Gabor Grothendieck wrote: > On Wed, Jan 28, 2009 at 6:26 AM, Wacek Kusnierczyk > <waclaw.marcin.kusnierc...@idi.ntnu.no> wrote: > >> Gabor Grothendieck wrote: >> >>> The argument to eval.parent is evaluated before eval.parent >>> ever sees it. >>> >> really? eval.parent is just a regular r function, a wrapper for eval >> with envir=parent.frame(). the arguments to eval.parent are passed to >> eval *unevaluated* (as promises), and are only evaluated when eval needs >> them. here's a modified eval.parent: >> > > Yes, you're right about the mechanism although quoting the > help page its nevertheless true that it: > "evaluates its first argument in the current scope before > passing it to the evaluator" > ... where 'current scope' is as clear as the sky over trondheim right now [1], the issue being:
- is 'current scope' the scope in which eval (the above quote refers to eval) is called (as it seems to be meant), or - the scope *within* the call to eval (which would be intuitively obvious, since when eval 'evaluates' it must have already been entered and not yet left, so we're inside the eval-call scope). another example of how quoting an r help page helps provided you already know the answer. must admit that 'eval evaluates its argument before passing it to the evaluator' is quite funny a quote; so eval is able to evaluate without an evaluator? magic! *what* is it that is true, quoting the help page? vQ [1] http://www.yr.no/place/Norway/S%C3%B8r-Tr%C3%B8ndelag/Trondheim/Trondheim/ ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
