macra...@alum.mit.edu wrote: > nchar(with(list(2),ls())) gives an internal error. This is of course > a peculiar call (no names in the list), but the error is not caught > cleanly. > > It is not clear from the documentation whether with(list(2)...) is > allowable; if it is not, it should presumably give an error. If it is, then > ls > shouldn't have problems with the resulting environment. > >> qq <- with(list(2),ls()) # An incorrect call (no > names in list) >> nchar(qq) > Error in nchar(qq) : 'getEncChar' must be called on a CHARSXP # ls returned > a bad object >> qq > [1]Error: 'getEncChar' must be called on a CHARSXP >> qq[1] > [1]Error: 'getEncChar' must be called on a CHARSXP >> qq[2] > [1] NA > > Apparently related: > >> with(list(a=1,2),ls()) > Error in ls() : 'getEncChar' must be called on a CHARSXP
Thanks, yes, this looks wrong. Also, closer to the root cause: > eval(quote(ls()),list(a=1,2)) Error in ls() : 'getEncChar' must be called on a CHARSXP > e <- evalq(environment(),list(2)) > ls(e) [1]Error: 'getEncChar' must be called on a CHARSXP It is not quite clear that it should be allowed to have unnamed elements in lists used by eval (which is what with() uses internally). I suppose it should, since the intended semantics are unaffected in most cases. (I.e., there is nothing really wrong with eval(quote(a+b), list(a=1,b=2,3,4)), and people may have been using such code unwittingly all over.) However, it IS a bug that we are creating ill-formed environments. The culprit seems to be that NewEnvironment (memory.c) is getting called in violation of its assumption that " This definition allows the namelist argument to be shorter than the valuelist; in this case the remaining values must be named already. (This is useful in cases where the entire valuelist is already named--namelist can then be R_NilValue.) " Removing the assumption from NewEnvironment looks like an efficiency sink, so I would suggest that we fix do_eval (eval.c) instead, effectively doing l <- l[names(l) != ""]. So in case LISTSXP: env = NewEnvironment(R_NilValue, duplicate(CADR(args)), encl); PROTECT(env); break; we need to replace the duplicate() call with something that skips the unnamed elements. The only side effect I can see from such a change is the resulting environments get a different length() than before. I'd say that if there are coder who actually rely on the length of an invalid environment, then they'd deserve what they'd get... -- O__ ---- Peter Dalgaard Ă˜ster Farimagsgade 5, Entr.B c/ /'_ --- Dept. of Biostatistics PO Box 2099, 1014 Cph. K (*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918 ~~~~~~~~~~ - (p.dalga...@biostat.ku.dk) FAX: (+45) 35327907 ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel