[plt-scheme] Does `(a,b'c) follow r6rs formal grammar?

Then is it a bug in plt scheme that this is accepted?

#!r6rs
(import (rnrs))
(define b 4)
(display `(a,b'c))

Using drscheme, the module language, and entering above into definitions 
window.

On Sunday 28 June 2009 02:06:59 am Abdulaziz Ghuloum wrote:
> On Jun 27, 2009, at 8:36 PM, Jon Stenerson wrote:
> > Is the expression `(a,b'c)  lexically valid according to r6rs? It says
> > (section 4.2) that identifiers must be terminated by a delimiter or
> > end of
> > input, but this is not true for the identifiers a and b since
> > neither the
> > comma nor quote are listed as delimiters.
>
> You gave the question and the answer.
>
> Aziz,,,