From murdoch at stats.uwo.ca  Mon Jun  6 22:57:37 2005
From: murdoch at stats.uwo.ca (Duncan Murdoch)
Date: Mon Jun  6 22:59:49 2005
Subject: [Rd] Bug in new() or validObject() in methods package (PR#7922)
In-Reply-To: <x2is0r8atn.fsf@turmalin.kubism.ku.dk>
References: <20050606200820.068F0A1C3@slim.kubism.ku.dk>
	<x2is0r8atn.fsf@turmalin.kubism.ku.dk>
Message-ID: <42A4B8C1.7060500@stats.uwo.ca>

On 6/6/2005 4:55 PM, Peter Dalgaard wrote:
> murdoch@stats.uwo.ca writes:
> 
>> Is it doing an extra eval or something?  It looks like it:
>> 
>>  > x <- expression()
>>  > x
>> expression()
>>  > eval(x)
>> NULL
>>  >
>>  > x <- quote(expression())
>>  > x
>> expression()
>>  > eval(x)
>> expression()
>>  > eval(eval(x))
>> NULL
> 
> You do realize that the two expression() results are not identical:
> 
>> x <- quote(expression())
>> class(x)
> [1] "call"
>> x <- expression()
>> class(x)
> [1] "expression"
> 
> Not that I can fathom what bearing that has on the real problem...

I figured they weren't identical, given that they gave different results 
  when eval'd, but I didn't know what the difference was exactly.  Thanks!

Duncan


[Rd] Bug in new() or validObject() in methods package (PR#7922)
Duncan Murdoch