44 lines
1.2 KiB
Lua
44 lines
1.2 KiB
Lua
---Declare table as a base class
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---@generic T
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---@param cls T # class metatable
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---@param o? table # initial parameters
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---@return T # class instance
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function Base(cls, o)
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o = o or {}
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cls.__index = cls
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setmetatable(o, cls)
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return o
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end
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local function search(key, bases)
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for _, base in ipairs(bases) do
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local v = base[key] -- try `i'-th superclass
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if v then return v end
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end
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end
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---Declare table as a derived class
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---@generic BaseT, T
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---@param cls T # class metatable
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---@param o? table # initial parameters
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---@param ... BaseT # base class metatables
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---@return T # derived class instance
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function Inherit(cls, o, ...)
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o = o or {}
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local nargs = select("#", ...)
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local vargs = { select(1, ...) }
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cls.__index = cls
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if nargs > 1 then
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setmetatable(cls, {__index = function(t, k) return search(k, vargs) end})
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for _, base in ipairs(vargs) do
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o = base:new(o)
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end
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else
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local base = assert(vargs[1], "You must at least specify one class to inherit from.")
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setmetatable(cls, {__index = base})
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o = base:new(o)
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end
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setmetatable(o, cls)
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return o
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end
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