EventEmitter

Events in julia

Julia package to easly implement event pattern in julia

Installation

using Pkg; Pkg.add("EventEmitter")

License

All code licensed under the MIT license.

Getting started

First run

using EventEmitter

Construct an Event

myevent = Event()

You can pass callback functions as arguments

myfunction() = println("function")
myevent = Event(myfunction, () -> println("Arrow function"))

Listeners are on by default. change this by setting once

myevent = Event((x) -> print(x); once=true)

Or construct listeners manually and pass them

# Listener(callback, once)
myevent = Event(Listener(() -> 1), Listener(() -> 2, true))

Use on!() or once!() to add listeners

on!(myevent) do
  return "called everytime"
end
once!(myevent) do
  return "called once"
end

Emit an event by calling it or using emit!()

myevent() # [1, 2, "called everytime", "called once"]
emit!(myevent) # [1, "called everytime"]

Listeners are called in order

myevent = Event(() -> 1, () -> 2)
on!(myevent, () -> 3)

myevent() # [1, 2, 3]

Use prependlisteners!() to prepend listeners

prependlisteners!(myevent, () -> 4, () -> 5)
myevent() # [4, 5, 1, 2, 3]

Use off!() to remove a Listener

*off!() returns the Listener it removes, so doing off!(event)() will call it*

off!(myevent)() # 3 - (last) equivalent to `off!(myevent, 0)()`
off!(myevent, 1)() # 4 - (first)
off!(myevent, -1)() # 1 - (before last)
myevent() # [5, 2]

Construct collections of Events (arrays, tuples, named tuples and dictionaries)

event1 = Event(() -> 1)
event2 = Event(() -> 2)
arr = [event1, event2]
tuple = (event1, event2)
namedtuple = (a=event1, b=event2)
dict = Dict(:a => event1, :b => event2)

Emit the collections

*emitting a dict will give almost random order for the events*

emit!(arr) # [[1], [2]]
emit!(tuple) # [[1], [2]]
emit!(namedtuple) # [[1], [2]]
emit!(dict) # [[1], [2]]