Prof Brian Ripley <[EMAIL PROTECTED]> writes: > There is already a bug report PR#4364 on an aspect of this. The comment > there is > > dump somehow needs to recognize that expressions in lists > probably need to be enclosed in quote(). > > S does exactly the same though > > (I think it is a symbol not a formal expression in the current examples.)
The comment and the report are both a little unclear. Objects of mode "expression" are not the issue, since they do deparse/eval correctly. Symbols and calls are. > I believe it is rather difficult to determine what we cannot deparse > successfully, and trying to issue a warning/error would give a false sense > of security. The code (src/main/deparse.c) suggests that at least > > promises > environments > external pointers > weak references > > will not get a useful textual representation. I don't think the goal can > be as Peter describes -- it has to be more limited, and currently symbols > are also on the list. Yes, I know. I didn't mean a goal in the sense that it can always be achieved. Promises can be forced, but the other types are not easy to handle.(I don't think even save/load knows what to do with external pointers.) > (We might be able to solve symbols, but it is far > from straightforward -- terms in formulae are symbols, for example, so we > cannot just add quote() around symbols and that does indeed break code.) Hmm, I thought the issue was that we need to quote calls but cannot quote formulas (which are calls). > There may well be others: it was not so long ago that integer vectors were > dumped in a text representation that was read back in as numeric. ...so that we now have dput() output with as.integer() constructs all over the place. (Can't have and eat, etc., I know.) -- O__ ---- Peter Dalgaard Blegdamsvej 3 c/ /'_ --- Dept. of Biostatistics 2200 Cph. N (*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918 ~~~~~~~~~~ - ([EMAIL PROTECTED]) FAX: (+45) 35327907 ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html