R help - Oct 2004 - control enviromnet

Hi all:

I would like to implement an option in my function so that it warns me of any 
variables that are not defined in the current environment - if it needs to 
look up variables in the parent frame, it tells me so. 

The following is an example and it does what I want, and I'd rather have the
environment control option inside this function instead of outside. Any help 
would be greatly appreciated.

x = 1
test = function(y) {
 ans = y + x;
 return(ans);
}
environment(test)=NULL
test(y = 1)

Thanks much!

Fang

I think you want something like

exists("x", where = environment(), inherits = FALSE)

-roger

facS93 at hampshire.edu wrote:
> Hi all:
> 
> I would like to implement an option in my function so that it warns me of
any
> variables that are not defined in the current environment - if it needs to 
> look up variables in the parent frame, it tells me so. 
> 
> The following is an example and it does what I want, and I'd rather
have the
> environment control option inside this function instead of outside. Any
help
> would be greatly appreciated.
> 
> x = 1
> test = function(y) {
>  ans = y + x;
>  return(ans);
> }
> environment(test)=NULL
> test(y = 1)
> 
> Thanks much!
> 
> Fang
> 
> ______________________________________________
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http://www.R-project.org/posting-guide.html
>

<facS93 <at> hampshire.edu> writes:

: 
: Hi all:
: 
: I would like to implement an option in my function so that it warns me of 
any 
: variables that are not defined in the current environment - if it needs to 
: look up variables in the parent frame, it tells me so. 
: 
: The following is an example and it does what I want, and I'd rather have
the
: environment control option inside this function instead of outside. Any help 
: would be greatly appreciated.
: 
: x = 1
: test = function(y) {
:  ans = y + x;
:  return(ans);
: }
: environment(test)=NULL
: test(y = 1)
: 

Here is one way.  

x <- 1
test <- function(y) {
	test <- function(y) x+y
	environment(test) <- NULL
	test(y)
}
test(9) # gives required error