Tony,
Thanks very much for the correction. I agree completely. The real
nightmare is in not being able to ensure which object, if there can be
several of the same name within the scope, that the code is going to pickup.
With lexical scope, the developer has the responsibility and control over
th
Andy, I think you're correct that Thomas Petzoldt wants dynamic scoping, but
isn't your argument here about strong typing vs weak typing? To
paraphrase, one
could say: For example, if weak typing were allowed I might write a
function `g' that
passes argument `x' to fx() as a character, or a data
OTECTED]>
To: <[EMAIL PROTECTED]>,R-Help <[EMAIL PROTECTED]>
Subject: Re: [R] do.call and environments
The reason in your example that fx() doesn't find 'x' is that the lexical
scope of fx() does not include 'x'. So, this is what must be fixed, in one
Seems to me what you want is dynamic scoping: `x' is not defined in `fx'.
You want `x' to be found in the scope of the function(s) that calls `fx',
rather than the environment where `fx' is defined. I was told (thanks,
Robert!) that that is a very bad idea: as the author of `fx', you want some
as
The reason in your example that fx() doesn't find 'x' is that the lexical
scope of fx() does not include 'x'. So, this is what must be fixed, in one
way or another.
One simple way to make your example work is to define fx() in a place where
its lexical scope includes the variables you want it
Try this:
x <- 7
fx <- function(y) print(x*y)
f <- function(fun, x) {
myfx <- eval(parse(text=deparse(fun)))
myfx(3)
}
f(fx,2) # uses 2, not 7, for x
This creates a new function myfx which has the same functionality
as fx but is created in the body of f and therefore has that
Hello,
I want to call a function "fx" given by name, where some "global"
variables (in the environment of fx) are passed to the function. For
compatibility reasons I cannot modify the parameter list of fx and I
want to avoid setting variables in the global environment (e.g. via <<-)
Is there a
