ELScheduler

Embeddable Lua Scheduler is a Lua module to manage timers.

Timers are bound to a point in time and are triggered when current_time >= timer_time.

Warning: Repeated timers are implemented as regular timers re-added if needed before being triggered. Thus, a timer can only be triggered once per tick; triggers may be shifted or discarded based on the tick period.

Performance note: A binary heap is used to manage timer priorities.

Install

See src/, rockspecs/ or luarocks.

API

Module

Scheduler ([time]) -> scheduler

Create a new scheduler. This function is returned when loading the module.

• time: initial time (numeric type, default is 0)

Scheduler

scheduler:timer (delay, [count, ] callback) -> timer

Create a timer.

• delay: can be <= 0 for instantaneous timers (numeric type).
• count: number of iterations (default: 1, infinite: -1)
• callback (timer): called when the timer triggers

scheduler:tick (time)

Do a scheduler tick. Time going backwards will not change/advance the scheduler's time.

• time: current time for the tick (numeric type)

Fields

• time: current time
• timers: binary heap of bound timers (as array/sequence)

The expression #self.timers gives the number of pending timers.

Timer

timer:remove ()

Remove the timer. Idempotent.

Once a timer is removed, it will never trigger again.

Fields

• scheduler: timer's scheduler
• wake: wake-up time (useful to compute delta)
• delay: period/interval (start_time = wake - delay)
• count: remaining iterations (excluding current scheduled iteration)