source: mainline/uspace/dist/src/sysel/demos/inherit.sy

--
-- Copyright (c) 2010 Jiri Svoboda
-- All rights reserved.
--
-- Redistribution and use in source and binary forms, with or without
-- modification, are permitted provided that the following conditions
-- are met:
--
-- o Redistributions of source code must retain the above copyright
--   notice, this list of conditions and the following disclaimer.
-- o Redistributions in binary form must reproduce the above copyright
--   notice, this list of conditions and the following disclaimer in the
--   documentation and/or other materials provided with the distribution.
-- o The name of the author may not be used to endorse or promote products
--   derived from this software without specific prior written permission.
--
-- THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
-- IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
-- OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
-- IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
-- INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
-- NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
-- DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
-- THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-- (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
-- THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
--

class A is
        fun Foo() is
                Console.WriteLine("A.Foo()");
        end
end

class B : A is
        fun Foo() is
                Console.WriteLine("B.Foo()");
        end
end

class C : A is
end

class InheritanceDemo is
        fun Main(), static is
                var a : A;
                var c : C;

                -- Construct and assign object.
                a = new A();
                a.Foo();

                -- Implicit conversion to base type.
                a = new B();
                a.Foo();

                a = new C();
                a.Foo();

                -- Test 'as' operator for conversion to derived type.
                c = a as C;

                -- Test grandfather class.
                var d : Object;
                d = a;
                d = new B();
                d = c;
        end
end