>>>>> Joris Meys <jorism...@gmail.com>
>>>>> on Tue, 28 Mar 2017 15:19:14 +0200 writes:
> Thank you gents, I overlooked the subtle differences.
> On Tue, Mar 28, 2017 at 2:49 PM, Lukas Stadler <lukas.stad...@oracle.com>
> wrote:
>> “typeof” is your friend here:
>>
>> > typeof(`[`)
>> [1] "special"
>> > typeof(mc[[1]])
>> [1] "symbol"
>> > typeof(mc2[[1]])
>> [1] "special"
>>
>> so mc[[1]] is a symbol, and thus not a primitive.
or str() which should be better known to Joe Average useR
> mc <- call("[",iris,2,"Species")
> str(mc[[1]])
symbol [
> str(`[`)
.Primitive("[")
>
>> - Lukas
>>
>> > On 28 Mar 2017, at 14:46, Michael Lawrence <lawrence.mich...@gene.com>
>> wrote:
>> >
>> > There is a difference between the symbol and the function (primitive
>> > or closure) to which it is bound.
>> >
>> > This:
>> > mc2 <- as.call(list(`[`,iris,2,"Species"))
>> >
>> > Evaluates `[` to its value, in this case the primitive object, and the
>> > primitive itself is incorporated into the returned call.
>> >
>> > If you were to do this:
>> > mc2 <- as.call(list(quote(`[`),iris,2,"Species"))
>> >
>> > The `[` would _not_ be evaluated, quote() would return the symbol, and
>> > the symbol would end up in the call.
>> >
>> > The two forms have virtually identical behavior as long as the call
>> > ends up getting evaluated in the same environment.
>> >
>> > On Tue, Mar 28, 2017 at 3:03 AM, Joris Meys <jorism...@gmail.com>
wrote:
>> >> Dear,
>> >>
>> >> I have noticed this problem while looking at the following question on
>> >> Stackoverflow :
>> >>
>> >> http://stackoverflow.com/questions/42894213/s4-class-
>> subset-inheritance-with-additional-arguments
>> >>
>> >> While going through callNextMethod, I've noticed the following odd
>> >> behaviour:
>> >>
>> >> mc <- call("[",iris,2,"Species")
>> >>
>> >> mc[[1]]
>> >> ## `[`
>> >>
>> >> is.primitive(`[`)
>> >> ## [1] TRUE
>> >>
>> >> is.primitive(mc[[1]])
>> >> ## [1] FALSE
>> >> # Expected to be TRUE
>> >>
>> >> mc2 <- as.call(list(`[`,iris,2,"Species"))
>> >>
>> >> is.primitive(mc2[[1]])
>> >> ## [1] TRUE
>> >>
>> >> So depending on how I construct the call (using call() or as.call() ),
>> the
>> >> function `[` is or is not recognized as a primitive by is.primitive()
>> >>
>> >> The behaviour is counterintuitive and -unless I miss something obvious
>> >> here- likely to be a bug imho. I immediately admit that my C chops
>> aren't
>> >> sufficient to come up with a patch.
>> >>
>> >> Cheers
>> >> Joris
>> >>
>> >> --
>> >> Joris Meys
>> >> Statistical consultant
>> >>
>> >> Ghent University
>> >> Faculty of Bioscience Engineering
>> >> Department of Mathematical Modelling, Statistics and Bio-Informatics
>> >>
>> >> tel : +32 (0)9 264 61 79
>> >> joris.m...@ugent.be
>> >> -------------------------------
>> >> Disclaimer : http://helpdesk.ugent.be/e-maildisclaimer.php
>> >>
>> >> [[alternative HTML version deleted]]
>> >>
>> >> ______________________________________________
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>> >
>> > ______________________________________________
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>>
>>
> --
> Joris Meys
> Statistical consultant
> Ghent University
> Faculty of Bioscience Engineering
> Department of Mathematical Modelling, Statistics and Bio-Informatics
> tel : +32 (0)9 264 61 79
> joris.m...@ugent.be
> -------------------------------
> Disclaimer : http://helpdesk.ugent.be/e-maildisclaimer.php
> [[alternative HTML version deleted]]
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