--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/doc/interpreter/oop.txi	Thu Oct 16 09:20:58 2008 +0100
@@ -0,0 +1,474 @@
+@c Copyright (C) 2008 David Bateman
+@c
+@c This file is part of Octave.
+@c
+@c Octave is free software; you can redistribute it and/or modify it
+@c under the terms of the GNU General Public License as published by the
+@c Free Software Foundation; either version 3 of the License, or (at
+@c your option) any later version.
+@c 
+@c Octave is distributed in the hope that it will be useful, but WITHOUT
+@c ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+@c FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+@c for more details.
+@c 
+@c You should have received a copy of the GNU General Public License
+@c along with Octave; see the file COPYING.  If not, see
+@c <http://www.gnu.org/licenses/>.
+
+@c FIXME
+@c For now can't include "@" character in the path name, and so name
+@c the example directory without the "@"!!
+
+@macro classfile{class, file}
+@example
+@group
+@verbatiminclude @value{abs_top_srcdir}/examples/\class\/\file\
+@end group
+@end example
+@end macro
+
+@macro polynomialfile{file}
+@classfile{polynomial,\file\}
+@end macro
+
+@node Object Oriented Programming
+@chapter Object Oriented Programming
+
+Octave includes the capability to include user classes, including the
+features of operator and function overloading. Equally a user class
+can be used to encapsulate certain properties of the class so that
+they can not be altered accidentally and can be set up to address the
+issue of class precedence in mixed class operations.
+
+This chapter discussions the means of constructing a user class with
+the example of a polynomial class, how to query and set the properties
+of this class, together with the means to overload operators and
+functions.
+
+@menu
+* Creating a Class::
+* Manipulating Classes::
+* Indexing Objects::
+* Overloading Objects::
+@end menu
+
+@node Creating a Class
+@section Creating a Class
+
+We use in the following text a polynomial class to demonstrate the use
+of object oriented programming within Octave. This class was chosen as
+it is simple, and so doesn't distract unnecessarily from the
+discussion of the programming features of Octave. However, even still
+a small understand of the polynomial class itself is necessary to
+fully grasp the techniques described.
+
+The polynomial class is used to represent polynomials of the form
+
+@example
+@iftex
+@tex
+$a_0 + a_1 x + a_2 x^2 + \ldots a_n x^n$
+@end tex
+@end iftex
+@ifnottex
+a0 + a1 * x + a2 * x^2 + @dots{} + an * x^n
+@end ifnottex
+@end example
+
+@noindent
+where
+@iftex
+@tex
+$a_0$, $a_1$, etc are elements of $\Re$.
+@end tex
+@end iftex
+@ifnottex
+a0, a1, etc are real scalars.
+@end ifnottex
+Thus the polynomial can be represented by a vector
+
+@example
+a = [a0, a1, a2, @dots{}, an];
+@end example
+
+We therefore now have sufficient information about the requirements of
+the class constructor for our polynomial class to write it. All object
+oriented classes in Octave, must be contained with a directory taking
+the name of the class, prepended with the @@ symbol. For example, with
+our polynomial class, we would place the methods defining the class in
+the @@polynomial directory.
+
+The constructor of the class, must have the name of the class itself
+and so in our example the constructor with have the name
+@file{@@polynomial/polynomial.m}. Also ideally when the constructor is
+called with no arguments to should return a value object. So for example
+our polynomial might look like
+
+@polynomialfile{polynomial.m}
+
+Note that the return value of the constructor must be the output of
+the @code{class} function called with the first argument being a
+structure and the second argument being the class name. An example of
+the call to this constructor function is then
+
+@example
+p = polynomial ([1, 0, 1]);
+@end example
+
+Note that methods of a class can be documented. The help for the
+constructor itself can be obtained with the constructor name, that is
+for the polynomial constructor @code{help polynomial} will return the
+help string. Also the help can be obtained by restricting the search
+for the help to a particular class, for example @code{help
+@@polynomial/polynomial}. This second method is the only means of
+getting help for the overloaded methods and functions of the class.
+
+The same is true for other Octave functions that take a function name
+as an argument. For example @code{type @@polynomial/display} will
+print the code of the display method of the polynomial class to the
+screen, and @code{dbstop @@polynomial/display} will set a breakpoint
+at the first executable line of the display method of the polynomial
+class.
+
+To check where a variable is a user class, the @code{isobject} and
+@code{isa} functions can be used. for example
+
+@example
+@group
+p = polynomial ([1, 0, 1]);
+isobject (p)
+@result{} 1
+isa (p, "polynomial")
+@result{} 1
+@end group
+@end example
+
+@DOCSTRING(isobject)
+
+@noindent
+The available methods of a class can be displayed with the
+@code{methods} function.
+
+@DOCSTRING(methods)
+
+@noindent
+To enquiry whether a particular method is available to a user class, the
+@code{ismethod} function can be used.
+
+@DOCSTRING(ismethod)
+
+@noindent
+For example
+
+@example
+@group
+p = polynomial ([1, 0, 1]);
+ismethod (p, "roots")
+@result{} 1
+@end group
+@end example
+
+@node Manipulating Classes
+@section Manipulating Classes
+
+There are a number of basic classes methods that can be defined to allow
+the contents of the classes to be queried and set. The most basic of
+these is the @code{display} method. The @code{display} method is used
+by Octave when displaying a class on the screen, due to an expression
+that is not terminated with a semicolon. If this method is not defined,
+then Octave will printed nothing when displaying the contents of a class.
+
+@DOCSTRING(display)
+
+@noindent
+An example of a display method for the polynomial class might be
+
+@polynomialfile{display.m}
+
+@noindent
+Note that in the display method, it makes sense to start the method
+with the line @code{fprintf("%s =", inputname(1))} to be consistent
+with the rest of Octave and print the variable name to be displayed
+when displaying the class. 
+
+To be consistent with the Octave graphic handle classes, a class
+should also define the @code{get} and @code{set} methods. The
+@code{get} method should accept one or two arguments, and given one
+argument of the appropriate class it should return a structure with
+all of the properties of the class. For example
+
+@polynomialfile{get.m}
+
+@noindent
+Similarly, the @code{set} method should taken as its first argument an
+object to modify, and then take property/value pairs to be modified. 
+
+@polynomialfile{set.m}
+
+@noindent
+Note that as Octave does not implement pass by reference, than the
+modified object is the return value of the @code{set} method and it
+must be called like
+
+@example
+p = set (p, "a", [1, 0, 0, 0, 1]);
+@end example
+
+@noindent
+Also the @code{set} method makes use of the @code{subsasgn} method of
+the class, and this method must be defined. The @code{subsasgn} method
+is discussed in the next section.
+
+Finally, user classes can be considered as a special type of a
+structure, and so they can be saved to a file in the same manner as a
+structure. For example
+
+@example
+@group
+p = polynomial ([1, 0, 1]);
+save userclass.mat p
+clear p
+load userclass.mat
+@end group
+@end example
+
+@noindent
+All of the file formats supported by @code{save} and @code{load} are
+supported. In certain circumstances, a user class might either contain
+a field that it makes no sense to save or a field that needs to be
+initialized before it is saved. This can be done with the
+@code{saveobj} method of the class
+
+@DOCSTRING(saveobj)
+
+@noindent
+@code{saveobj} is called just prior to saving the class to a
+file. Likely, the @code{loadobj} method is called just after a class
+is loaded from a file, and can be used to ensure that any removed
+fields are reinserted into the user object.
+
+@DOCSTRING(loadobj)
+
+@node Indexing Objects
+@section Indexing Objects
+
+Objects in can be indexed with parenthesises, either like 
+@code{@var{a} (@var{idx})} or like @code{@var{a} @{@var{idx}@}}, or even
+like @code{@var{a} (@var{idx}).@var{field}}. However, it is up to the user
+to decide what this indexing actually means. In the case of our polynomial
+class @code{@var{p} (@var{n})} might mean either the coefficient of the 
+@var{n}-th power of the polynomial, or it might be the evaluation of the 
+polynomial at @var{n}. The meaning of this subscripted referencing is 
+determined by the @code{subsref} method.
+
+@DOCSTRING(subsref)
+
+For example we might decide that indexing with "()" evaluates the
+polynomial and indexing with "{}" returns the @var{n}-th coefficient.
+In this case the @code{subsref} method of our polynomial class might look like
+
+@polynomialfile{subsref.m}
+
+The equivalent functionality for subscripted asignments uses the 
+@code{subsasgn} method.
+
+@DOCSTRING(subsasgn)
+
+If you wish to use the @code{end} keyword in subscripted expressions
+of an object. Then the user needs to define the @code{end} method for 
+the class.
+
+@DOCSTRING(end)
+
+For example the @code{end} method for our polynomial class might look like
+
+@polynomialfile{end.m}
+
+@noindent
+which is a fairly generic @code{end} method that has a behavior similar to
+the @code{end} keyword for Octave Array classes. It can then be used for
+example like
+
+@example
+@group
+p = polynomial([1,2,3,4]);
+p(end-1)
+@result{} 3
+@end group
+@end example
+
+Objects can also be used as the index in a subscripted expression themselves
+and this is controlled with the @code{subsindex} function.
+
+@DOCSTRING(subsindex)
+
+Finally, objects can equally be used like ranges, using the @code{colon}
+method
+
+@DOCSTRING(colon)
+
+@node Overloading Objects
+@section Overloading Objects
+
+@menu
+* Function Overloading::
+* Operator Overloading::
+* Precedence of Objects::
+@end menu
+
+@node Function Overloading
+@subsection Function Overloading
+
+Any Octave function can be overloaded, and allows a object specific
+version of this function to be called as needed. A pertinent example
+for our polynomial class might be to overload the @code{polyval} function
+like
+
+@polynomialfile{polyval.m}
+
+This function just hands off the work to the normal Octave @code{polyval}
+function. Another interesting example for an overloaded function for our
+polynomial class is the @code{plot} function.
+
+@polynomialfile{plot.m}
+
+@noindent
+which allows polynomials to be plotted in the domain near the region
+of the roots of the polynomial.
+
+Functions that are of particular interest to be overloaded are the class
+conversion functions such as @code{double}. Overloading these functions 
+allows the @code{cast} function to work with the user class and can aid 
+in the use of methods of other classes with the user class. An example
+@code{double} function for our polynomial class might look like.
+
+@polynomialfile{double.m}
+
+@node Operator Overloading
+@subsection Operator Overloading
+
+@float Table,tab:overload_ops
+@iftex
+@tex
+\vskip 6pt
+{\hbox to \hsize {\hfill\vbox{\offinterlineskip \tabskip=0pt 
+\halign{
+\vrule height2.0ex depth1.ex width 0.6pt #\tabskip=0.3em &
+# \hfil & \vrule # & # \hfil & \vrule # & # \hfil & # \vrule 
+width 0.6pt \tabskip=0pt\cr
+\noalign{\hrule height 0.6pt}
+& Operation && Method && Description &\cr
+\noalign{\hrule}
+& $a + b$ && plus (a, b) && Binary addition operator&\cr
+& $a - b$ && plus (a, b) && Binary subtraction operator&\cr
+& $+ a$ && uplus (a) && Unary addition operator&\cr
+& $- a$ && uminus (a) && Unary subtraction operator&\cr
+& $a .* b$ && times (a, b) && Element-wise multiplication operator&\cr
+& $a * b$ && mtimes (a, b) && Matrix multiplication operator&\cr
+& $a ./ b$ && rdivide (a, b) && Element-wise right division operator&\cr
+& $a / b$ && mrdivide (a, b) && Matrix right division operator&\cr
+& $a .\backslash b$ && ldivide (a, b) && Element-wise left division operator&\cr
+& $a \backslash b$ && mldivide (a, b) && Matrix left division operator&\cr
+& $a .\hat b$ && power (a, b) && Element-wise power operator&\cr
+& $a \hat b$ && mpower (a, b) && Matrix power operator&\cr
+& $a < b$ && lt (a, b) && Less than operator&\cr
+& $a <= b$ && le (a, b) && Less than or equal to operator&\cr
+& $a > b$ && gt (a, b) && Greater than operator&\cr
+& $a >= b$ && ge (a, b) && Greater than or equal to operator&\cr
+& $a == b$ && eq (a, b) && Equal to operator&\cr
+& $a != b$ && ne (a, b) && Not equal to operator&\cr
+& $a \& b$ && and (a, b) && Logical and operator&\cr
+& $a | b$ && or (a, b) && Logical or operator&\cr
+& $! b$ && not (a) && Logical not operator&\cr
+& $a'$ && ctranspose (a) && Complex conjugate transpose operator &\cr
+& $a.'$ && transpose (a) && Transpose operator &\cr
+& $a : b$ && colon (a, b) && Two element range operator &\cr
+& $a : b : c$ && colon (a, b, c) && Three element range operator &\cr
+& $[a, b]$ && horzcat (a, b) && Horizontal concatenation opertaor &\cr
+& $[a; b]$ && vertcat (a, b) && Vertical concatenation opertaor &\cr
+& $a(s_1, \ldots, s_n)$ && subsref (a, s) && Subscripted reference &\cr
+& $a(s_1, \ldots, s_n) = b$ && subsasgn (a, s, b) && Subscripted assignment &\cr
+& $b (a)$ && subsindex (a) && Convert to zero-based index &\cr
+& {\it display} && display (a) && Commandline display function &\cr
+\noalign{\hrule height 0.6pt}
+}}\hfill}}
+@end tex
+@end iftex
+@ifnottex
+@multitable @columnfractions .1 .20 .20 .40 .1
+@item @tab Operation @tab Method @tab Description @tab
+@item @tab a + b @tab plus (a, b) @tab Binary addition @tab
+@item @tab a - b$ @tab plus (a, b) @tab Binary subtraction operator @tab
+@item @tab + a$ @tab uplus (a) @tab Unary addition operator @tab
+@item @tab - a$ @tab uminus (a) @tab Unary subtraction operator @tab
+@item @tab a .* b$ @tab times (a, b) @tab Element-wise multiplication operator @tab
+@item @tab a * b$ @tab mtimes (a, b) @tab Matirx multiplication operator @tab
+@item @tab a ./ b$ @tab rdivide (a, b) @tab Element-wise right division operator @tab
+@item @tab a / b$ @tab mrdivide (a, b) @tab Matrix right division operator @tab
+@item @tab a .\ b$ @tab ldivide (a, b) @tab Element-wise left division operator @tab
+@item @tab a \ b$ @tab mldivide (a, b) @tab Matrix left division operator @tab
+@item @tab a .^ b$ @tab ldivide (a, b) @tab Element-wise power operator @tab
+@item @tab a ^ b$ @tab mldivide (a, b) @tab Matrix power operator @tab
+@item @tab a < b$ @tab lt (a, b) @tab Less than operator @tab
+@item @tab a <= b$ @tab le (a, b) @tab Less than or equal to operator @tab
+@item @tab a > b$ @tab gt (a, b) @tab Greater than operator @tab
+@item @tab a >= b$ @tab ge (a, b) @tab Greater than or equal to operator @tab
+@item @tab a == b$ @tab eq (a, b) @tab Equal to operator @tab
+@item @tab a != b$ @tab ne (a, b) @tab Not equal to operator @tab
+@item @tab a \& b$ @tab and (a, b) @tab Logical and operator @tab
+@item @tab a | b$ @tab or (a, b) @tab Logical or operator @tab
+@item @tab ! b$ @tab not (a) @tab Logical not operator @tab
+@item @tab a'$ @tab ctranspose (a) @tab Complex conjugate transpose operator @tab
+@item @tab a.'$ @tab transpose (a) @tab Transpose operator @tab
+@item @tab a : b$ @tab colon (a, b) @tab Two element range operator @tab
+@item @tab a : b : c$ @tab colon (a, b, c) @tab Three element range operator @tab
+@item @tab [a, b]$ @tab horzcat (a, b) @tab Horizontal concatenation opertaor @tab
+@item @tab [a; b]$ @tab vertcat (a, b) @tab Vertical concatenation opertaor @tab
+@item @tab a(s_1, \ldots, s_n)$ @tab subsref (a, s) @tab Subscripted reference @tab
+@item @tab a(s_1, \ldots, s_n) = b$ @tab subsasgn (a, s, b) @tab Subscripted assignment @tab
+@item @tab b (a)$ @tab subsindex (a) @tab Convert to zero-based index @tab
+@item @tab  @dfn{display} @tab display (a) @tab Commandline display function @tab
+@end multitable
+@end ifnottex
+@caption{Available overloaded operators and their corresponding class method}
+@end float
+
+An example @code{mtimes} method for our polynomial class might look like
+
+@polynomialfile{mtimes.m}
+
+@node Precedence of Objects
+@subsection Precedence of Objects
+
+Many functions and operators take two or more arguments and so the
+case can easily arise that these functions are called with objects of
+different classes. It is therefore necessary to determine the precedence
+of which method of which class to call when there are mixed objects given
+to a function or operator. To do this the @code{superiorto} and
+@code{inferiorto} functions can be used
+
+@DOCSTRING(superiorto)
+
+@DOCSTRING(inferiorto)
+
+For example with our polynomial class consider the case
+
+@example
+2 * polynomial ([1, 0, 1]);
+@end example
+
+@noindent
+That mixes an object of the class "double" with an object of the class
+"polynomial". In this case we like to ensure that the return type of
+the above is of the type "polynomial" and so we use the
+@code{superiorto} function in the class constructor. In particular our
+polynomial class constructor would be modified to be
+
+@polynomialfile{polynomial_superiorto.m}
+
+Note that user classes always have higher precedence than built-in
+Octave types. So in fact marking our polynomial class higher than the 
+"double" class is in fact not necessary.
+
+

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/examples/polynomial/Makefile.in	Thu Oct 16 09:20:58 2008 +0100
@@ -0,0 +1,93 @@
+# Makefile for octave's scripts/geometry directory
+#
+# Copyright (C) 2007 John W. Eaton
+#
+# This file is part of Octave.
+# 
+# Octave 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.
+# 
+# Octave 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 Octave; see the file COPYING.  If not, see
+# <http://www.gnu.org/licenses/>.
+
+TOPDIR = ../..
+
+script_sub_dir = polynomial
+
+srcdir = @srcdir@
+top_srcdir = @top_srcdir@
+VPATH = @srcdir@
+
+include $(TOPDIR)/Makeconf
+
+INSTALL = @INSTALL@
+INSTALL_PROGRAM = @INSTALL_PROGRAM@
+INSTALL_DATA = @INSTALL_DATA@
+
+SOURCES = \
+  display.m \
+  double.m \
+  end.m \
+  get.m \
+  mtimes.m \
+  plot.m \
+  polynomial.m \
+  polynomial_superiorto.m \
+  polyval.m \
+  set.m \
+  subsasgn.m \
+  subsref.m
+
+DISTFILES = $(addprefix $(srcdir)/,Makefile.in $(SOURCES))
+
+FCN_FILES = $(addprefix $(srcdir)/, $(SOURCES))
+FCN_FILES_NO_DIR = $(notdir $(FCN_FILES))
+
+all: PKG_ADD
+.PHONY: all
+
+install install-strip:
+.PHONY: install install-strip
+
+uninstall:
+.PHONY: uninstall
+
+clean:
+.PHONY: clean
+
+PKG_ADD: $(FCN_FILES)
+	@echo "making PKG_ADD"
+	@$(do-mkpkgadd)
+
+tags: $(SOURCES)
+	ctags $(SOURCES)
+
+TAGS: $(SOURCES)
+	etags $(SOURCES)
+
+mostlyclean: clean
+.PHONY: mostlyclean
+
+distclean: clean
+	rm -f Makefile PKG_ADD
+.PHONY: distclean
+
+maintainer-clean: distclean
+	rm -f tags TAGS
+.PHONY: maintainer-clean
+
+dist:
+	ln $(DISTFILES) ../../`cat ../../.fname`/examples/$(script_sub_dir)
+.PHONY: dist
+
+check-m-sources:
+	@$(do-check-m-sources)
+.PHONY: check-m-sources

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/examples/polynomial/display.m	Thu Oct 16 09:20:58 2008 +0100
@@ -0,0 +1,33 @@
+function display (p)
+  a = p.poly;
+  first = true;
+  fprintf("%s =", inputname(1));
+  for i = 1 : length (a);
+    if (a(i) != 0)
+      if (first)
+	first = false;
+      elseif (a(i) > 0)
+	fprintf (" +");
+      endif
+      if (a(i) < 0)
+	fprintf (" -");
+      endif
+      if (i == 1)
+	fprintf (" %g", abs (a(i)));
+      elseif (abs(a(i)) != 1)
+	fprintf (" %g *", abs (a(i)));
+      endif
+      if (i > 1)
+	fprintf (" X");
+      endif
+      if (i > 2)
+	fprintf (" ^ %d", i - 1);
+      endif
+    endif
+  endfor
+  if (first)
+    fprintf(" 0");
+  endif
+  fprintf("\n");
+endfunction
+

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/examples/polynomial/double.m	Thu Oct 16 09:20:58 2008 +0100
@@ -0,0 +1,3 @@
+function b = double (a)
+  b = a.poly;
+endfunction

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/examples/polynomial/end.m	Thu Oct 16 09:20:58 2008 +0100
@@ -0,0 +1,11 @@
+function r = end (obj, index_pos, num_indices)
+  dv = size (obj.x);
+  for i = (num_indices + 1) : length (dv)
+    dv(num_indices) *= dv(i);
+  endfor
+  if (index_pos <= length (dv))
+    r = dv (index_pos);
+  elseif
+    r = 1;
+  endif
+endfunction

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/examples/polynomial/get.m	Thu Oct 16 09:20:58 2008 +0100
@@ -0,0 +1,18 @@
+function s = get (p, f)
+  if (nargin == 1)
+    s.poly = p.poly;
+  elseif (nargin == 2)
+    if (ischar (f))
+      switch (f)
+	case "poly"
+	  s = p.poly;
+	otherwise
+	  error ("get: invalid property %s", f);
+      endswitch
+    else
+      error ("get: expecting the property to be a string");
+    endif
+  else
+    print_usage ();
+  endif
+endfunction

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/examples/polynomial/mtimes.m	Thu Oct 16 09:20:58 2008 +0100
@@ -0,0 +1,5 @@
+function y = mtimes (a, b)
+  ap = double (a);
+  bp = double (b);
+  y = polynomial (filter (ap, 1, [bp(:).', zeros(1, length(bp) - 1)]));
+endfunction
\ No newline at end of file

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/examples/polynomial/plot.m	Thu Oct 16 09:20:58 2008 +0100
@@ -0,0 +1,10 @@
+function h = plot(p, varargin)
+  n = 128;
+  rmax = max (abs (roots (p.poly)));
+  x = [0 : (n - 1)] / (n - 1) * 2.2 * rmax - 1.1 * rmax;
+  if (nargout > 0)
+    h = plot(x, p(x), varargin{:});
+  else
+    plot(x, p(x), varargin{:});
+  endif
+endfunction
\ No newline at end of file

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/examples/polynomial/polynomial.m	Thu Oct 16 09:20:58 2008 +0100
@@ -0,0 +1,28 @@
+## -*- texinfo -*-
+## @deftypefn {Function File} {} polynomial ()
+## @deftypefnx {Function File} {} polynomial (@var{a})
+## Creates a polynomial object representing the polynomial
+##
+## @example
+## a0 + a1 * x + a2 * x^2 + @dots{} + an * x^n
+## @end example
+## @end deftypefn
+
+function p = polynomial (a)
+  if (nargin == 0)
+    p.poly = [];
+    p = class (p, "polynomial");
+  elseif (nargin == 1)
+    if (strcmp (class (a), "polynomial"))
+      p = a;
+    elseif (isvector (a) && isreal (a))
+      p.poly = a(:)';
+      p = class (p, "polynomial");
+    else
+      error ("polynomial: expecting real or complex vector")
+    endif
+  else
+    print_usage ();
+  endif
+  superiorto ("double");
+endfunction

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/examples/polynomial/polynomial_superiorto.m	Thu Oct 16 09:20:58 2008 +0100
@@ -0,0 +1,18 @@
+function p = polynomial (a)
+  if (nargin == 0)
+    p.poly = [];
+    p = class (p, "polynomial");
+  elseif (nargin == 1)
+    if (strcmp (class (a), "polynomial"))
+      p = a;
+    elseif (isvector (a) && isreal (a))
+      p.poly = a(:)';
+      p = class (p, "polynomial");
+    else
+      error ("polynomial: expecting real or complex vector")
+    endif
+  else
+    print_usage ();
+  endif
+  superiorto ("double");
+endfunction

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/examples/polynomial/polyval.m	Thu Oct 16 09:20:58 2008 +0100
@@ -0,0 +1,7 @@
+function [y, dy] = polyval (p, varargin)
+  if (nargout == 2)
+    [y, dy] = polyval (p.poly, varargin{:});
+  else
+    y = polyval (p.poly, varargin{:});
+  endif
+endfunction

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/examples/polynomial/set.m	Thu Oct 16 09:20:58 2008 +0100
@@ -0,0 +1,20 @@
+function s = set (p, varargin)
+  s = p;
+  if (length (varargin) < 2 || rem (length (varargin), 2) != 0)
+    error ("set: expecting property/value pairs");
+  endif
+  while (length (varargin) > 1)
+    prop = varargin{1};
+    val = varargin{2};
+    varargin(1:2) = [];
+    if (ischar (prop) && strcmp (prop, "poly"))
+      if (isvector (val) && isreal (val))
+	s.poly = val(:)';
+      else
+	error ("set: expecting the value to be a real vector");
+      endif
+    else
+      error ("set: invalid property of polynomial class");
+    endif
+  endwhile
+endfunction
\ No newline at end of file

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/examples/polynomial/subsasgn.m	Thu Oct 16 09:20:58 2008 +0100
@@ -0,0 +1,12 @@
+function s = subsasgn (s, index, val)
+  switch (index.type)
+    case "()"
+      if (! isnumeric (val) || iscomplex(val) ||any (val(:)) >= 2.^ s.m || 
+	  any (val(:)) < 0 || any (val(:) != fix(val(:))))
+	error ("subsasgn: value must be an array of real integers between 0 and 2.^m - 1");
+      endif
+      s.x = subsasgn (s.x, index, double (val));
+    case "."
+      error ("subsagn: can not set properties of a galois field directly");
+  endswitch
+endfunction

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/examples/polynomial/subsref.m	Thu Oct 16 09:20:58 2008 +0100
@@ -0,0 +1,17 @@
+function b = subsref (a, s)
+  switch s.type
+    case "()"
+      ind = s.subs;
+      b = polyval (fliplr(a.poly), ind{:});
+    case "{}"
+      ind = s.subs;
+      b = polynomial (a.poly(ind{:}));
+    case "."
+      fld = s.subs;
+      if (strcmp (fld, "poly"))
+	b = a.poly;
+      else
+	error ("subsref: unrecognized property \"%s\" of a polynomial", fld);
+      endif
+  endswitch
+endfunction