🚀 go-pugleaf

Mike,

I think i mis-understood what you were after, ie equality matching rather than
unification. So  (ummm) is this the kind of thing you want?

That the kind of thing, so you can supply constants or variables?
how about ....

fuzzy_unify(A,B) :-
    fuzzy_range(FR),
    not( var(A) ),
    not( var(B) ), !,
    Diff is A - B,
    absolute_value(Diff,Abs_Diff),
    Abs_Diff < FR.

fuzzy_unify(A,B) :-
    fuzzy_range(FR),
    not( var(A) ),
    var(B), !,
    random(Rand),   
    Addition is FR * Rand,
    random_sign(Sign),           % returns -1 or +1
    B is (Sign*Addition) + A.
    
fuzzy_unify(A,B) :-
    fuzzy_range(FR),
    var(A),
    not( var(B) ), !,
    fuzzy_unify(B,A).       % allows A or B it be variables
    
fuzzy_unify(A,A), !.


so  either A or B or Both can be variable, plus it works if NO fuzzy_range is
specified.  Hope that is of more help,  J.  ucjtrjf@ucl.ac.uk