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
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 was
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 /
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
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 Mon, Oct 8, 2012 at 9:22 AM, Hadley Wickham h.wick...@gmail.com 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
