[R] Lexical scoping is not what I expect

Duncan Murdoch murdoch.duncan at gmail.com
Tue Jun 25 00:44:30 CEST 2013


On 13-06-24 4:27 PM, David Kulp wrote:
> According to http://cran.r-project.org/doc/contrib/Fox-Companion/appendix-scope.pdf and other examples online, I am to believe that R resolves variables using lexical scoping by following the frames up the call stack.

You appear to have misread it.  Lexical scoping follows the chain of 
environments where functions were defined.  It ignores the call stack.	

Duncan Murdoch



  However, that's not working for me.  For example, the following code, 
taken from the reference above fails instead of returning 7.  What am I 
doing wrong?  Thanks!
>
> f <- function(x) { a<-5; g(x) }
> g <- function(y) { y + a }
> f(2)
> Error in g(x) : object 'a' not found
>
>
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