timeout: Run expressions with a timeout limit
In spsUtil: 'systemPipeShiny' Utility Functions

Description Usage Arguments Details Value Examples

Add a time limit for R expressions

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

`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.

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.

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

# 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