Hi,
A short code example showing the warning might the only thing needed here:
```
> formals(args(`[`))
NULL
*Warning message:In formals(fun) : argument is not a function*
> is.function(`[`)
[1] TRUE
> is.primitive(`[`)
[1] TRUE
```
Now with an other primitive:
```
> formals(args(`sum`))
$...
Hello,
I believe that this is maybe not a *feature* but at least expected
behaviour.
The call formals(args(`[`)) breaks down to
> args(`[`)
NULL
> formals(NULL)
NULL
Warning message:
In formals(fun) : argument is not a function
Hope this helps,
Rui Barradas
Às 18:26 de 06/10/2018, Laure
Hello,
I forgot to ask you to also try to break the `sum` instruction into its
components:
args(`sum`)
does return a function. Therefore formals(args(`sum`)) returns something
useable and no warning.
Rui Barradas
Às 18:42 de 06/10/2018, Rui Barradas escreveu:
Hello,
I believe that this
Hi,
Thanks for the note. How would explain the following snippet taken from
`formals` doc page (the code comment is also from that doc) ?
## formals returns NULL for primitive functions. Use it in combination with
## args for this case.
is.primitive(`+`)
formals(`+`)
formals(
