Re: mutable object model

Torbjörn, Alan,

You may be interesting to hear that the next major release of
SWI-Prolog will provide `maps' as primary citizens that are
supported throughout the system (parsing, writing, efficient
low-level operations).  YAP is likely to copy these features.
Just hold on ...

	Cheers --- Jan

On 11/12/2013 11:31 PM, Torbjörn Lager wrote:
> 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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> 
>