R devel - Oct 2009 - Improved Function Information with <TAB> Key

Hello,

Pressing the <TAB> key when typing a function into an R terminal does not
produce the expected output.  Currently, R will order all of the available
function inputs into alphabetical order and present them as options, whereas
it should display the inputs in the order they appear in the function.

For example:
> test = function(b,a,c){
print(b)
a*c
}
> test(   <TAB><TAB>
a=  b=  c
where <TAB> indicates pressing the Tab key.

It's easy to see that if the function were designed to accept 'b' as
a
string, and 'a' and 'c' as numerics that this function would
fail if the
user made the assumption that the <TAB> output is in the correct order,
and
input 'a' as a string.

This is a simple example, however I have several functions that I use often
and each has many possible inputs.  It would be useful to not have to
remember the order the inputs are in for each function, or have to use
args(function) beforehand.  It is also on occasion useful not to have to
explicitly name each input in your function.

Im using Ubuntu Linux 9.04 and a standard install of R 2.9.2 (unfortunately
not the polished R.app available on Macs - which coincidentally do display
function inputs in the correct order).

I welcome any thoughts, disagreements or tips any of you may have,

Thanks in advance,
    Lee Kelvin


-- 
Lee Kelvin
School of Physics & Astronomy
University of St Andrews
North Haugh
St Andrews KY16 9SS
United Kingdom

Phone (+44) [0]1334461668
Email lsk9@st-andrews.ac.uk

	[[alternative HTML version deleted]]

On Wed, Oct 7, 2009 at 5:56 AM, Lee Kelvin <lee.s.kelvin at gmail.com>
wrote:
> Hello,
>
> Pressing the <TAB> key when typing a function into an R terminal does
not
> produce the expected output. ?Currently, R will order all of the available
> function inputs into alphabetical order and present them as options,
whereas
> it should display the inputs in the order they appear in the function.
>
> For example:
>
>> test = function(b,a,c){
> print(b)
> a*c
> }
>
>> test( ? <TAB><TAB>
> a= ?b= ?c>
> where <TAB> indicates pressing the Tab key.
>
> It's easy to see that if the function were designed to accept
'b' as a
> string, and 'a' and 'c' as numerics that this function
would fail if the
> user made the assumption that the <TAB> output is in the correct
order, and
> input 'a' as a string.
>
> This is a simple example, however I have several functions that I use often
> and each has many possible inputs. ?It would be useful to not have to
> remember the order the inputs are in for each function, or have to use
> args(function) beforehand. ?It is also on occasion useful not to have to
> explicitly name each input in your function.
>
> Im using Ubuntu Linux 9.04 and a standard install of R 2.9.2 (unfortunately
> not the polished R.app available on Macs - which coincidentally do display
> function inputs in the correct order).
>
> I welcome any thoughts, disagreements or tips any of you may have,
The sorting is a feature of the readline library that is used as the
backend (there is no sorting on the Windows GUI). Apparently readline
6 allows you to inhibit sorting, so that might turn out to be useful.

-Deepayan