Code for comment to https://xianblog.wordpress.com/2010/09/13/simply-start-over-and-build-something-better

comment.R

library(nofrills)

x <- 0

# make x local by pegging it to an argument
f1 <- fn(x = !!x ~ {
  if (runif(1) > .5)
    x <- 10
  x
})

# assign local x to global x at the time of f2's creation (not call)
f2 <- fn(~ {
  x <- !!x
  if (runif(1) > .5)
    x <- 10
  x
})

# even when x changes in the lexical scope, f1 and f2 don't
x <- 1
replicate(10, f1())  # only contains 0's or 10's
replicate(10, f2())  # ditto