[R-SIG-Mac] Assignment arrow

Seth Falcon sfalcon at fhcrc.org
Wed Feb 28 20:16:41 CET 2007

Simon Urbanek <simon.urbanek at r-project.org> writes:

> John,
> On Feb 10, 2007, at 6:25 PM, John Shonder wrote:
>> To use R on my Mac, I had been running ESS in emacs under X11. I  
>> found R.app, and much prefer it -- especially the quartz graphics  
>> -- but there's one thing I miss about ESS: to get an assignment  
>> arrow "<-" you just type shift underscore. In R.app, you have to  
>> type the less than sign (shift-comma) followed by the dash. Coming  
>> over from ESS, the extra keystroke bothers me.
> To be honest IMHO it's one of the annoying "features" in ESS  
> (configurable, though, I presume), because "_" is a valid character  
> used in names, so you end up getting broken code like .Platform$r <-  
> arch instead of the intended .Platform$r_arch when copy/pasting code.  
> In old times it was legal to use _ instead of <-, so ESS was helping  
> to make your code more legible without changing the syntax (a_10 was  
> the same as a <- 10), but that is not true anymore.

I agree about the default setting in ESS being annoying.  I have the
following in my .emacs:

    ;; leave my underscore key alone!
    (ess-toggle-underscore nil)
    (setq ess-S-assign-key [?\C-=])

This way, <_> is itself and <ctrl>+<=> gives <- and <=> gives =.

+ seth

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