100 lines
3.4 KiB
Lua
100 lines
3.4 KiB
Lua
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--[[
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Copyright (c) 2010-2011 Matthias Richter
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Permission is hereby granted, free of charge, to any person obtaining a copy
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of this software and associated documentation files (the "Software"), to deal
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in the Software without restriction, including without limitation the rights
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to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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copies of the Software, and to permit persons to whom the Software is
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furnished to do so, subject to the following conditions:
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The above copyright notice and this permission notice shall be included in
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all copies or substantial portions of the Software.
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Except as contained in this notice, the name(s) of the above copyright holders
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shall not be used in advertising or otherwise to promote the sale, use or
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other dealings in this Software without prior written authorization.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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THE SOFTWARE.
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]]--
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local function __NULL__() end
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-- class "inheritance" by copying functions
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local function inherit(class, interface, ...)
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if not interface then return end
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assert(type(interface) == "table", "Can only inherit from other classes.")
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-- __index and construct are not overwritten as for them class[name] is defined
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for name, func in pairs(interface) do
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if not class[name] then
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class[name] = func
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end
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end
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for super in pairs(interface.__is_a or {}) do
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class.__is_a[super] = true
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end
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return inherit(class, ...)
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end
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-- class builder
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local function new(args)
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local super = {}
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local name = '<unnamed class>'
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local constructor = args or __NULL__
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if type(args) == "table" then
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-- nasty hack to check if args.inherits is a table of classes or a class or nil
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super = (args.inherits or {}).__is_a and {args.inherits} or args.inherits or {}
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name = args.name or name
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constructor = args[1] or __NULL__
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end
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assert(type(constructor) == "function", 'constructor has to be nil or a function')
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-- build class
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local class = {}
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class.__index = class
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class.__tostring = function() return ("<instance of %s>"):format(tostring(class)) end
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class.construct = constructor or __NULL__
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class.inherit = inherit
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class.__is_a = {[class] = true}
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class.is_a = function(self, other) return not not self.__is_a[other] end
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-- inherit superclasses (see above)
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inherit(class, unpack(super))
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-- syntactic sugar
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local meta = {
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__call = function(self, ...)
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local obj = {}
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setmetatable(obj, self)
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self.construct(obj, ...)
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return obj
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end,
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__tostring = function() return name end
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}
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return setmetatable(class, meta)
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end
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-- interface for cross class-system compatibility (see https://github.com/bartbes/Class-Commons).
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if common_class ~= false and not common then
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common = {}
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function common.class(name, prototype, parent)
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local init = prototype.init or (parent or {}).init
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return new{name = name, inherits = {prototype, parent}, init}
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end
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function common.instance(class, ...)
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return class(...)
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end
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end
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-- the module
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return setmetatable({new = new, inherit = inherit},
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{__call = function(_,...) return new(...) end})
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