Hello everyone!
Would it be possible some day to use expressions as active bindings?
Something like
makeActiveExpression("foo", Expr0, env)
where Expr0 is executed in _env_ whenever "foo" is refereed.
The motivation for this question is fourfold:
- need to use <<- if the active binding is a function,
- need to create objects in the environments beforehand, to make sure <<- does
not assign them in a wrong place.
- need to set the environment for function
- active expressions would be faster (would not require the function
invocation)
So instead of :
te <- new.env()
te$tempa <- 0
myfun <- function(x){tempa <<- 33}
environment(myfun) <- te
makeActiveBinding("a", myfun, te)
one would just use:
makeActiveExpression("a", tempa <- 33) ?
I noticed that active bindings are very fast:
te$b <- expression(tempb <- 55)
system.time(evalq(for(i in 1:1e5) a, te))
user system elapsed
0.14 0.00 0.14
system.time(evalq(for(i in 1:1e5) eval(b), te))
user system elapsed
0.57 0.02 0.57
So, I would assume the active expressions would be even faster.
Thanks,
Vitalie.
______________________________________________
R-devel@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-devel
