[R] Can't there be a cd command?

[Duncan Murdoch]

On 5/10/2006 12:15 PM, Jan T. Kim wrote:
> On Wed, May 10, 2006 at 11:26:55AM -0400, Duncan Murdoch wrote:
>> On 5/10/2006 11:10 AM, Gabor Grothendieck wrote:
>> > On 5/10/06, Duncan Murdoch <murdoch at stats.uwo.ca> wrote:
> 
>> >> What is it that you find objectionable about having a default for the
>> >> file argument in read.table?  I think Martin has said that he doesn't
>> >> want non-UI functions to be involved with UI functions, but I don't see
>> >> that:  if your code works now, it will be completely unaffected by
>> >> setting a default for the argument.  (Sorry if I summarized the argument
>> >> incorrectly, Martin, I didn't look it up.)
>> > 
>> > That would be my objection too.  UI should not be tied to the non-UI core.
>> > Its basically a loose coupling argument.
>> 
>> I don't accept that argument, because in R everything* is interactive. 
>> There isn't a non-UI core.  The function arguments are part of the user 
>> interface.
> 
> It seems to me that there might be a misunderstanding here; as the term
> "user" is used to refer to a person interacting with the computer on
> the one hand, and to refer to a programmer using R on the other hand.

One of the design goals of S and R is to blur the distinction between 
users and programmers.  It is a continuum.  R is designed to gently urge 
non-programmers to become programmers, because the designers think 
that's the way statistical computing should be done.

> Everything being "part of the user interface", in the sense of
> every user-visible function being part of the API, does not and should
> not imply that everything should be interactive.

No, I didn't suggest that.  What I was suggesting is that it should be 
*convenient* to use read.table interactively, not that it should be 
required. (It's already possible, but not convenient, especially for a 
beginner who doesn't know the secret incantation.)

> In my experience, interactivity is a rather double-edged thing: On the
> one hand, it facilitates learning and exploration, but on the other
> hand, its improper use is frequently detrimental to reproducibility of
> scientific computation.

I definitely agree with that.  It should be convenient to use R 
non-interactively as well.  Anyone who wants reproducibility should be 
writing packages and scripts or vignettes that run non-interactively. 
That's why I am emphasizing that this change will have no effect on 
existing code.  I wouldn't suggest it if it did.

Duncan Murdoch