[Rd] surprising behaviour of names<-

[Wacek Kusnierczyk]

Peter Dalgaard wrote:
>
> (*) unless you mess with match.call() or substitute() and the like. But
> that's a different story.
>   

different or not, it is a story that happens quite often -- too often,
perhaps -- to the degree that one may be tempted to say that the
semantics of argument passing in r is a mess. which of course is not
true, but since it is possible to mess with match.call & co, people
(including r core) do mess with them, and the result is obviously a
mess.  on top of the clear call-by-need semantics -- and on the surface,
you cannot tell how the arguments of a function will be taken (by
value?  by reference?  not at all?), which in effect looks like a messy
semantics.

vQ