[R] lines don't wrap. must scroll horizontally to see/edit a long line in R GUI

[Duncan Murdoch]

On 13/12/2009 5:22 PM, Carl Witthoft wrote:
> Duncan Murdoch wrote:
>   "This is by design.  Carriage returns have syntactic meaning in R, so the
> editor shouldn't display phantom ones.  In Linux there's no choice
> because R doesn't control how text is displayed, but the Windows GUI
> gets it right."
> 
> 
> I have to disagree here.  Soft-wrapping is the default option in most 
> editors, and the OSX R.app gui wraps both input and output.  It's pretty 
> easy to tell a bunch of code is (or isn't) all one line unless you don't 
> believe in prompts or something :-).

Try this in the OSX GUI (or any other editor that does soft wrapping).

Open a "New Document", and make the window pretty narrow, e.g. about 
10-20 chars wide.  (You can make it wider, but you'll have more typing 
below.)

Type this line into it, with enough ones that it wraps to 3 lines:

x <- 111111111111111

It will look something like this in the GUI.

x <-
11111111111111
1

Other editors might wrap differently, e.g. vi pays no attention to 
whitespace, and just wraps the characters when it hits the end of the line.

Now put a hard return before the 1 on the third line.  It will look 
almost identical, but (in the GUI editor) you'll see that the third line 
now has a line number 2.  It's a bit hard to see, but I wouldn't complain.

Now copy and paste the whole thing into the console.  If the console is 
also narrow enough, it will look the way I've typed it above, with 
nothing at all to signal it's really two lines, not 1 or 3, until you 
hit enter to execute both lines.

This is fine in languages like C where newlines barely matter, but it 
makes a big difference whether that's one line or two in R.

So I'd say the best practice is to keep your lines short enough that you 
never have your editor wrapping things for you, and to use editors that 
give strong visual signals (e.g. the Windows GUI's $ signs, or the OSX 
GUI editor's line numbering) when you accidentally violate this rule.

Duncan Murdoch