but _instances_ of C die!

You shouldn't be thinking about 'instances' at a high level of 
abstraction, that's the point of abstraction, you ignore irrelevant 
details so you have space in your brain to consider higher level concerns.

> That's a huge difference.

No, there really isn't, not at a particular level of abstraction.

<snip>

>> B has no meaning or purpose in the
>> system without C, a classic description of composition.
>
> The purpose of B is to inherit from it (either because it represents an
> abstract concept or purely for implementation inheritance purposes).  If
> there is no class inheriting it then it _may_ be superfluous but the
> fact does not change the purpose of B.  Otherwise all interfaces defined
> in libraries are without purpose if not at least one class in the
> library implements it.  That is silly.

I see, an interface that nothing implements is not superfluous ... OK (?)

> I recommend reading "Object Oriented Software Construction" by Bertrand
> Meyer.  That is the most profound work on various aspects of OO and
> inheritance I am aware of.  You'll be hard pressed to find a language
> that has more ways to do inheritance (and a few other things) than Eiffel.

I have read many books on OO, written several manuals and training 
courses on OO Software Engineering with Java and designed many computer 
systems, and I have used Eiffel. I'm happy that I 'get' this stuff and 
am always interested in what other people think. I have no entrenched 
ideas and prefer to believe that I am free thinking and open to ideas 
from experts and beginners alike, however, I do try to avoid personal 
insults however as they serve no purpose.

Rob

-- 
Not floundering ... just fishing

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Re: About concurrency and functional programming Joshua Cranmer 🐧 <Pidgeot18@verizon.invalid> - 2015-02-28 12:56 -0600
  Re: About concurrency and functional programming Robbie Brown <rob@example.com> - 2015-02-28 21:26 +0000
    Re: About concurrency and functional programming Jerry Stuckle <jstucklex@attglobal.net> - 2015-02-28 21:28 -0500
      Re: About concurrency and functional programming Robbie Brown <rob@example.com> - 2015-03-01 08:41 +0000
        Re: About concurrency and functional programming Robert Klemme <shortcutter@googlemail.com> - 2015-03-01 12:34 +0100
          Re: About concurrency and functional programming Robbie Brown <rob@example.com> - 2015-03-01 14:26 +0000
            Re: About concurrency and functional programming Joerg Meier <joergmmeier@arcor.de> - 2015-03-01 15:30 +0100
              Re: About concurrency and functional programming Robbie Brown <rob@example.com> - 2015-03-01 14:31 +0000
            Re: About concurrency and functional programming Robbie Brown <rob@example.com> - 2015-03-01 14:30 +0000
            Re: About concurrency and functional programming Jerry Stuckle <jstucklex@attglobal.net> - 2015-03-01 11:29 -0500
              Re: About concurrency and functional programming Robbie Brown <rob@example.com> - 2015-03-01 17:07 +0000
                Re: About concurrency and functional programming Joerg Meier <joergmmeier@arcor.de> - 2015-03-01 20:12 +0100
                Re: About concurrency and functional programming Robbie Brown <rob@example.com> - 2015-03-01 20:31 +0000
                Re: About concurrency and functional programming Jerry Stuckle <jstucklex@attglobal.net> - 2015-03-01 16:13 -0500
                Re: About concurrency and functional programming Jerry Stuckle <jstucklex@attglobal.net> - 2015-03-01 16:11 -0500
                Re: About concurrency and functional programming Jerry Stuckle <jstucklex@attglobal.net> - 2015-03-01 16:17 -0500
    Re: About concurrency and functional programming Joshua Cranmer 🐧 <Pidgeot18@verizon.invalid> - 2015-03-01 12:03 -0600

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