From hadley at rice.edu  Fri May 14 16:20:51 2010
From: hadley at rice.edu (Hadley Wickham)
Date: Fri, 14 May 2010 09:20:51 -0500
Subject: [Rd] Restrict access to variables in parent environment
In-Reply-To: <AANLkTine-6pPbbOKspjOxOFF7qYC56KItUn_apBUKSgy@mail.gmail.com>
References: <AANLkTine-6pPbbOKspjOxOFF7qYC56KItUn_apBUKSgy@mail.gmail.com>
Message-ID: <AANLkTinVN5_uVkOaryuBnmw5JTYWdqWRojFRdG41hC-7@mail.gmail.com>

> Hello All,
>
> By default, a reference of a variable in a function cause R to look
> for the variable in the parent environment if it is not available in
> the current environment (without generating any errors or warnings).
> I'm wondering if there is a way to revert this behaviors, such that it
> will not look for the parent environment and will generate an error if
> the variable is not available in the current environment. Is this
> tuning has to be done at the C level?

Try this:
b <- 1
f <- function(a) {
  b
}

environment(f) <- baseenv()
f()

Hadley

-- 
Assistant Professor / Dobelman Family Junior Chair
Department of Statistics / Rice University
http://had.co.nz/



[Rd] Restrict access to variables in parent environment
Hadley Wickham