acorn.md

Acorn: A simple OOP library.

NOTE: This library does not support inheritance, see below

To import it on your project:

• copy acorn.lua into your project
• write local acorn = require "acorn"

Usage:

local acorn = require "acorn"

local Dog = acorn.class {
    woofness = 2,

    woof = function (self)
        for x=1, self.woofness do
            print("woof!")
        end
    end
}

local fluffball = Dog()
fluffball:woof() -- Will say woof 2 times

local loud_boi = Dog()
loud_boi.woofness = 5
loud_boi:woof() -- Will say woof 5 times

No inheritance???

Yup, no inheritance. This is an intentional design choice and it's like that because it's a very opinionated library written for my own projects. I have noticed that reducing how much inheritance I add to my designs tends to allow me to write simpler and more efficient code.

If you want a neato little library with OOP + Inheritance, you can check kikito's fantastic middleclass!

Constructors

local Dog = acorn.class {
    woofness = 2,
    name = "none",

    new = function(self, name)
        self.name = name
    end,

    say_hello = function(self)
        print("woof! my name is: " .. self.name)
    end
}

local dog_1 = Dog("Puddles")
dog_1:say_hello() -- "woof! my name is: Puddles"

local dog_2 = Dog.new("Bingo")
dog_2:say_hello() -- "woof! my name is: Bingo"

local dog_3 = Dog()
dog_3:say_hello() -- "woof! my name is: none"

local dog_4 = Dog:new("Gabungi")
dog_4:say_hello() -- "woof my name is: Gabungi"

Operator overloads? Metamethods?

local dog = acorn.class {
    woofness = 2,

    woof = function (self)
        for x=1, self.woofness do
            print("woof!")
        end
    end,

    __tostring = function (self)
        return string.rep("woof! ", self.woofness)
    end
}

local doggie = dog()
print(doggie) -- woof! woof!

In this example, I replace the __tostring metamethod for a custom one which returns N amount of woof!s dependant of the woofiness. (cant believe i'm actually writing this...)

A replacement for the traditional type()

-- Type name overloads!

local dog = acorn.class {
    __type = "Dog"
}

local doggie = dog()
print(acorn.type(doggie)) -- Dog
print(acorn.type(dog)) -- Class

-- ... And it's defaults, too!

local whatever = acorn.class {}

local chair = whatever()
print(acorn.type(chair)) -- Instance
print(acorn.type(whatever)) -- Class

-- It also supports vanilla types

print(acorn.type(3)) -- number
print(acorn.type(true)) -- boolean
print(acorn.type({})) -- table
print(acorn.type("")) -- string
print(acorn.type(nil)) -- nil

The __instance property

local class = acorn.class {}
local instance = class ()

print(class.__instance) -- nil by default
print(instance.__instance) -- true by default

_{^{Name completely unrelated to Acorn Computers.}}