When dealing with object holding pointers that are only valid during a single session, it would be convenient to exclude them from being saved with the session image. (I am assuming that `quit` calls `save.image` before quitting or is it internal?) Currently they are saved with the pointer converted to NULL. Its a bit surprising for users not realizing the object is no longer valid.
My thought is to designate a class name (perhaps "no.save") and exclude anything that inherits from that. I've hacked a quick implementation below. I did not issue a warning, but it would be a simple fix. Does anyone else see this as useful? THK -- http://www.keittlab.org/ .new.save.image = function (file = ".RData", version = NULL, ascii = FALSE, compress = !ascii, safe = TRUE, omit.no.save = TRUE) # added "omit.no.save" argument { if (!is.character(file) || file == "") stop("'file' must be non-empty string") opts <- getOption("save.image.defaults") if (is.null(opts)) opts <- getOption("save.defaults") if (missing(safe) && !is.null(opts$safe)) safe <- opts$safe if (missing(ascii) && !is.null(opts$ascii)) ascii <- opts$ascii if (missing(compress) && !is.null(opts$compress)) compress <- opts$compress if (missing(version)) version <- opts$version if (safe) { outfile <- paste0(file, "Tmp") i <- 0 while (file.exists(outfile)) { i <- i + 1 outfile <- paste0(file, "Tmp", i) } } else outfile <- file on.exit(file.remove(outfile)) ### Omit objects inheriting from "no.save" ### objns <- ls(envir = .GlobalEnv, all.names = TRUE) if ( omit.no.save ) ### make part of options? objns <- subset(objns, sapply(objns, function(x) { ! inherits(get(x, envir = .GlobalEnv), "no.save") })) save(list = objns, file = outfile, version = version, ascii = ascii, compress = compress, envir = .GlobalEnv, precheck = FALSE) ### End code changes ### if (safe) if (!file.rename(outfile, file)) { on.exit() stop(gettextf("image could not be renamed and is left in %s", outfile), domain = NA) } on.exit() } setClass("no.save") setClass("test.class", slots = c(s1 = "externalptr")) setIs("test.class", "no.save") reg.obj = "regular object" no.save.obj = new("test.class") .image.file = tempfile() save.image(.image.file) rm(reg.obj, no.save.obj) load(.image.file) print(ls()) unlink(.image.file) .new.save.image(.image.file) rm(reg.obj, no.save.obj) load(.image.file) print(ls()) unlink(.image.file) [[alternative HTML version deleted]] ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
