[Rd] NOTE: multiple local function definitions for ?fun? with different formal arguments

[Duncan Murdoch]

On 04/02/2024 10:55 a.m., Izmirlian, Grant (NIH/NCI) [E] via R-devel wrote:
> Well you can see that yeast is exactly weekday you have.  The way out is to just not name the result

I think something happened to your explanation...

> 
> toto <- function(mode)
> {
>      ifelse(mode == 1,
>          function(a,b) a*b,
>          function(u, v, w) (u + v) / w)
> }

It's a bad idea to use ifelse() when you really want if() ... else ... . 
  In this case it works, but it doesn't always.  So the workaround should be


toto <- function(mode)
{
     if(mode == 1)
         function(a,b) a*b
     else
         function(u, v, w) (u + v) / w
}


> 
> 
> ________________________________
> From: Grant Izmirlian <izmirlidroid using gmail.com>
> Date: Sun, Feb 4, 2024, 10:44 AM
> To: "Izmirlian, Grant (NIH/NCI) [E]" <izmirlig using mail.nih.gov>
> Subject: Fwd: [EXTERNAL] R-devel Digest, Vol 252, Issue 2
> 
> Hi,
> 
> I just ran into this 'R CMD check' NOTE for the first time:
> 
> * checking R code for possible problems ... NOTE
> toto: multiple local function definitions for �fun� with different
>    formal arguments
> 
> The "offending" code is something like this (simplified from the real code):
> 
> toto <- function(mode)
> {
>      if (mode == 1)
>          fun <- function(a, b) a*b
>      else
>          fun <- function(u, v, w) (u + v) / w
>      fun
> }
> 
> Is that NOTE really intended? Hard to see why this code would be
> considered "wrong".
> 
> I know it's just a NOTE but still...

I agree it's a false positive, but the issue is that you have a function 
object in your function which can't be called unconditionally.  The 
workaround doesn't create such an object.

Recognizing that your function never tries to call fun requires global 
inspection of toto(), and most of the checks are based on local inspection.

Duncan Murdoch