middleclass

A simple OOP library for Lua. It has inheritance, metamethods (operators), class variables and weak mixin support.

Notes about this fork

This fork adds a symlink to middleclass.lua file in lua/ directory to allow using middleclass repo with Neovim plugin managers. I have opened a pull request to merge this into upstream. Also for convenience, this repo has a copy of upstream wiki.

Since Neovim 0.5 most new plugins become written in Lua. Lua allows some sort of OOP based on metatables, and most of the plugins which use OOP has a class.lua file with practically identical code. To reduce the amount of boilerplate code, I created this fork and suggest to use it as a standard class realization.

Quick Look

local class = require 'middleclass'

local Fruit = class('Fruit') -- 'Fruit' is the class' name

function Fruit:initialize(sweetness)
  self.sweetness = sweetness
end

Fruit.static.sweetness_threshold = 5 -- class variable (also admits methods)

function Fruit:isSweet()
  return self.sweetness > Fruit.sweetness_threshold
end

local Lemon = class('Lemon', Fruit) -- subclassing

function Lemon:initialize()
  Fruit.initialize(self, 1) -- invoking the superclass' initializer
end

local lemon = Lemon:new()

print(lemon:isSweet()) -- false

Documentation

See the github wiki page for examples & documentation.

You can read the CHANGELOG.md file to see what has changed on each version of this library.

If you need help updating to a new middleclass version, read UPDATING.md.

Installation

Just copy the middleclass.lua file wherever you want it (for example on a lib/ folder). Then write this in any Lua file where you want to use it:

local class = require 'middleclass'

Specs

This project uses busted for its specs. If you want to run the specs, you will have to install it first. Then just execute the following:

cd /folder/where/the/spec/folder/is
busted

Performance tests

Middleclass also comes with a small performance test suite. Just run the following command:

lua performance/run.lua

License

Middleclass is distributed under the MIT license.