Repeated Evaluation

Github: https://github.com/randy3k/retry

Documentation: https://randy3k.github.io/retry

Provide simple mechanism to repeatedly evaluate an expression until either it succeeds or timeout exceeded. It is useful in situations that random failures could happen.

Installation

You can install the released version of retry from CRAN with:

install.packages("retry")

The development version could be installed with:

devtools::install_github("randy3k/retry")

Example

Some examples of retry and wait_until.

library(retry)

f <- function(x) {
    if (runif(1) < 0.9) {
        stop("random error")
    }
    x + 1
}

# keep retring when there is a random error
retry(f(1), when = "random error")
#> [1] 2
# keep retring until a requirement is satisified.
retry(f(1), until = function(val, cnd) val == 2)
#> [1] 2
# or using one sided formula
retry(f(1), until = ~ . == 2)
#> [1] 2

z <- 0
later::later(function() z <<- 1, 1)
wait_until(z == 1)
z
#> [1] 1