basic language parsing

language.pl

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+:- [polymani].
+
+% numeros
+num('zero', 0).
+num('one', 1).
+num('two', 2).
+num('three', 3).
+num('four', 4).
+num('five', 5).
+num('six', 6).
+num('seven', 7).
+num('eight', 8).
+num('nine', 9).
+num('ten', 10).
+
+% operações
+get_num(X, Z) :- num(X, Z), !.
+get_num(X, X).
+
+parse_numbers([H|T], [N|U]) :- get_num(H, N), parse_numbers(T, U).
+parse_numbers([], []).
+
+% --
+parse_power([X, raised, to, Y | T], [K|NewT]) :-
+  number(X),
+  number(Y),
+  K is X ** Y,
+  parse_power(T, NewT),
+  !.
+parse_power([X, raised, to, Y | T], [X^Y|NewT]) :-
+  number(X),
+  parse_power(T, NewT),
+  !.
+parse_power([X, raised, to, Y | T], Z) :-
+  poly2list(X^Y, K),
+  parse_power(T, NewT),
+  append(K, NewT, Z),
+  !.
+parse_power([X, squared | T], Z) :-
+  number(X),
+  A is X**2,
+  parse_power([A|T], Z),
+  !.
+parse_power([x, squared | T], [x^2|Z]) :-
+  parse_power(T, Z),
+  !.
+parse_power([H|T], [H|Z]) :-
+  parse_power(T, Z).
+parse_power([], []).
+
+% --
+parse_multiplication([X, times, Y | T], Z) :-
+  simpoly(X*Y, A),
+  parse_multiplication([A|T], Z),
+  !.
+parse_multiplication([multiply, X, by, Y | T], Z) :-
+  simpoly(X*Y, A),
+  parse_multiplication([A|T], Z),
+  !.
+parse_multiplication([H|T], [H|Z]) :-
+  parse_multiplication(T, Z).
+parse_multiplication([], []).
+
+% --
+parse_sum([X, plus, Y|T], Z) :-
+  simpoly(X+Y, A),
+  parse_sum([A|T], Z),
+  !.
+parse_sum([H|T], [H|Z]) :-
+  parse_sum(T, Z).
+parse_sum([], []).
+
+
+parse(L, Z) :- parse_numbers(L, A), parse_power(A, B), parse_multiplication(B, C), parse_sum(C, Z).
+
+%% tests
+% parse([two, plus, x, squared], A).
+%    A = [x^2+2].
+% parse([multiply, three, by, two, plus, x, squared], B).
+%    B = [x^2+6].
+% parse([two, plus, two, plus, one, times, y], C).
+%    C = [1*y+4].