Upload New File

PongSource/lib/class.lua

+--[[
+Copyright (c) 2010-2013 Matthias Richter
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+Except as contained in this notice, the name(s) of the above copyright holders
+shall not be used in advertising or otherwise to promote the sale, use or
+other dealings in this Software without prior written authorization.
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
+]]--
+
+local function include_helper(to, from, seen)
+	if from == nil then
+		return to
+	elseif type(from) ~= 'table' then
+		return from
+	elseif seen[from] then
+		return seen[from]
+	end
+
+	seen[from] = to
+	for k,v in pairs(from) do
+		k = include_helper({}, k, seen) -- keys might also be tables
+		if to[k] == nil then
+			to[k] = include_helper({}, v, seen)
+		end
+	end
+	return to
+end
+
+-- deeply copies `other' into `class'. keys in `other' that are already
+-- defined in `class' are omitted
+local function include(class, other)
+	return include_helper(class, other, {})
+end
+
+-- returns a deep copy of `other'
+local function clone(other)
+	return setmetatable(include({}, other), getmetatable(other))
+end
+
+local function new(class)
+	-- mixins
+	class = class or {}  -- class can be nil
+	local inc = class.__includes or {}
+	if getmetatable(inc) then inc = {inc} end
+
+	for _, other in ipairs(inc) do
+		if type(other) == "string" then
+			other = _G[other]
+		end
+		include(class, other)
+	end
+
+	-- class implementation
+	class.__index = class
+	class.init    = class.init    or class[1] or function() end
+	class.include = class.include or include
+	class.clone   = class.clone   or clone
+
+	-- constructor call
+	return setmetatable(class, {__call = function(c, ...)
+		local o = setmetatable({}, c)
+		o:init(...)
+		return o
+	end})
+end
+
+-- interface for cross class-system compatibility (see https://github.com/bartbes/Class-Commons).
+if class_commons ~= false and not common then
+	common = {}
+	function common.class(name, prototype, parent)
+		return new{__includes = {prototype, parent}}
+	end
+	function common.instance(class, ...)
+		return class(...)
+	end
+end
+
+
+-- the module
+return setmetatable({new = new, include = include, clone = clone},
+	{__call = function(_,...) return new(...) end})
\ No newline at end of file