Re: TRM - Morbidity has set in, or not?

David Cressey wrote:
"Marshall" <marshall.spight@xxxxxxxxx> wrote in message
news:1147886349.702914.222780@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

To achieve the big wins, though, we need a programming language that
uses the RM at its core, and that has support for physical
independence.
I am afraid that at this time this is just a wish.

I have a different take on this, slightly.

We need a programming language that has a data model as its core, and has
support for physical data independence.
The desired data model would incorporate all the benefits of the present
RDM, at the least. such a data model would probably have to incorporate the
RDM as a sub model.

I think I agree, but I'm not 100% sure I know what you mean. I observe
that a programming language will need things the ability to define and
invoke functions, have some mechanism for concurrency, I/O, etc.


The programming language also needs a highly developed process model at its
core. The object oriented process model provides a good starting place.

Not sure what you mean by "process model." That sounds like a
term for concurrency and interprocess communication, but I think
maybe you mean an inter-object communication model?


Here's where I would start:

Since the time OOP became popular, the design and construction of objects
has been revolutionized. But OOP depends on two fundamental concepts, not
just one. In an object oriented world, there are objects, and there are
messages. The messaging scheme of languages ranging from Smalltalk to Java
is woefully inadequate. There has been almost no fundamental advance here
in 30 years.

Hmmm.

First off, I must note that I dislike the Smalltalk-y term "message
passing" to denote function invocation. As a term, I think it obscures,
rather than illuminates. Also, since function invocation is necessarily
of the synchronous-request-reply kind, it pushes out other forms
of (actual) message passing from the nomenclature. And it is my
belief that actual messaging is something that belongs in the language,
rather than in a library.

Secondly, can you expand on what you mean by "woefully inadequate?"
I'm not sure I know what you mean--do you have some specific
application (ha ha) in mind?

Thirdly, I'm not sure if you're aware of what some of the more advanced
functional programming languages can do. I note: closures, passing
fuctions as parameters, returning functions as results, and partial
application. These all seem desirable to me, and are all missing from
popular OOPLs. (Unless you count, say, function pointers in C, or
inner classes as closures.)


In order to build on the successes that OOP has acheived, the messaging
scheme is going to have to go through a profound shift. When people get
around to building a better messaging scheme, they will discover that the
fundamental question is: how can objects share data coherently?

Hmmm. If you mean read-only data, then this is something of an
implementation detail. If you mean read/write data (often called
"state") then I think the right answer is externalizing them from
the object. The separately-manageable database is the right
answer.

The problem with OOP is that it sprinkles state all through your
program, like sprinkling sand into fine machinery. That state
can't be managed or inspected, except with huge difficulty.


This turns out to be the same question that database theory began working
on, back in 1970, when Codd published. It's in a different guise, but it's
the same question.

Is it possible it has the same answer now that it did then?


Marshall

.

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