51 lines
1.5 KiB
Lua
51 lines
1.5 KiB
Lua
------------------------------------------------------------------------------
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-- Methods
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------------------------------------------------------------------------------
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--- Code from http://lua-users.org/wiki/ObjectOrientationTutorial
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---@param ... table Optional base classes
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---@return table cls A class definition
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local function make_class(...)
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-- "cls" is the new class
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local cls, bases = {}, {...}
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-- copy base class contents into the new class
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for _, base in ipairs(bases) do
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for k, v in pairs(base) do
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cls[k] = v
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end
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end
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-- set the class's __index, and start filling an "is_a" table that contains this class and all of its bases
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-- so you can do an "instance of" check using my_instance.is_a[MyClass]
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cls.__index, cls.is_a = cls, {[cls] = true}
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for _, base in ipairs(bases) do
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for c in pairs(base.is_a) do
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cls.is_a[c] = true
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end
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cls.is_a[base] = true
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end
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-- the class's __call metamethod
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setmetatable(cls, {__call = function (c, ...)
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local instance = setmetatable({}, c)
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-- run the init method if it's there
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local init = instance._init
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if init then init(instance, ...) end
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return instance
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end})
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-- return the new class table, that's ready to fill with methods
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return cls
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end
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------------------------------------------------------------------------------
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-- Module return
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------------------------------------------------------------------------------
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return make_class
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