Re: how to refractor this ?

Hi,

It strikes me that you don’t need the variables in the head of „display_brother( X, Y )” etc.: in fact, they seem quite useless.

To answer your question: you could use call/n.  Something along the following lines:

display_relation( Relation ) :-
	setof( X - Y,  (call( Relation, X, Y ),  X @< Y), Set ),
	write( Set ).

which would then be called, e.g., by
	… display_relation( siblings ), …

Please note that I haven’t tested this code.

Hope this helps,
— Feliks

On Mar 18, 2014, at 17:07, Roelof Wobben <[email protected]> wrote:

> I have this piece: 
> 
> siblings(Child, Sibling) :-
>   same_father(Child, Sibling),
>   Child \= Sibling.
> siblings(Child, Sibling) :-
>   same_mother(Child, Sibling),
>   Child \= Sibling.
> 
> display_siblings(X,Y):-
>     setof(X-Y, (siblings(X,Y), X @< Y), Sibs),
>     write(Sibs).
> 
> brother_child(Child, Brother) :- 
>     siblings(Child, Brother), 
>     male(Brother).
> 
> display_brother(X,Y) :-
>      setof(X-Y, (brother_child(X,Y), X @< Y),Brother),
>      write(Brother).
> 
> sister_child(Child, Sister) :- 
>     siblings(Child, Sister), 
>     female(Sister).
> 
> display_sister(X,Y) :-
>      setof(X-Y, (sister_child(X,Y), X @< Y),Sister),
>      write(Sister).
> 
> As you can see the display are almost the same except the calling rule and the name of the variable.
> 
> Is there a way I can make one big display function. 
> and can I refractor more here ?
> 
> Roelof
> 
> 		 	   		  
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