Re: Better, but not good

Now, I changed my program as followed:

%*************************************
my_fact1.
my_fact2.

alltrue([]).
alltrue([Head|Tail]) :- call(Head), alltrue(Tail).

addfacts([]).
addfacts([Head|Tail]) :- assert(Head), addfacts(Tail).

rule(L1,L2) :- ( addfacts(L2) :- alltrue(L1) ).

rule([my_fact1, my_fact2], [new_fact3]).
%*************************************

Now I get no more compiler-errors, but when I ask for "new_fact3" then it is
still unknown ("undefined_predicate")... Why?

Paul



"Paul Summer" <psummer1@yahoo.com> schrieb im Newsbeitrag
news:2s5rijF1h979eU1@uni-berlin.de...
> Hello again,
>
> I have another question to lists...
>
> Here my code:
>
> %*************************************
> my_fact1.
> my_fact2.
>
> alltrue([]).
> alltrue([Head|Tail]) :- call(Head), alltrue(Tail).
>
> rule(L1, L2) :- L2 :- alltrue(L1).       % this part don't work
>
>
> rule([my_fact1, my_fact2], [new_fact3]).
> %*************************************
>
> I want to set up rules in the following way:
>
> My rules are represented by rule(L1,L2) where L1 is a list of facts which
> must be true in order to draw the conlusions in the list L2.
> With other words: I check with "alltrue", whether L1 is completely true
> and then I want to set the members of L2 also true. To do this, I want to
> use the "rule()" in a general way. But there is a error in "rule()".
>
> What is wrong?
>
> Greetz,
>
> Paul
>
>
>

> rule(L1,L2) :- ( addfacts(L2) :- alltrue(L1) ).

Try:
rule(L1, L2) :- (alltrue(L1) -> addfacts(L2) ; true).

Dave

Thank you David,

now it works, when I type in "rule([my_fact1, my_fact2], [new_fact3])." in
the command line (then I can ask for new_fact3). But when I write the rule
directly in my source-file (as I did in my example), then I can't ask for
"new_fact3".

How can I write my rule "rule([my_fact1, my_fact2], [new_fact3])." directly
into my source-file, so that I can ask for new_fact3 and I get a "yes"?

Thanks,

Paul