[Rd] [External] exists, get and get0 accept silently inputs of length > 1

[iuke-tier@ey m@iii@g oii uiow@@edu]

Worth looking into. It would probably cause some check failures, so
would probably be a good idea to run a check across BIOC/CRAN.  At the
same time it would be worth allowing name objects (type "symbol") so
thee don't have to be converted to character for the call and then
back to names internally for the environment lookup.

Best,

luke

On Fri, 13 Nov 2020, Antoine Fabri wrote:

> Dear R-devel,
>
> The doc of exists, get and get0 is unambiguous, x should be an object given
> as a character string. However these accept longer inputs. It can lead an
> uncareful user to think these functions are vectorized when they're not,
> and generally lets through bugs that one might have preferred to trigger
> earlier failure.
>
> ``` r
> exists("d")
> #> [1] FALSE
> exists(c("c", "d"))
> #> [1] TRUE
> get(c("c", "d"))
> #> function (...)  .Primitive("c")
> get0(c("c", "d"))
> #> function (...)  .Primitive("c")
> ```
>
> I believe these should either fail, or be vectorized, probably the former.
>
> Thanks,
>
> Antoine
>
> 	[[alternative HTML version deleted]]
>
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-- 
Luke Tierney
Ralph E. Wareham Professor of Mathematical Sciences
University of Iowa                  Phone:             319-335-3386
Department of Statistics and        Fax:               319-335-3017
    Actuarial Science
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