Luvit 2.5.6 Documentation

Core#

Core object model for luvit using simple prototypes and inheritance. We support single inheritance for classes.

core.instanceof(obj, class)#

Given an object which inherits from a class, and a class, returns whether the object is an instance of that class. 

> em = core.Emitter:new()
> core.instanceof(em, core.Emitter)
true

Class: core.Object#

The base object class. It provides simple prototypal inheritance and inheritable constructors. All other objects inherit from this.

Object:create()#

Creates a new instance of the base object

Object:new(...)#

Creates a new instance and calls obj:initialize(...) if it exists. 

local Rectangle = Object:extend()
function Rectangle:initialize(w, h)
  self.w = w
  self.h = h
end
function Rectangle:getArea()
  return self.w * self.h
end
local rect = Rectangle:new(3, 4)
p(rect:getArea())

Object:extend()#

Creates a new sub-class. 

local Square = Rectangle:extend()
function Square:initialize(w)
  self.w = w
  self.h = h
end

core.Emitter#

This class can be used directly whenever an event emitter is needed. 

local emitter = Emitter:new()
emitter:on('foo', p)
emitter:emit('foo', 1, 2, 3)

Also it can easily be sub-classed. 

local Custom = Emitter:extend()
local c = Custom:new()
c:on('bar', onBar)

Unlike EventEmitter in node.js, Emitter class doesn't auto binds self reference. This means, if a callback handler is expecting a self reference, utils.bind() should be used, and the callback handler should have a self at the beginning its parameter list. 

function some_func(self, a, b, c) end
emitter:on('end', utils.bind(some_func, emitter))
emitter:emit('end', 'a', 'b', 'c')

Emitter:on(name. callback)#

Adds an event listener (callback) for the named event name. 

em = Emitter:new()
em:on('data', function(data) print(data) end)

Emitter:once(name, callback)#

Same as Emitter:on except it de-registers itself after the first event.

Emitter:listenerCount(name)#

Returns the count of the listeners bound to an event with the name name

Emitter:emit(name, ...)#

Emit a named event to all listeners with optional data arguments 

> em = Emitter:new()
> em:on('data', function(data) print(data) end)
> em:emit('data', 'foo')
'foo'

Emitter:removeListener(name, callback)#

Removes a listener so it no longer catches events 

> em = Emitter:new()
> em:on('data', function(data) print(data) end)
> em:emit('data', 'foo')
foo
> em:removeListener('data', function() em:emit('data', 'foo') end)
> -- nothing printed

Emitter:removeAllListeners(name)#

Removes all listeners. Name is optional and if supplied will make it act like removeListener

Emitter:listeners(name)#

Returns listeners for the event with name name

Emitter:wrap(name)#

Utility that binds the named method self[name] for use as a callback. The first argument (err) is re-routed to the "error" event instead. 

local Joystick = Emitter:extend()
function Joystick:initialize(device)
  self:wrap("onOpen")
  FS.open(device, self.onOpen)
end
function Joystick:onOpen(fd)
  -- and so forth
end

Emitter:propagate(eventName, target)#

Propagate the event to another emitter.

core.Error#

This is for code that wants structured error messages.

Error:initialize(message)#

How to handle strings