We have long been discouraging the use of pairlists. So no, we will not do anything to facilitate this conversion; if anything the opposite. SET_TYPEOF is used more than it should be in the sources. It is something I would like us to fix sometime, but isn't high priority.
Best, luke On Fri, 5 Jul 2024, Kevin Ushey wrote:
Hi, A common idiom in the R sources is to convert objects between LANGSXP and LISTSXP by using SET_TYPEOF. However, this is soon going to be disallowed in packages. From what I can see, there isn't currently a direct way to convert between these two object types using the available API. At the R level, one can convert calls to pairlists with:as.call(pairlist(as.symbol("rnorm"), 42))rnorm(42) However, the reverse is not possible:as.pairlist(call("rnorm", 42))Error in as.pairlist(call("rnorm", 42)) : 'language' object cannot be coerced to type 'pairlist' One can do such a conversion via conversion to e.g. an intermediate R list (VECSXP), but that seems wasteful. Would it make sense to permit this coercion? Or, is there some other relevant API I'm missing? For completeness, Rf_coerceVector() also emits the same error above since it uses the same code path. Thanks, Kevin ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
-- Luke Tierney 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/ ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
