Warning when calling formals() for `[`.
There is more "fun" afoot here, but I don't recall what the point may be:
args(get("+"))
function (e1, e2) NULL
args(get("["))
NULL
get("[")
.Primitive("[")
get("+")
function (e1, e2) .Primitive("+")
The other index operators, "[[", "[<-", "[[<-" are similar
The docs are pretty clear that args() on a primitive should yield a closure, so at least the documentation seems to be wrong.
-pd
On 6 Oct 2018, at 19:26 , Laurent Gautier <lgautier at gmail.com> wrote: 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`))
$... $na.rm [1] FALSE
is.function(`sum`)
[1] TRUE
is.primitive(`sum`)
[1] TRUE
class(`[`)
[1] "function" ``` Is this a feature ? Laurent [[alternative HTML version deleted]]
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Peter Dalgaard, Professor, Center for Statistics, Copenhagen Business School Solbjerg Plads 3, 2000 Frederiksberg, Denmark Phone: (+45)38153501 Office: A 4.23 Email: pd.mes at cbs.dk Priv: PDalgd at gmail.com