From maechler at stat.math.ethz.ch  Thu Jul 20 17:36:50 2017
From: maechler at stat.math.ethz.ch (Martin Maechler)
Date: Thu, 20 Jul 2017 17:36:50 +0200
Subject: [Rd] Change in print.function between R 3.4.1 and R 3.4.0
In-Reply-To: <CACsp0uJMjDL-JjiWQN24XVtS2REwEbmR7h-h0eAWv+DrkF1QdA@mail.gmail.com>
References: <CACsp0uJMjDL-JjiWQN24XVtS2REwEbmR7h-h0eAWv+DrkF1QdA@mail.gmail.com>
Message-ID: <22896.52754.12907.448687@stat.math.ethz.ch>

>>>>> nicola farina <farinan at gmail.com>
>>>>>     on Thu, 20 Jul 2017 16:51:54 +0200 writes:

    > Dear all,
    > I just installed R 3.4.1 and noticed a change in how user-defined functions
    > are printed. A small example:

    > string<-"f<-function(x){\n\tx^2\n}"
    > cat(string,file="tmp00a.R")
    > source("tmp00a.R")
    > f

    > And this is what I see:

    > #R 3.4.0
    > function(x){
    > x^2
    > }

    > #R 3.4.1
    > function(x){
    > \tx^2
    > }

    > Seems that in 3.4.1 the tab character isn't "rendered". This is rather
    > annoying since it becomes very difficult to inspect the source code of user
    > defined functions. This behaviour seems to be present just for the tab
    > character (\n and \r are displayed correctly).

    [..............]

    > Thank you for your attention and your incredible work.

Thank you for the flowers.

Believe it or not, I've detected this bug about 8 hours ago, after typing

  menu

at the R prompt after receiving a bug report about it.

It came from fixing bug  PR#16732  (which was about rendering
Japanese fonts in a function defintion when printing)

  https://bugs.r-project.org/bugzilla/show_bug.cgi?id=16732

A (probably shortest possible!) symptom of the bug is
that in R <= 3.4.0,

> quote(-"\n")
-"\n"
> 

whereas in R 3.4.1 (and the current newer development versions of R)

> quote(-"\n")
-"\\n"
> 


Ideally, fixing this (wrong duplication of "\") will not make
bug 16732 resurface.

I expect a bug fix by tomorrow.
If this is a big problem for you, you will have to upgrade to
     "R 3.4.1 patched"
during the weekend.
(Downgrading to R 3.4.0 is not a good idea, compared to the above!)

Martin Maechler,
ETH Zurich


    > Nicola Farina

    > [[alternative HTML version deleted]]
     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    (do learn to post in plain text on R-devel, please)



[Rd] Change in print.function between R 3.4.1 and R 3.4.0
Martin Maechler