vars(P)={
    my(v=List(),x);
    while(type(P)=="t_POL",
        x=variable(P);
        listput(v,x);
        P=subst(P,x,1)
    );
    Vec(v)
};
truthTable(P)={
    my(var=vars(P),t,b);
    for(i=0,2^#var-1,
        t=eval(P);
        for(j=1,#var,
            b=bittest(i,j-1);
            t=subst(t,var[j],b);
            print1(b)
        );
        print(!!t)
    );
};
truthTable("x+y") \\ OR
truthTable("x*y") \\ AND