From gmbecker at ucdavis.edu  Thu Oct 22 23:08:37 2015
From: gmbecker at ucdavis.edu (Gabriel Becker)
Date: Thu, 22 Oct 2015 14:08:37 -0700
Subject: [Rd] Changed behaviour when passing a function?
In-Reply-To: <CAO1zAVb9azyYRR-fu5EKwzv0h9Rhu_tuL6oVtbyA1rW_5hAnFw@mail.gmail.com>
References: <CAO1zAVb9azyYRR-fu5EKwzv0h9Rhu_tuL6oVtbyA1rW_5hAnFw@mail.gmail.com>
Message-ID: <CADwqtCNPb0wxhkZG+dR9r6nvhd2W70R+0VbJ7iucfcCNN3N7MA@mail.gmail.com>

Joris,


When a function call (detected via the parenthesis) R does the equivalent
of get(..., mode="function") to resolve the symbol.

> round = 2
> round(5.3)
[1] 5
> get("round")
[1] 2
> get("round", mode = "function")
function (x, digits = 0)  .Primitive("round")


It's done this for a while, but didn't always do it, I think. I don't know
when the change happened.

Best,
~G


On Thu, Oct 22, 2015 at 10:59 AM, Joris Meys <jorismeys at gmail.com> wrote:

> Hi all,
>
> When teaching this year's class, I was quite amazed that one of my examples
> didn't work any longer. I wanted to illustrate the importance of
> match.fun() with following code:
>
> myfun <- function(x, FUN, ...){
>     FUN(x, ...)
> }
> round <- 2
> myfun(0.85, FUN = round, digits=1)
>
> I expected to see an error, but this code doesn't generate one. It seems as
> if in the current R version match.fun() is added automatically.
>
> I've scrolled through the complete R News section specifying all the
> changes and bug fixes, starting from 3.0.0.  I couldn't find anything on
> that change in behaviour though. Where can I find more information on what
> changed exactly?
>
> Thanks
> 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.Meys at Ugent.be
> -------------------------------
> Disclaimer : http://helpdesk.ugent.be/e-maildisclaimer.php
>
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>
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>



-- 
Gabriel Becker, PhD
Associate Scientist (Bioinformatics)
Genentech Research

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[Rd] Changed behaviour when passing a function?
Gabriel Becker