http://vpaste.net/z8GQx The category shows both methods, but only has one of them public: the one it defined locally. The one it's implementing from the protocol is not public. But NEITHER of them, whether flagged public or not, is actually showing in the object that imports the category.
I can call these imported methods using ::/1 from within the foo object, however.
What does "public" mean on an interface? A category? And why do the docs at https://logtalk.org/manuals/userman/categories.html#importing-categories seem to imply that public predicates should import publicly? Or am I have serious reading difficulties?
This message was deleted
This is correct:
?- object_property(foo, Prop).
Prop = context_switching_calls ;
Prop = source_data ;
Prop = static ;
Prop = file('/Users/pmoura/junk.lgt') ;
Prop = file('junk.lgt', '/Users/pmoura/') ;
Prop = lines(24, 27) ;
Prop = (public[]) ;
Prop = protected([]) ;
Prop = private([]) ;
Prop = number_of_clauses(0) ;
Prop = number_of_rules(0) ;
Prop = number_of_user_clauses(0) ;
Prop = number_of_user_rules(0).
But what you're looking for is:
?- foo::current_predicate(P).
P = fc_method/0 ;
P = fp_method/0 ;
false.
?- foo::predicate_property(fp_method, P).
P = logtalk ;
P = scope(public) ;
P = (public) ;
P = static ;
P = declared_in(foo_protocol) ;
P = declared_in(foo_protocol, 3) ;
P = defined_in(foo_category) ;
P = defined_in(foo_category, 12) ;
P = number_of_clauses(1) ;
P = number_of_rules(1).
?- foo::predicate_property(fc_method, P).
P = logtalk ;
P = scope(public) ;
P = (public) ;
P = static ;
P = declared_in(foo_category) ;
P = declared_in(foo_category, 10) ;
P = defined_in(foo_category) ;
P = defined_in(foo_category, 17) ;
P = number_of_clauses(1) ;
P = number_of_rules(1).
You need to read the chapter on reflection in the Logtalk handbook. You want the behavioral reflection API, not the structural reflection API.
When I "implement" a protocol that has a method flagged "public" I would expect that method to be available. It isn't.
When I "import" a category that has public methods, I would expect that method to be available. It isn't.
The properties thing there was just to show that it's going in weird places I don't expect.
Which is the expected results.
?- foo::fc_method.
! Permission error: access protected_predicate fc_method/0
! in goal: foo::fc_method
! with execution context:
! entity: user
! sender: user
! this: user
! self: A
! meta-call context: []
! coinduction stack: []
! The predicate is protected and not within the scope of the sender or caller.
!
! Permission error: access protected_predicate fc_method/0
! in goal: foo::fc_method
! with execution context:
! entity: user
! sender: user
! this: user
! self: A
! meta-call context: []
! coinduction stack: []
! The predicate is protected and not within the scope of the sender or caller.
!
This is the unexpected result I'm getting.
OK, I have no idea what's going on. When I return to the original code it started working. Which leads me to believe I typoed something earlier.
There's nothing declared public inside the object.
I'm having troubles doing a simple "Hello world" with it. :-/
:- object(hello).
:- multifile(logtalk::message_tokens//2).
:- dynamic(logtalk::message_tokens//2).
logtalk::message_tokens(hello, hello(What)) -->
['Hello, ~w!'-[What], nl].
:- public(main/0).
main :- logtalk::print_message(information, hello, hello('World')).
:- end_object.
I'm calling print_message telling it to print an information message from component hello using hello/1.
?- {hello}.
% [ /home/michael/junk/hello.lgt loaded ]
% (0 warnings)
true.
?- hello::main.
% Unknown information message for component hello: hello('World')
true.
I'm just missing that step where it actually knows what component hello, or token hello/1 (it's unclear where the problem is) actually are.
YungTseTech_twitter @YungTseTech_twitter facepalms.
print_message is type, component, term while message_tokens is term, component.
Is this an indexing hack?
I'd hitherto been using write/writeln/nl.
Meta-messages can avoid the need of writing tokenization rules in common cases.