function out = subsref (f, x) switch x.type case "()" n = f.polynomial; out = filter(n.poly, 1, x.subs{1}); case "." fld = x.subs; if (strcmp (fld, "polynomial")) out = f.polynomial; else error ("@FIRfilter/subsref: invalid property \"%s\"", fld); endif otherwise error ("@FIRfilter/subsref: invalid subscript type for FIR filter"); endswitch endfunction