GOOP

Gage's Object Oriented Programming

An OOP library for lua that enables all of the oop features you'd want - Along with optional type checked arguments for instantiation.

Install

Place the /GOOP anywhere you'd like in your directory and require it.

local Goop = require("libs.GOOP")

Quick Start

Goop's only function is to define a class.
For this example lets make a Person class.

local Person = Goop.Class({
    static = {
        species = "Homo sapiens"
    },
    dynamic = {
        name = "",
        age = 0
    },
    arguments = { "name", "age" }
})

local bob = Person("Bob") -- Missing arguments!
local bob = Person("Bob", 26) -- All good.

In order to inherit from this class, all we have to do is define the extends value.

local Bob = Goop.Class({
  extends = Person,
  dynamic = {
    occupation = "construction",
    name = "Bob",
    age = 26
  }
})

Type-Checking

Type checking arguments can be done easily, and at an individual level. All you have to do is define the argument as a table containing two strings - One for the string key, and one for the expected type.

local Bob = Goop.Class({
  extends = Person,
  dynamic = {
    occupation = "construction",
    name = "Bob",
    age = 26
  },
  arguments = {
    {"age", "number"}, -- MUST be a number
    {"height", "number"}, -- MUST be a number
    "weight" -- Will not be type checked.
  }
})

local bobOne = Bob(26, "170cm", "60kg") -- Invalid type arg #2 - Expected number. Received string.
local bobTwo = Bob(26, 170, "60kg") -- All good
local bobTwo = Bob(26, 170, 60) -- Also good.

init()

After all other instantiation logic, a new class instance will check if it has an init function defined, if so - It will call it and pass in any arguments it was passed when instantiated.

local Bob = Goop.Class({
  extends = Person,
  dynamic = {
    occupation = "construction",
    name = "Bob",
    age = 26
  },
  arguments = {
    {"age", "number"}, -- MUST be a number
    {"height", "number"}, -- MUST be a number
    "weight" -- Will not be type checked.
  }
})

function Bob:init(...)
    local args = {...}
    print(args[1]) -- 50
    print(args[2]) -- 170
    ...
    print(args[4]) -- "some extra argument"
end

local bobOne = Bob(50,170,"60kg","some extra argument")

Advanced class configuration

The Goop.Class function has 5 optional values.

• extends
• dynamic
• static
• arguments
• parameters

dynamic and static

These refer to the state of the class. dynamic values will be deep copied to new instances of the class when created, while static values will only be shallow copied once upon definition of the class.
This allows for better optimization - Less tables will be created over-all whenever you instantiate a new class.

If optimization isn't an issue, feel free to just use dynamic!

Parameters

This is a pretty niche feature of GOOP, and if you don't want to add any more confusion from something that most likely won't be relevant to you: I suggest you stop reading and get to goopin™.

Parameters are an alternative to arguments. Rather than providing list of arguments when instantiating a class - You provide one: a table, with key-pair values representing the state of the instance.
This allows for two things: More explicit argument definitions, and the ability to easily add custom state to the class within the instantiation function.

local Bob = Goop.Class({
  extends = Person,
  dynamic = {
    occupation = "construction",
    name = "Bob",
    age = 26
  },

  -- Defining parameters
  parameters = {
    "age",
    "height",
    "weight"
  }
})

local bobOne = Bob({age = 26, height = "170cm", weight = "60kg", eyeColor = "blue", hairColor = "black"})

You are also able to type-check parameters the same way you would arguments.

parameters = {
  {"age", "number"}, -- MUST be a number
  {"height", "number"}, -- MUST be a number
  "weight" -- Will not be type checked.
})
local bobOne = Bob({age = 26, height = "170cm", weight = "60kg"}) -- ERROR: Invalid parameter type "height". Expected "number", received "string". 

Contribution

As of writing this, this is some of the ugliest code I've ever shared with anyone. But if you would still like to contribute feel free to make a pull request :^).

Help

If you run into any issues feel free to get in touch with me on discord: @callgage

Feel free to use this in any capacity.