Hello,

and sorry if this is already explained somewhere. I couldn't find anything.

R (2.3.1, Windows) seems to perform some kind of lazy evaluation when
evaluating defaults in function calls that, at least for me, leads to
unexpected results. Consider the following, seemingly equivalent functions:

> foo1 <- function(x, y=x) {
+  x <- 0
+  y
+ }
> foo1(1)
[1] 0
> foo2 <- function(x, y=x) {
+  y <- y
+  x <- 0
+  y
+ }
> foo2(1)
[1] 1

Obviously, y is not evaluated until it is used in some way. I would
expect it to be evaluated where it is defined. Is this intended behavior?
Thanks for clarifying,

Uli

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