later (version 1.4.1)

later: Executes a function later

Description

Schedule an R function or formula to run after a specified period of time. Similar to JavaScript's setTimeout function. Like JavaScript, R is single-threaded so there's no guarantee that the operation will run exactly at the requested time, only that at least that much time will elapse.

Usage

later(func, delay = 0, loop = current_loop())

Value

A function, which, if invoked, will cancel the callback. The function will return TRUE if the callback was successfully cancelled and FALSE if not (this occurs if the callback has executed or has been cancelled already).

Arguments

func

A function or formula (see rlang::as_function()).

delay

Number of seconds in the future to delay execution. There is no guarantee that the function will be executed at the desired time, but it should not execute earlier.

loop

A handle to an event loop. Defaults to the currently-active loop.

Details

The mechanism used by this package is inspired by Simon Urbanek's background package and similar code in Rhttpd.

Examples

# Example of formula style
later(~cat("Hello from the past\n"), 3)

# Example of function style
later(function() {
  print(summary(cars))
}, 2)