persistently: Capture side effects.
In ijlyttle/warrenr: A persistently verb for purrr

Description Usage Arguments Value See Also Examples

These functions wrap functions so that instead of generating side effects through printed output, messages, warnings, and errors, they return enhanced output. They are all adverbs because they modify the action of a verb (a function).

1	persistently(.f, quiet = TRUE, max_attempts = 5, wait_seconds = 0.1)

`.f`	A function, formula, or atomic vector. See `purrr::map()`
`quiet`	Hide errors (`TRUE`, the default), or display them as they occur?
`max_attempts`	Positive integer. `persistent` functions will try to run this many times before giving up.
`wait_seconds`	Positive number. Base multiplier for time in seconds to wait between attempts. The time increases exponentially, with a wait time randomly chosen from a uniform distribution between `0` and `wait_seconds * 2 ^ (i - 1)` seconds, between the `i`th and `i + 1`th attempts.

wrapped function uses a default value (otherwise) whenever an error occurs max_attempts times.

httr::RETRY() is a special case of persistently()

# persistently() makes a function repeatedly try to work

risky_runif <- function(lo = 0, hi = 1) {
  y <- stats::runif(1, lo, hi)
  if(y < 0.9) {
    stop(y, " is too small")
  }
  y
}

persistent_risky_runif <- persistently(
  risky_runif, quiet = FALSE, wait_seconds = 0.01)

## Not run: 
  set.seed(1)
  persistent_risky_runif()
  set.seed(3)
  persistent_risky_runif()

## End(Not run)