Creating Classes With Copy

This page lists some examples of some alternative organizations you can create using Copy.

Since functions are copied by reference, this method uses about the same memory as metatable classes without the re-index overhead. This also creates a proper separation between class functions and object methods, meaning Class.new().new()... is no longer possible.

List:

-- dependencies
local HttpService = game:GetService("HttpService")

local Copy = require(path.to.Copy)

-- content
local prototype = {}

local List = {
  prototype = prototype
}

-- object methods
Copy:Extend(prototype, table)

-- class methods
function List.new()
  return Copy(prototype)
end

function List.fromJSON(value)
  local data = HttpService:DecodeJSON(value)
  local self = Copy:Extend(data, prototype)
  return self
end

return List

Sorted List:

-- dependencies
local Copy = require(path.to.Copy)

-- base classes
local List = require(script.Parent.List)

-- content - inherits from List
local SortedList = Copy(List)

local prototype = SortedList.prototype

-- object methods
function prototype:insert(value)
  local index = 1
  while value > self[index] do
    index += 1
  end
  table.insert(self, index, value)
end

-- class methods
function SortedList.fromJSON(value)
  local self = List.fromJSON(value)
  Copy:Extend(self, prototype)
  self:sort()
  return self
end

return SortedList

Usage:

local SortedList = require(path.to.SortedList)

local someList = SortedList.new()

someList:insert(3)
someList:insert(2)
someList:insert(1)

print(someList) --> { 1, 2, 3 }