| New arithmetic functions programmed in MINERVA are used exactly
as built in functions.
This allows both functional and relational notations for arithmetic expressions.
MINERVA predicates for arithmetic evaluation, e.g. is/2
used on a function like "Result = f(A,...,N)" will
search for a predicate "f(A,...,N,Result)".
Thus arithmetic in MINERVA becomes easier to read and uses
aggresive variable hiding.
% example: compute the cost for industrial urethane foam
% notation as relations
a(Price) :-
height(H), width(W), depth(D),
unit_price_per_volume(U),
Price is H * W * D * U.
% notation as functions
b(Price) :-
Price is height * width * depth * unit_price_per_volume.
% uniform notation of functions resp. data base
height(6).
depth(38).
width(75).
unit_price_per_volume(0.01).
Here is the result for the above program:
?- a(Price).
Price = 171.0
yes
?- b(Price).
Price = 171.0
yes
?-
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