If statement generates two outputs

On Tue, 24 Mar 2009, Wacek Kusnierczyk wrote:

thanks.  so it seems to be intentionally parsable, though i wouldn't say
that this gives a meaning to ':=' -- the operator has a syntactic
category, but no semantics.  the syntactic category does not imply any
semantics, as in

   '<-' = function(a, b) NULL
   1 <- a
   # NULL

where '<-' is still parsed the original way (as a LEFT_ASSIGN, gram.y
again), but has now a completely different semantics.

it looks like a bug to me:  ':=' is parsed on par with '<-' as a
LEFT_ASSIGN, but apparently is not backed by any function.  it's a
zombie.  (unless rvalues is used, that is.)

yes, it's a zombie. It used to assign to the R system environment
rather than the global workspace (roughly what is the base namespace
now).