Re: mutable object model

Hi Alan,

It may not be exactly what you need, but I have from time to time
considered somthing similar to what you describe. Unfortunately, I'm
far to occupied with the next version of Pengines to attempt an
implementation. I share my ideas with you and with others on the list
in the hope that it will feed into further discussions.

My suggestion for a syntax, both for an immutable "record type" and
for a mutable "dictionary type" would be something like this:

{a: {b: 1},
 c: [ {d: 2}, {d:3}],
 e: foo,
 f: [4, 5, 6],
 g: @true
)

Note that:
1) This syntax is prolog readable
2) If ground, it *very* easily and naturally translates into JSON -
just transform it into SWI-Prolog's JSON terms
3) A path language able to pick out any value can easily be defined
4) A graph unification operation can be defined that allows us to
unify two immutable and "open" records
5) Assignment operation can be defined that allow us to update any
instance of a mutable dictionary
6) One could probably define a predicate able to turn any immutable
record into a mutable dictionary
7) One could probably define a predicate able to turn any mutable
dictionary into a immutable record

Oz/Mozart (http://mozart.github.io/) has such things. They are
referred to as records and dictionaries, and I have therefore used
this terminology.

I would love to have something like this.

I have no ideas for an *efficient* implementation at this point. :-(

Best regards,
Torbjörn


On Tue, Nov 12, 2013 at 7:51 PM, Alan Baljeu <[email protected]> wrote:
> What would people suggest I use for a mutable object model in Prolog?  Some specifics:
>
> An open model is preferred, like is implicit in XML and JSON specs.
> Simple XPath type queries are desired.  Select speed is paramount.
>
> Data is public.  There are no methods as such.
>
> Usually member variables would be treated logically: Initially unbound, then later bound.
>
> At times selected variables will be reset to unbound.
> Variables can share an object.
>
> Usually objects are made by instantiating classes.
>
> Standard serialization such as XML or JSON is desirable to communicate with other systems.
>
> I don't expect everything above to be ready-provided.  I'm looking for whatever might
> be an efficient and simple foundation and I'll code the rest.
>
> Alan Baljeu
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-- 
Torbjörn Lager
Professor of General and Computational Linguistics
Department of Philosophy, Linguistics and Theory of Science
University of Gothenburg
Box 200, SE-405 30 Gothenburg, Sweden
Phone: +46317864962