Modifying Class Object

[Alf P. Steinbach]

* Michael Sparks:
> 
[Due to the appearance of reasoned discussion (it's not practical to read it 
all!), I felt it necessary to respond. It turned out to be a long sequence of 
trivial fallacies, peppered with various allegations and insinuations.]


[snip extremely much]

> Now let's move to the implementation aspects.
> 
> Python as a language is implemented in many languages. One of these
> is C. There are compilers to C (pypy), C++ (shedskin), for the JVM
> (Jython) and .net (Ironpython).
> 
> There is also an executable operation semantics for python,
> which can be found here:
> 
> http://gideon.smdng.nl/2009/01/an-executable-operational-semantics-for-python/
> 
> This set of operational semantics is written in Haskell.
> 
> Haskell is a strictly pure, lazily evaluated language. It
> therefore has no pointers or references, just values and names.
> The implementation therefore cannot be in terms of references
> and pointers.

At this point consider whether it's possible to implement Pascal in Haskell.

If it is possible, then you have a problem wrt. drawing conclusions about 
pointers in Pascal, uh oh, they apparently can't exist.

But if it is not possible to implement Pascal in Haskell, then Haskell must be 
some etremely limited special-purpose language, not Turing complete  --  is that 
acceptable to you?


> Therefore to say "in reality the implementation
> will be passing a reference or pointer" is invalid. There is
> after all at least one implementation that does not rely on
> such machine oriented language details.

I'm sorry, but see above: in itself it's just yet another a fallacy.

And as an argument in a debate with me it's misrepresenting.

There is need to talk about "in reality" (as if the language spec and general 
semantics isn't real enough) nor to talk about any specific implementation.


[snip very much]

> I sincerely hope that my reply does not offend or inflame you,
> since that is not the intent. I do hope it educates you and
> puts into context the responses you have gained from others.
> 
> After all, one simply shouting in a corner saying "YOU'RE
> ALL WRONG, WRONG, WRONG. I'M RIGHT RIGHT RIGHT", when one
> does not to understand what one is talking about does not
> tend to engender warm fluffy feelings or sentiments of
> authority towards such an individual. Be it me, you, or
> anyone else.
> 
> At the moment, you appear to me to be engaging in such a
> behaviour. Now you don't know from Jack and probably don't
> care about  my viewpoint, but I would really appreciate it
> if you would try not to be inflammatory in your response
> to this. (Since you do appear to also have a need to have
> the last word)
> 
> Hoping this was useful on some level,

Yes.

I elected to respond to just /one/ of the many arguments you presented.

The other arguments, about why there are no references in Python, shared, 
however, the basic property of being logical fallacies packaged in kilometers of 
rambling text.


Cheers,

- Alf