Re: Some thoughts on dicts in SWIPL 7

On 02/18/2014 11:17 AM, Carlo Capelli wrote:
> I also like dicts syntax, just missing semantic highlighting for the
> keys when used in functional notation.
> Given the small visual difference between dots and commas, porting
> cluttered code can result in difficult to spot errors.
>
> Is a patch to library(prolog_colour) underway ? Otherwise, I could try
> to do...

I had no plans, but I think it can be useful.  I still dislike the bold
keys used at the moment.  If you can find a nice colour scheme, please
send a patch.

Didn't have time to play enough with the new toys :-(

	Cheers --- Jan

P.s. still thinking whether psi-terms can/should be implemented op top
of attvars and what that should look like ...

The start can be like this:

:- module(psi,
	  [ psi/2
	  ]).

psi(Term, Features) :-
    dict_create(Dict, psi, Features),
    put_attr(Term, psi, Dict).

attr_unify_hook(Dict1, PSI2) :-
    get_attr(PSI2, psi, Dict2),
    Dict1 >:< Dict2,
    put_dict(Dict1, Dict2, Union),
    put_attr(PSI2, psi, Union).

Now you can do:

15 ?- psi(T1, [a:1, b:2]), psi(T2, [a:X, c:3]), T1 = T2.
T1 = T2,
X = 1,
put_attr(T2, psi, psi{a:1, b:2, c:3}).

Functionality-wise, this seems be close to what we want. Only the way to
create PSIs and to print them is a bit awkward. There are some
questions:

  - Is this really doing what we want?
  - How to read and write psi-terms?
  - How to realise the create/print technically?
  - What other functionality do we need on them?