You have now learned the fundamentals of Lua.

You have learned about variables and their types.

local my_number = 10
local my_string = "hello"
local my_boolean = true
local my_table = {}
local my_function = function () return end
local my_nil = nil

You have learned about functions. How they can have parameters. How you can pass arguments when you call them. And how they can return a value.

local function helloAnimal(animal)
    return "Hello " .. animal
end

print(helloAnimal("whale"))

You have learned about expressions.

local higher_than = 9 > 4
local lower_than = 2 < 8
local equal_to = 5 == 5
local higher_than_or_equal_to = 8 >= 3
local higher_than_or_equal_to = 4 <= 4

local arithmetic_operator = 5 * 7
local relation_operator = 8 > 2
local logical_operators = true and false
local concatenation = "Hello " .. "world"l

You have learned about control structures.

if true then
    print("if-statement")
end

for i = 1, 10 do
    print("For-loop")
end

while true do
    print("While-loop")
    break
end

repeat
    print("Repeat-until loop")
until false

And you have learned about tables, and the different ways you can use them.

Using tables as a list.

local my_list_table = {
    "item 1",
    "item 2",
    "item 3"
}

table.insert(my_list_table, "item 4")
my_list_table[5] = "item 5"

for index, value in ipairs(my_list_table) do
    print(index, value)
end

And using tables as an object.

local my_object_table = {
    property: 123
}

my_object_table["key"] = "whale"
my_object_table.dot = true

for key, value in pairs(my_object_table) do
    print(key, value)
end

Fundamentals combined #

In the demo below, we combine all the fundamentals we learned. We create a moving rectangle each time we press the left or right arrow key (make sure you click on it first). Based on the arrow key, it moves either left or right.

-- We declare the local variable rectangles, and assign a table as its value.
local rectangleList = {}

-- We create the function createRectangle.
local function createRectangle(direction)

    -- We create a new local variable named rectangle.
    -- It won't be available outside of this function.
    local rectangle = {
        -- We make it an object, and give it these properties.
        x = 375,
        y = 20,
        width = 50,
        height = 120,
        -- This will be either "left" or "right",
        -- based on what is passed as argument.
        direction = direction
    }

    -- We return the rectangle
    return rectangle
end

function love.update()
    -- We loop through the list of rectangles
    for i, rectangle in ipairs(rectangleList) do
        -- Move the rectangle to the left or right based on its direction.
        if rectangle.direction == "left" then
            rectangle.x = rectangle.x - 1
        elseif rectangle.direction == "right" then
            rectangle.x = rectangle.x + 1
        end
    end
end

function love.draw()
    -- We loop through the list of rectangles
    for i, rectangle in ipairs(rectangleList) do
        -- Draw the rectangle using its properties.
        love.graphics.rectangle("fill", rectangle.x, rectangle.y,
            rectangle.width, rectangle.height)
    end
end

function love.keypressed(key)
    -- If the key pressed is not "left" and is not "right"...
    if key ~= "left" and key ~= "right" then
        -- Go out of this function.
        return
    end

    -- We are still here, so the key is either "left" or "right".
    -- Because of the 'return', we don't need to use an 'else'.

    -- Call createRectangle, and pass the key as argument.
    -- We add its returned value to the list of rectangles.
    table.insert(rectangleList, createRectangle(key))
end