Common Lisp Timer

Question

I would like to start a timer in my common lisp application that after a certain amount of time it will call a certain method. What would be the best way to accomplish this? <

Answer 1

With SBCL: make-timer and schedule-timer

SBCL has built-in functions for this.

SBCL supports a system-wide event scheduler implemented on top of setitimer that also works with threads but does not require a separate scheduler thread.

This examples executes a function after 2 seconds:

(schedule-timer (make-timer (lambda ()
                              (write-line "Hello, world")
                              (force-output)))
                2)

Among other methods we have unschedule-timer and list-all-timers.

Xach Bean's timer dates from 2003. It is possible these SBCL methods are more recent.

With Clerk, "a cron-like scheduler with a sane DSL"

With the Clerk library, we can run regular jobs:

(job "Say 'Hi' all the time" every 5.seconds (print "Hi"))

This will run every 5 seconds. Without "every" it would be a one-time job:

(job "Extraordinary event" in 5.days (send-mail "Don't forget X"))

where we can use any word instead of "in".

See also

I also encountered but didn't try https://github.com/Shinmera/simple-tasks