Re: [art] Fwd: New Version Notification for draft-rivest-sexp-06.txt

[Erik Auerswald <[e-mail]>]

Hi,

On Wed, Apr 17, 2024 at 01:02:54AM -0400, Donald Eastlake wrote:
> 
> An improved version has been posted responding to many of the comments
> that have been made.

Thanks for the update!

I'd like to make a few comments from a quick glance:

1. It seems to me as if the second example of an S-expression given in
   section 6.1 does not match the ABNF given in section 7.1.

2. It seems to me as if the "canonical" representation is not uniquely
   defined, because -- according to the examples -- it may use "display
   hints", but it is not specified if the "default" display hint
   ("application/octet-stream" in the current draft) may be given or not.

3. Since the "default" display hint may be application-specific, omitting
   it from the "canonical" representation, as shown in two of the three
   examples in section 6.1, seems to possibly change the "canonical"
   S-expression value when changing applications.

4. The value of the "default" display hint has changed over the versions
   of this draft.  I'd expect this to cause interoperability problems
   if any new implementation were to emerge, and if any existing
   implementation would already implement the original default display
   hint.

5. I'd say that this S-expression format has no similarities to
   Bernstein's "netstrings", i.e., the length of a general S-expression
   is not given up front.  Giving the complete length up front is the
   one special property provided by netstrings.  Thus I'd say that the
   last sentence of the first paragraph of section 1.1 is misleading.

Best regards,
Erik