#	numerical limit
#	e.g. nlim(sin(x)/x, x=0) gives 1;
#	See also : lim;
#nlim(y_, l_=r_) := n(replace(y, l, r+10^(-10)));
#nlim(y_):=n(replace(y, x, 10^(-10)));


nlim(a_+b_,x_,x0_):=nlim(a,x,x0)+nlim(b,x,x0);
nlim(y_,x_):=nlim(y,x,0);
nlim(y_, x_=x0_, dir_) := nlim(y,x,x0,dir);
nlim(y_, x_=x0_) := nlim(y,x,x0);
nlim(y_):=nlim(y,x,0);