/* vim: set filetype=prolog : */

:- [thrash,xml].
:- dynamic pow/1.


pows(X) :-
	retractall(pow(_)),
	assert(pow(X)).

eg(1) :- pows(low), tv(X),print(X).

tv(tv(Display,Power,Input,FormaT)) :-
	display(Display),
	power(Power),
	input(Input),
	formaT(FormaT).

display(X) :- display1(X).

display1(lcd) :- pow(low).
display1(crt) :- pow(hi).

input(X) :- one(input1(X)).

input1(pwr).
input1(fr).
input1(analog).
input1(digital).

power(X) :- power1(X).

power1(volts(220)) :- pow(hi).
power1(volts(110)) :- pow(low).

formaT(X) :- one(formaT1(X)).

formaT1(ntsc).
formaT1(pal).