Ok, that's what I thought. Thanks! Hadley On Mon, Feb 18, 2013 at 12:43 PM, <luke-tier...@uiowa.edu> wrote: > 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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