--- /dev/null
+## Copyright (C) 2009 Lukas F. Reichlin
+##
+## This file is part of LTI Syncope.
+##
+## LTI Syncope is free software: you can redistribute it and/or modify
+## it under the terms of the GNU General Public License as published by
+## the Free Software Foundation, either version 3 of the License, or
+## (at your option) any later version.
+##
+## LTI Syncope is distributed in the hope that it will be useful,
+## but WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+## GNU General Public License for more details.
+##
+## You should have received a copy of the GNU General Public License
+## along with LTI Syncope. If not, see <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*-
+## Evaluate polynomial. For internal use only.
+
+## Author: Lukas Reichlin <lukas.reichlin@gmail.com>
+## Created: September 2009
+## Version: 0.1
+
+function b = subsref (a, s)
+
+ if (isempty (s))
+ error ("tfpoly: missing index");
+ endif
+
+ switch (s(1).type)
+ case "()"
+ idx = s(1).subs;
+ if (numel (idx) == 1)
+ b = polyval (a.poly, idx{1});
+ else
+ error ("tfpoly: need exactly one index");
+ endif
+
+ otherwise
+ error ("tfpoly: invalid subscript type");
+
+ endswitch
+
+endfunction
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