On Wed, 2003-11-05 at 12:06, Prof Brian Ripley wrote: > A list is just a vector of type VECSXP. > There IS a section called `Handling lists'. > > I don't think the gap is in the `Writing R Extensions' document, maybe in > your reading of it. > That section discusses reading lists, not making them.
It also includes no explicit statement that the names of list items are in the R_NamesSymbol attribute, nor instructions on how to create the value that goes in that attribute (i.e., it should be a character vector and its elements made with mkChar()). (I'm also not sure how deep one needs to use PROTECT, though that's a more general issue.) There is no explicit statement that the elements of the list are arbitrary SEXP's. I also had the list[i] vs list[[i]] lurking in my mind, wondering how that mapped to the C level constructs. That is less central. I'm not saying the clues aren't there; after all, I did work it out, I think correctly. I am saying that certain information would be better stated explicitly rather than simply being open to inference from an example. And I am saying that an explicit example of constructing and returning a list (with named members) would be useful, since that's a common scenario. > On Wed, 5 Nov 2003, Ross Boylan wrote: > > > I thought there were some gaps in the R Extensions document; in > > particular, I was left wondering how to create a list. I think a > > paragraph on it would be useful. > > > > I would be happy to contribute the paragraph, but I'm not sure if > > there's interest or what the procedure is. Can anyone advise me? > > > > Though I was looking at the 1.7.0 version, I just checked 1.8.0 and the > > relevant section seems the same. > > > > My ulterior motive is to discover if my understanding of lists is > > actually correct :) > > -- Ross Boylan wk: (415) 502-4031 530 Parnassus Avenue (Library) rm 115-4 [EMAIL PROTECTED] Dept of Epidemiology and Biostatistics fax: (415) 476-9856 University of California, San Francisco San Francisco, CA 94143-0840 hm: (415) 550-1062 ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help
