91 lines
1.9 KiB
Lua
91 lines
1.9 KiB
Lua
--
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-- classic
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--
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-- Copyright (c) 2014, rxi
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--
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-- This module is free software; you can redistribute it and/or modify it under
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-- the terms of the MIT license. See LICENSE for details.
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--
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-- https://github.com/rxi/classic
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--
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---@class (exact) Class
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---@field super Class
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---@field private implements table<Class, boolean>
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local Class = {}
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Class.__index = Class ---@diagnostic disable-line: inject-field
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---Default constructor
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function Class:new(...) --luacheck: ignore 212
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end
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---Extend a class, setting .super
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function Class:extend()
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local cls = {}
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for k, v in pairs(self) do
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if k:find("__") == 1 then
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cls[k] = v
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end
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end
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cls.__index = cls
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cls.super = self
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setmetatable(cls, self)
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return cls
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end
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---Implement the functions of a mixin
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---Add the mixin to .implements
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---@param mixin Class
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function Class:implement(mixin)
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if not rawget(self, "implements") then
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-- set on the class itself instead of parents
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rawset(self, "implements", {})
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end
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self.implements[mixin] = true
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for k, v in pairs(mixin) do
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if self[k] == nil and type(v) == "function" then
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self[k] = v
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end
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end
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end
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---Object is an instance of class or implements a mixin
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---@generic T
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---@param class T
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---@return boolean
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function Class:is(class)
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local mt = getmetatable(self)
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while mt do
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if mt == class then
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return true
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end
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if mt.implements and mt.implements[class] then
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return true
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end
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mt = getmetatable(mt)
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end
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return false
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end
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---Return object if :is otherwise nil
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---@generic T
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---@param class T
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---@return T|nil
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function Class:as(class)
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return self:is(class) and self or nil
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end
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---Constructor to create instance, call :new and return
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function Class:__call(...)
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local obj = setmetatable({}, self)
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obj:new(...)
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return obj
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end
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-- avoid unused param warnings in abstract methods
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---@param ... any
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function Class:nop(...) --luacheck: ignore 212
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end
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return Class
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