> Both of these are possible in C. See:
>
> https://stat.ethz.ch/pipermail/r-devel/2007-September/046943.html
Cool, thanks.
> It shows how to query an object to see if its a promise and but rather
> than extract the environment it shows how to copy a promise without
> evaluating it; however, it w
> Promises are an implementation detail -- we need to be able to change
> them, optimize them away, etc, so there is a limit on what we want to
> expose. Allowing a query of whether a binding is delayed or not
> should be OK but would want to think that through more carefully
> before committing t
On Mon, Oct 8, 2012 at 9:22 AM, Hadley Wickham wrote:
> Hi all,
>
> It's possible to capture the expression associated with a promise
> (using substitute). Is there any way to capture the environment
> associated with a promise? Similarly, is there any way to tell if
> something is a promise with
Promises are an implementation detail -- we need to be able to change
them, optimize them away, etc, so there is a limit on what we want to
expose. Allowing a query of whether a binding is delayed or not
should be OK but would want to think that through more carefully
before committing to this.
On 12-10-08 9:22 AM, Hadley Wickham wrote:
Hi all,
It's possible to capture the expression associated with a promise
(using substitute). Is there any way to capture the environment
associated with a promise? Similarly, is there any way to tell if
something is a promise without accidentally eval
Hi all,
It's possible to capture the expression associated with a promise
(using substitute). Is there any way to capture the environment
associated with a promise? Similarly, is there any way to tell if
something is a promise without accidentally evaluating it?
Thanks!
Hadley
--
RStudio / Ri
