[R] 'text' can't find "x"
tlumley at u.washington.edu
Thu Oct 17 19:45:50 CEST 2002
On Thu, 17 Oct 2002, [iso-8859-1] Göran Broström wrote:
> With the default value of 'labels':
> > text(x = c(1, 2), y = 5, labels = seq(along = x))
> Error in seq(along = x) : Object "x" not found
> A scoping bug? :)
> > text(x = c(1, 2), y = 5)
> is OK. Doesn't give the labels I want, though. But why does it work, i.e.,
> why is 'x' found in this case and not when I write out the default?
Explicit arguments are evaluated in the calling environment and the value
is passed to the function. Default arguments are evaluated inside the
function, so that defaults like seq(along=x) work.
Evaluating explicit arguments inside the function would be a Really Bad
Idea, as you would need to know what variables existed inside the
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