local

Declares a new variable in the current block scope.

A variable is a container for a value. For example, a variable might contain a creature's x-coordinate as a number or its name as a string. Variables can change value by reassigning them as follows:

local x = 10

-- Reassign x to 50.
x = 50

Note: Unlike JavaScript and Java, when a variable is declared without prepending local such as x = 10 it is global by default, even when declared inside a function. In contrast, declaring a variable with local means it only exists within the block defined by its start and closing end. For example, the following code would print an output of nil because x is declared as a local variable within the setup() function's block:

function setup() 
  size(100, 100)

  local x = 50
end

function draw() 
  background(200)

  -- x was declared in setup(), so it can't be referenced here.
  circle(x, 50, 20) --will result in x being nil
end

Variables declared without local are in the global scope. A variable that's in the global scope can be used and changed anywhere in a sketch:

function setup() 
  createCanvas(100, 100)

  x = 50 --created without local, so is global
end

function draw() 
  background(200)

  -- Change the value of x.
  x = x + 10

  circle(x, 50, 20)
end

Examples

local example 1

function setup()
  size(100, 100)

  background(220)

  -- Style the text.
  textAlign(CENTER)
  textSize(16)
  fill('black')
  windowTitle("variable creation.")

  -- Create the message variable.
  local message = 'Hello, L5!'

  -- Display the message.
  text(message, 50, 50)

  describe('The text "Hello, L5!" written on a gray background.')
end

local example 2

local x = 0

function setup()
  size(100, 100)

  describe('A white circle moves from left to right against a gray background.')
end

function draw()
  background(220)

  -- Change the value of x.
  x = x + 1

  circle(x, 50, 20)
end

local

Examples

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