spsUtil (version 0.2.2.1)

timeout: Run expressions with a timeout limit

Description

Add a time limit for R expressions

Usage

timeout(
  expr,
  time_out = 1,
  on_timeout = {
     stop("Timout reached", call. = FALSE)
 },
  on_final = {
 },
  env = parent.frame()
)

Value

default return, all depends on what return the `expr` will have

Arguments

expr

expressions, wrap them inside ``

time_out

numeric, timeout time, in seconds

on_timeout

expressions, callback expressions to run it the time out limit is reached but expression is still running. Default is to return an error.

on_final

expressions, callback expressions to run in the end regardless the state and results

env

environment, which environment to evaluate the expressions. Default is the same environment as where the `timeout` function is called.

Details

Expressions will be evaluated in the parent environment by default, for example if this function is called at global level, all returns, assignments inside `expr` will directly go to global environment as well.

Examples

# The `try` command in following examples are here to make sure the
# R CMD check will pass on package check. In a real case, you do not
# need it.

# default
try(timeout({Sys.sleep(0.1)}, time_out = 0.01))
# timeout is evaluating expressions the same level as you call it
timeout({abc <- 123})
# so you should get `abc` even outside the function call
abc
# custom timeout callback
timeout({Sys.sleep(0.1)}, time_out = 0.01, on_timeout = {print("It takes too long")})
# final call back
try(timeout({Sys.sleep(0.1)}, time_out = 0.01, on_final = {print("some final words")})) # on error
timeout({123}, on_final = {print("runs even success")})  # on success
# assign to value
my_val <- timeout({10 + 1})
my_val