Dear list, This probably makes perfect sense from the language designers' perspective, but at least for me this was/is quite an interesting and unexpected behavior which I thought might be worth sharing:
The default value of argument |where|in function |getClasses()|seems to vary depending on whether |getClasses()|is called inside a *standard R function*or a *formal S4 method*. It is controlled by |.externalCallerEnv()|, which seems to be "vulnerable" to /lazy evaluation/and/or an "altered" /lexical scoping/structure (possible introduced by the definition of a formals S4 method?) and thus causes the variation**. I found it quite hard to understand what's exactly going on as you need to manually debug `getClasses()` in order to find out what the default value of `where` (controlled by `|.externalCallerEnv()`) actually is in the various settings|. But that of course might as well be just me ;-) For those interested, I tried to illustrate the behavior in this SO post: http://stackoverflow.com/questions/12166645/ambiguous-variation-of-default-environment-in-getclasses-standard-function/12174390#12174390 Best regards, Janko Thyson [[alternative HTML version deleted]] ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
