[Aldor-l] parametric types and instantiation (was: Re: Should this "parser" work?)

[Christian Aistleitner]

Hello,

On Wed, 25 Oct 2006 16:58:08 +0200, Gabriel Dos Reis  
<gdr at integrable-solutions.net> wrote:

> "Christian Aistleitner" <tmgisi at gmx.at> writes:
>
> [...]
>
> | > My understanding of it, from working on  programming language that
> | > supports both OO and parameterized type is that when you have a
> | > parameterized domain definition c
> | >
> | >
> | >    Domain(t : Type) == ...
> | >
> | > calling Domain with argument, say, Integer, is an instantiation of  
> the
> | > Domain with type Integer.
> |
> | Bear in mind, that Martin's Atom is _not_ a function. Atom is a plain,
> | constant domain.
>
> That is *irrelevant*.

Ok, then forget about the rest. Let us stick to constants.
I assume you followed the thread and know about the main problem (as  
otherwise your postings would be completely out of context and I am sure  
you would not post such “out of context” messages).

The main problem (to me) is that Martins seems to differentiate between  
“Atom" and “instance of Atom”, which can be seen by the lines
   00003000: Atom
   00003001: an instance of Atom
of the message at
http://www.aldor.org/pipermail/aldor-l/2006-October/000502.html
.

As Atom is just some, constant domain, let us replace it by  
MachineInteger, which everyone on aldor-l probably knows better.

I call the data at memory location
   (MachineInteger pretend MachineInteger)
MachineInteger. Because that's what its name MachineInteger suggests.
34 and 35 are what I call “instances of MachineInteger”.
That's what I am used to, coming from OO.
As the word “instance” is typically defined as “an occurrence” in everyday  
life, it also matches this definition.


If I am correct, you follow Martin's opinion, saying besides  
MachineInteger, there is also an “instance of the domain MachineInteger”.

I have not yet seen any evidence for such a separation. Can you provide  
Aldor code, references to the AUG underpinning your opinion or explanation  
how you think, things are working?

What is 34 called in your terminology?
“instance of a instance of the domain MachineInteger”?

As you tell me, that the difference between “MachineInteger” and “instance  
of MachineInteger” is important, they cannot coincde, as otherwise the  
difference would not be important and we would identify “MachineInteger”  
with their union.

Furthermore, if there would be only one “instance of MachineInteger”, the  
separation between them would again be not important, hence you seem to be  
saying there is more than one “instance of MachineInteger”.

When are these instances created?
How are they used?
How to they interoperate?
Does (34 at MachineInteger) always give an instantce of the same instance of  
MachineInteger?


Kind regards,
Christian