From murdoch@dunc@n @end|ng |rom gm@||@com  Sun Feb  4 18:07:24 2024
From: murdoch@dunc@n @end|ng |rom gm@||@com (Duncan Murdoch)
Date: Sun, 4 Feb 2024 12:07:24 -0500
Subject: [Rd] NOTE: multiple local function definitions for ?fun? with
 different formal arguments
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Message-ID: <5cb29a06-5b73-4fe4-b8dc-7aa9db6a2cff@gmail.com>

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 at gmail.com>
> Date: Sun, Feb 4, 2024, 10:44 AM
> To: "Izmirlian, Grant (NIH/NCI) [E]" <izmirlig at 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



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