Re: Siblings of parents

Thanks, 


I changed it to this:


male(roelof). 

male(mans).

male(jan).


female(chantal). 

female(tamara). 

female(marie). 


parent(roelof,tamara).

parent(mans, roelof). 

parent(jan, chantal). 

parent(marie, roelof). 

parent(chantal, tamara). 


is_mother(Child,Mother):- 

parent(Mother, Child),

female(Mother),



is_father(Child, Father):- 

parent(Father, Child),

male(Father),





siblings(Father,Mother) :- 

is_father(X, Father), 

is_mother(X, mother).


So father and mother has siblings if father is the father of X and mother is the mother of X. 


But still errors like this: User throw: error(system_error, [type = exec, rc = 427, message = `Syntax error: Probable missplaced period around: (is_mother(H223, H224) :- parent(H224, H223) , female(H224) , is_father(H223, H240)) :- parent(H240, H223) , male(H240) , siblings(H240, H224)`, predicate = `err$exec/4`, callstack = `- catch/3;+ catch/3;- consult/1;--- top of stack ---`])


Roelof

----------------------------------------
> Subject: Re: [SWIPL] Siblings of parents
> From: [email protected]
> Date: Sat, 8 Mar 2014 17:35:22 +0100
> To: [email protected]
>
>
> On 8 Mar 2014, at 17:29 , Roelof Wobben <[email protected]> wrote:
>
>> siblings(F,M) :-
>>
>> father(X)
>>
>> mother(X).
>>
>>
>>
>> So I thougth to display if parents have siblings X have to have a father and a mother.
>
> Check the meaning of these clauses. Do they express what you want to express?
>
> Another suggestion: Have a look at http://www.learnprolognow.org to get the basics of Prolog.
>
> --- nef
>