--
-- Copyright (c) 2011 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.
--

--- Switch statement demo.
--
-- This demonstrates the switch statement. The switch statement looks like:
--
-- switch <s_expr> is
-- when <e1> [, <e2> ...] do
--	<statements1>
-- when <f1> [, <f2> ...] do
--	<statements2>
-- [...]
-- [else do
--	<statements3>]
-- end
--
-- It is mostly equivalent to the pseudocode:
--
-- var v : <type of s_expr>;
-- if v == <e1> [or v == <e2> ...] then
--	<statements1>
-- elif v == <f1> [ or v == <f2> ...] then
--	<statements2>
-- [...]
-- [else
--	<statements3>]
-- end
--
-- This means there is no artificial limitation as to what you can switch
-- on. The expressions don't have to be constant and they can be of any type
-- as long as the switch expression (<s_expr>) can be compared with each
-- of the when expressions (<e1>, <e2>, <f1>, <f2>, ...).
--
-- Note however, the 'or' here denotes short-circuit evaluation. (Currently
-- the 'or' operation does not use short-circuit evaluation, but that's
-- more of a bug than a feature.
--
class SwitchDemo is
	class A is
	end

	var a1 : A, static;
	var a2 : A, static;
	var a3 : A, static;
	var a4 : A, static;

	enum MyEnum is
		red;
		green;
		blue;
		black;
		cyan;
	end

	-- Switch on boolean value
	fun SwitchBool(v : bool) : string, static is
		switch v is
		when false do
			return "false";
		when true do
			return "true";
		end
	end

	-- Switch on char value
	fun SwitchChar(v : char) : string, static is
		switch v is
		when 'a', 'b' do
			return "a/b";
		when 'c', 'd' do
			return "c/d";
		else do
			return "<other>";
		end
	end

	-- Switch on integer value
	fun SwitchInt(v : int) : string, static is
		switch v is
		when 0, 1 do
			return "0/1";
		when 2, 3 do
			return "2/3";
		else do
			return "<other>";
		end
	end

	-- Switch on string value
	fun SwitchString(v : string) : string, static is
		switch v is
		when "foo", "bar"  do
			return "foo/bar";
		when "hello", "world" do
			return "hello/world";
		else do
			return "<other>";
		end
	end

	-- Switch on object reference
	fun SwitchObj(v : A) : string, static is
		switch v is
		when a1, a2 do
			return "a1/a2";
		when a3, a4 do
			return "a3/a4";
		else do
			return "<other>";
		end
	end

	-- Switch on object reference
	fun SwitchEnum(v : MyEnum) : string, static is
		switch v is
		when MyEnum.red, MyEnum.green do
			return "red/green";
		when MyEnum.blue, MyEnum.black do
			return "blue/black";
		else do
			return "<other>";
		end
	end

	fun Test(res : string; test_expr : string; expected : string), static is
		Console.WriteLine(test_expr + " = '" + res + "' (expected '" +
		    expected + "')");
		if res != expected then
			Console.WriteLine("Error: Got unexpected result.");
			raise new Error.Base();
		end
	end

	fun Main(), static is
		a1 = new A();
		a2 = new A();
		a3 = new A();
		a4 = new A();

		Test(SwitchBool(false), "SwitchBool(false)", "false");
		Test(SwitchBool(true), "SwitchBool(true)", "true");

		Test(SwitchChar('a'), "SwitchChar('a')", "a/b");
		Test(SwitchChar('b'), "SwitchChar('b')", "a/b");
		Test(SwitchChar('c'), "SwitchChar('c')", "c/d");
		Test(SwitchChar('d'), "SwitchChar('d')", "c/d");
		Test(SwitchChar('e'), "SwitchChar('e')", "<other>");

		Test(SwitchInt(0), "SwitchInt(0)", "0/1");
		Test(SwitchInt(1), "SwitchInt(1)", "0/1");
		Test(SwitchInt(2), "SwitchInt(2)", "2/3");
		Test(SwitchInt(3), "SwitchInt(3)", "2/3");
		Test(SwitchInt(4), "SwitchInt(4)", "<other>");

		Test(SwitchString("foo"), "SwitchString('foo')", "foo/bar");
		Test(SwitchString("bar"), "SwitchString('bar')", "foo/bar");
		Test(SwitchString("hello"), "SwitchString('hello')", "hello/world");
		Test(SwitchString("world"), "SwitchString('world')", "hello/world");
		Test(SwitchString("boom"), "SwitchString('boom')", "<other>");

		Test(SwitchObj(a1), "SwitchObj(a1)", "a1/a2");
		Test(SwitchObj(a2), "SwitchObj(a2)", "a1/a2");
		Test(SwitchObj(a3), "SwitchObj(a3)", "a3/a4");
		Test(SwitchObj(a4), "SwitchObj(a4)", "a3/a4");
		Test(SwitchObj(nil), "SwitchObj(nil)", "<other>");

		Test(SwitchEnum(MyEnum.red), "SwitchEnum(MyEnum.red)", "red/green");
		Test(SwitchEnum(MyEnum.green), "SwitchEnum(MyEnum.green)", "red/green");
		Test(SwitchEnum(MyEnum.blue), "SwitchEnum(MyEnum.blue)", "blue/black");
		Test(SwitchEnum(MyEnum.black), "SwitchEnum(MyEnum.black)", "blue/black");
		Test(SwitchEnum(MyEnum.cyan), "SwitchEnum(MyEnum.cyan)", "<other>");
	end
end