Of course not. What I hope can happpen is that we can reduce the
degree to which internal implementation quirks leak out into the user
level. The fact that there is an internal "missing token" (that
happens to be used for a couple of different things) is a quirk; if
you look at the code I use you can see why it is a quirk. Cleaning
this up will help computing on the language (at least that is the
hope).
luke
On Mon, 18 Feb 2013, Hadley Wickham wrote:
In general, should we expect that the ability to compute on the
language within R will decrease over time? Otherwise, I presume if you
do change the behaviour of missing then you'll still provide some way
to create/call functions with missing arguments.
Hadley
On Mon, Feb 18, 2013 at 12:31 PM, <luke-tier...@uiowa.edu> wrote:
I wouldn't count on any way of capturing this thing being reliable in
the long term. As I recall what I do in codetools and the compiler is
use features of missing() to test for it, but try to abstract those
uses into one or two places only so I can easily change them if
missing()'s behavior changes. Basically this internal thing
_shouldn't_ be visible at R level, and if we ever figure out how to
make that happen it will.
Best,
luke
On Mon, 18 Feb 2013, Hadley Wickham wrote:
Hi all,
I think there's a small buglet in quote:
str(quote())
# Error in quote() : 0 arguments passed to 'quote' which requires 1
str(quote(expr = ))
# symbol
I bring this up because this seems like the most natural way of
capturing the "missing" symbol with pure R code, compared to
substitute() or bquote() or formals(plot)$x
Hadley
--
Luke Tierney
Chair, Statistics and Actuarial Science
Ralph E. Wareham Professor of Mathematical Sciences
University of Iowa Phone: 319-335-3386
Department of Statistics and Fax: 319-335-3017
Actuarial Science
241 Schaeffer Hall email: luke-tier...@uiowa.edu
Iowa City, IA 52242 WWW: http://www.stat.uiowa.edu
--
Luke Tierney
Chair, Statistics and Actuarial Science
Ralph E. Wareham Professor of Mathematical Sciences
University of Iowa Phone: 319-335-3386
Department of Statistics and Fax: 319-335-3017
Actuarial Science
241 Schaeffer Hall email: luke-tier...@uiowa.edu
Iowa City, IA 52242 WWW: http://www.stat.uiowa.edu
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