[Rd] Eval and the enclos argument

[Duncan Murdoch]

On 02/10/2010 10:40 AM, Hadley Wickham wrote:
> On Sat, Oct 2, 2010 at 8:18 AM, Duncan Murdoch <murdoch.duncan at gmail.com> wrote:
>> On 02/10/2010 7:57 AM, Hadley Wickham wrote:
>>> Hi all,
>>>
>>> I'm trying to understand the default value of the enclos argument of eval:
>>>
>>>  enclos = if(is.list(envir) || is.pairlist(envir)) parent.frame()
>>> else baseenv()
>>>
>>> Why isn't it just
>>>
>>>  enclos = parent.frame()
>>>
>>> given that enclos is only meaningful (given my reading of the
>>> documentation) when envir is not an environment already.
>>>
>>> Hadley
>>>
>>
>> I think that handles the case of envir=NULL.
> 
> So that makes eval(expr, NULL) equivalent to eval(expr, baseenv()), right?

I think so.

Duncan