R help - Mar 2003 - scoping rules

Hi

I recently found a bug that was isomorphic to the following:

ll1 <- 2
increment <- function(x)
{
  l11 <- 1
  return(x+ll1)   #bug here
}

Of course, R is obeying the scoping rules just fine, but I'm evidently
not setting the do.what.I.mean.not.what.I.say variable correctly.

Now, how do I avoid making this type of error? ... and what is the
best tool for tracking it down?


-- 

Robin Hankin, Lecturer,
School of Geography and Environmental Science
Tamaki Campus
Private Bag 92019 Auckland
New Zealand

r.hankin at auckland.ac.nz
tel 0064-9-373-7599 x6820; FAX 0064-9-373-7042

On Sunday 16 March 2003 09:16 pm, Robin Hankin wrote:
> Hi
>
> I recently found a bug that was isomorphic to the following:
>
> ll1 <- 2
> increment <- function(x)
> {
>   l11 <- 1
You are not really using this variable (l11, not ll1) anywhere. Is that a 
typo? What exactly do you want to happen ?

>   return(x+ll1)   #bug here
> }
>
> Of course, R is obeying the scoping rules just fine, but I'm evidently
> not setting the do.what.I.mean.not.what.I.say variable correctly.
>
> Now, how do I avoid making this type of error? ... and what is the
> best tool for tracking it down?