Dear Jan & Duncan,
Thanks for your replies!
On Wed, 23 Jan 2019 09:56:25 -0500
Duncan Murdoch <murdoch.dun...@gmail.com> wrote:
> Defaults of variables are evaluated in the evaluation frame of the
> call. So the inside() function is created in the evaluation frame,
> and it's environment will be that frame.
> When it is called it will create a new evaluation frame (empty in
> your example), with a parent being its environment, i.e. the
> evaluation frame from when it was created, so it will be able to see
> your secret variable.
Nice explanation about closures in R inheriting not only their
explicitly captured variables, but whole environments of evaluation
(not stack) frames where they have been created.
> in my opinion it would be fine to write it as
>
> outside <- function(inside = defaultInsideFn) {
> defaultInsideFn <- function() print(secret)
> secret <- 'secret'
> inside()
> }
I like this idea; I'm going to use it.
--
Best regards,
Ivan
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