Re: Problem with arrays.

Sathish Kumar Murugesan wrote:
> 
> I've got a problem with arrays. I need to declare a 2
> dimensional array in a program that is to be embedded
> in C++. How do I proceed with the functors [] and dim
> in the post_goal function? And how do I use the
> functor [] in the post_goal function?

There should be no difference to other functors, e.g.
to construct the term [](1,2,3) you write

	term(EC_functor("[]",3),1,2,3)


> Or is there any
> other better way to implement arrays while embedding
> in a C++ program?

The best way depends on what operations you want to
do on the arrays on the C++ and on the Eclipse side.
See the example files eg_cc_sendmore.cc and
eg_cc_sendmore.cc for related examples.


> 
> And how do I do the following from C++?
> 
> List=[A,B,C,D], Arr =.. [array|List].

It is possible, but don't make the mistake of trying
to write large parts of your Eclipse program
"through the C++ interface".

Try to miminize the interface between the languages.
Make simple calls from C++ that pass only the absolutely
necessary arguments. In your example, decide whether
to use either the array or the list on the C++ side,
and pass only that through the interface.

E.g. if you decide to use the array (= structure) on
the C++ side, you could construct it in C++

	EC_term arr = term(EC_functor("array",4),...)

and pass it as an argument to an Eclipse goal

	post_goal(EC_functor("p",1),arr)

and in the Eclipse code you would have

p(Arr) :-
	Arr =.. [array|List],
	...

or it might be easier to construct the array in Eclipse
(using functor/3 or dim/2) and pass it to C++ where it
can be deconstructed using
int EC_word::functor(EC_functor *) and
int EC_word::arg(const int,EC_word&) 


-- 
 Joachim Schimpf              /             phone: +44 20 7594 8187
 IC-Parc, Imperial College   /            mailto:J.Schimpf@ic.ac.uk
 London SW7 2AZ, UK         /    http://www.icparc.ic.ac.uk/eclipse