Stavros Macrakis wrote: > Tested in: R version 2.8.1 (2008-12-22) / Windows > > Recursive default argument references normally give nice clear errors. > In the first set of examples, you get the error: > > Error in ... : > promise already under evaluation: recursive default argument > reference or earlier problems? > > (function(a = a) a ) () > (function(a = a) c(a) ) () > (function(a = a) a[1] ) () > (function(a = a) a[[1]] ) () > (function(a = a) a$x ) () > (function(a = a) mean(a) ) () > (function(a = a) sort(a) ) () > (function(a = a) as.list(a) ) () > > But in the following examples, R seems not to detect the 'promise > already under evaluation' condition and instead gets a stack overflow, > with the error message: > > Error: C stack usage is too close to the limit >
when i run these examples, the execution seems to get into an endless loop with no error messages whatsoever. how much time does it take before you get the error? (using r 2.8.0 and also the latest r-devel). vQ > (function(a = a) (a) ) () > (function(a = a) -a ) () > btw. ?'-' talks about '-' as a *binary* operator, but the only example given there which uses '-' uses it as a *unary* operator. since '-'() complains that '-' takes 1 or 2 arguments, it might be a good idea to acknowledge it in the man page. > (function(a = a) var(a) ) () > (function(a = a) sum(a) ) () > (function(a = a) is.vector(a) ) () > (function(a = a) as.numeric(a) ) () > > I don't understand why the two sets of examples behave differently. > a bug in excel? vQ ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
