[Rd] as.environment.list provides inconsistent results under torture

luke-tierney at uiowa.edu luke-tierney at uiowa.edu
Wed Jan 12 15:45:33 CET 2011

On Wed, 12 Jan 2011, peter dalgaard wrote:

> On Jan 12, 2011, at 14:18 , <luke-tierney at uiowa.edu> <luke-tierney at uiowa.edu> wrote:
>> I did do a quick scan of R-devel for this issue with eval and found these:
>>    ./unix/aqua.c:	     eval(LCONS(install("library"),CONS(install("grDevices"),R_NilValue)),R_GlobalEnv);
>>    ./unix/sys-std.c:    infile = PROTECT(eval(lang1(RComp_getFileCompSym), rcompgen_rho));
>>    ./modules/X11/dataentry.c:       newval <- eval(parse(text=newval))
>>    ./main/envir.c:			 return(eval(lang4(install("list2env"), arg,
>>    ./gnuwin32/dataentry.c:       newval <- eval(parse(text=newval))
>> I'll fix them in the next couple of days if no one else gets there
>> first (but I'm not set up to test the aqua or gnuwin32 ones).
> You had me perplexed there for a while: "<-" assignment in C code??? However, those lines occur inside comments, so at least gnuwin32 is not to worry about.

:-) I guess I would have noticed that when I started trying to fix things ...

> As you look around those parts, you might also find some superfluous PROTECTs inserted by me some time in the last century while trying to chase down the mysterious crashes that we had. (They eventually turned out to be caused by parser lookahead breaking protection stack discipline, fixed by UNPROTECT_PTR() etc.). I lost track a bit in the frenzy and I never got around to backing out everything.

I think for now the "if it ain't broke don't fix it" principle applies
to those, unless you have spare time on your hands ...



Luke Tierney
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 at stat.uiowa.edu
Iowa City, IA 52242                 WWW:  http://www.stat.uiowa.edu

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