getOption benchmark

bench.R

getOptionOld <- function(x, default = NULL) {
    if(missing(default) || x %in% names(options()))
      .Internal(getOption(x))
    else
      default
}

getOptionNew <- function(x, default = NULL) {
  ans <- .Internal(getOption(x))
  if(is.null(ans)) default else ans
}

bench <- microbenchmark::microbenchmark(
  old_found = getOptionOld("width"),
  old_missing = getOptionOld("blah"),
  old_missing_default = getOptionOld("blah", "foo"),
  new_found = getOptionNew("width"),
  new_missing = getOptionNew("blah"),
  new_missing_default = getOptionNew("blah", "foo")
)
bench
# Unit: nanoseconds
#                 expr   min    lq      mean  median       uq     max neval
#            old_found     0   293    431.26   294.0    587.0     880   100
#          old_missing   293   294    680.53   587.0    587.0   11437   100
#  old_missing_default 92373 93399 123949.44 98237.5 100437.5 2642732   100
#            new_found     0   293    451.90   294.0    587.0    2933   100
#          new_missing   293   294  16991.01   587.0    733.0 1639832   100
#  new_missing_default   293   294    536.86   586.0    587.0    1174   100

# Would need to lookup a missing option with a default 10,000 times before this
# would take more than ~1 second.
system.time({ i <- 1; while((i <- i + 1) <= 10000) getOptionOld("blah", "foo") })
#     user  system elapsed 
#    1.01    0.00    1.02