[Rd] should the text for RIGHT_ASSIGN be -> in getParseData()?

[peter dalgaard]

On Jul 5, 2013, at 18:59 , William Dunlap wrote:

>> Is there any reason right-assign with "->" still exists? How much
>> code on CRAN uses it, and how trivially could it be excised?
> 
> I use '->' a lot when doing interactive work.  I often first run a command
> to see its printed output then decide that I had better save its value.
> The up-arrow key gives me the previous command line with the cursor placed at the
> end of the line so adding '-> z' at the end of the line is convenient.
> (Not using the up-arrow key and doing 'z <- .Last.value' also works, but
> I don't like its context sensitivity.)

But up-arrow, ctrl-A then "z <-" is not much less convenient, is it? 

I have used in with multi-line input, occasionally, though. As in

replicate(10000, {
   ysim <- rbinom(length(p), n, p)
   glm(cbind(ysim, n - ysim) ~ x, binomial)$deviance 
})

... and then you realize that you probably don't want to look at 10000 simulated deviances and add "-> simDev". 

> 
> I never use '->' when writing code in a file, so you would have to search
> my .Rhistory files, not my *.R files, for evidence of its usefulness to me.
> 
> Bill Dunlap
> Spotfire, TIBCO Software
> wdunlap tibco.com
> 
> 
>> -----Original Message-----
>> From: r-devel-bounces at r-project.org [mailto:r-devel-bounces at r-project.org] On Behalf
>> Of Barry Rowlingson
>> Sent: Friday, July 05, 2013 9:29 AM
>> To: Duncan Murdoch
>> Cc: R-devel
>> Subject: Re: [Rd] should the text for RIGHT_ASSIGN be -> in getParseData()?
>> 
>> On Fri, Jul 5, 2013 at 12:57 PM, Duncan Murdoch
>> <murdoch.duncan at gmail.com> wrote:
>> 
>>> R itself doesn't make use of the text column, it's for display of code
>>> by highlighters etc.  So if anyone does assume text is a function name,
>>> it's their bug, not ours.  In fact, the bug is already there, because
>>> there is actually one other example which was being parsed properly,
>>> "**" is translated to "^".  There's no `**` function, but 2**3 works.
>> 
>> Is there any reason right-assign with "->" still exists? How much
>> code on CRAN uses it, and how trivially could it be excised? Can we
>> also have 'up assign'  and "down assign" so I can do:
>> 
>>>    3
>>> x -^
>>> x -v
>>>    4
>> 
>> - they make just as much sense.
>> 
>> Okay, lets see all the edge cases.....
>> 
>> Barry
>> 
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> 
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-- 
Peter Dalgaard, Professor,
Center for Statistics, Copenhagen Business School
Solbjerg Plads 3, 2000 Frederiksberg, Denmark
Phone: (+45)38153501
Email: pd.mes at cbs.dk  Priv: PDalgd at gmail.com