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Re: draft-duerst-iri-07.txt: 2 week mailing list last call (IRIsyntax-28)

From: Graham Klyne <gk@ninebynine.org>
Date: Wed, 12 May 2004 10:37:23 +0100
Message-Id: <5.1.0.14.2.20040512102732.02bf4b80@127.0.0.1>
To: Martin Duerst <duerst@w3.org>, public-iri@w3.org
Cc: uri@w3.org

Martin,

Thanks for your response.  Where you say:
[[
I think what you mean is to only change some terminal productions,
but leave the rest unchanged. There are several reasons why this
hasn't been done:
]]
This was roughly what I had in mind, but I can see why you prefer not to do 
this.  This is primarily a matter of preference and perspective, and I am 
content to accept your decision.  Your point about URI vs IRI is well-made.

Simply adding a brief descriptive paragraph capturing the thrust of this:
[[
- In the most general sense, it would have been okay to just
   add ucschar to unreserved. But there is the issue of allowing
   private characters in query parts, but not elsewhere.
]]
in the introduction to the section about the grammar would have helped me 
to see quickly where the changes were; e.g.
[[
The following grammar closely follows the URI grammar in [RFC2396bis], 
except that the range of unreserved characters is expanded to include UCS 
characters, with the restriction that private UCS characters can occur only 
in query parts and not elsewhere.
]]

#g
--

At 10:02 12/05/04 +0900, Martin Duerst wrote:
>Hello Graham,
>
>Many thanks for your comments. I'm responding in pieces,
>as I split things up into issues. This is issue
>http://www.w3.org/International/iri-edit/#IRIsyntax-28
>
>At 12:02 04/05/10 +0100, Graham Klyne wrote:
>
>>Martin,
>>
>>These comments are based on a quick skim rather than a detailed reading.
>>
>>Looking at this from an implementer's perspective, I feel it would be 
>>helpful if the relationship between the IRI and URI *grammars* were more 
>>clearly delineated;  e.g. a presentation of IRI syntax that is based on 
>>the RFC2396bis grammar,
>
>It definitely is. I have very carefully followed all the changes
>in the RFC2396bis grammar. I very much hope I got it right, but
>any additional crosschecks would be greatly appreciated.
>
>
>>replacing a minimum number of productions.
>
>I think that's also the case.
>
>I think what you mean is to only change some terminal productions,
>but leave the rest unchanged. There are several reasons why this
>hasn't been done:
>
>- In the most general sense, it would have been okay to just
>   add ucschar to unreserved. But there is the issue of allowing
>   private characters in query parts, but not elsewhere.
>- Looking top down, what you seem to want may actually imply
>   to use 'URI' rather than 'IRI' at the start of the grammar.
>   I think that would have been more confusing than helpful.
>   And once you start making these distinctions, it would
>   then again be confusing to e.g. use 'path' rather than
>   'ipath'.
>- The current solution allows to very easily create a combined
>   grammar of URIs and IRIs, which some people might want to do.
>   If the two grammars would use the same symbols for things that
>   are on  purpose the same, but in actual syntax are different,
>   that wouldn't work.
>- The grammar allows somebody who wants to only implement IRIs
>   to do that directly. It may lead to less implementation
>   divergence than a verbal description of differences against
>   another spec.
>
>
>>On this basis, it would be easier to see what needs to be changed in a 
>>URI parser to yield an IRI parser.
>
>I hope it's already easy enough to see. I have used very
>straightforward naming conventions to correlate the corresponding
>nonterminals in both grammars. If there is 'URI' in the original
>nonterminal, I have changed that to 'IRI'. Otherwise, I have
>prefixed an 'i'. If you think this is helpful, I can add a
>sentence to that effect.
>
>
>>Also, I note that the RFC2396bis grammar has been through several 
>>revisions as subtle issues are exposed by review and implementation 
>>experience;  by replicating the entire grammar (rather than saying that 
>>an IRI is like a URI with designated changes), can you be confident that 
>>such issues have not been re-introduced?
>
>Of course, there is never any absolute confidence, but as far as
>I remember, these issues were all related to details around
>special cases such as e.g. empty paths. They are therefore
>orthogonal to the issue of extending the repertoire of
>'reserved' characters. One might be able to immagine some
>interactions if e.g. authorities and paths were extended
>in a different way, but the difference is for query parts,
>which are very clearly delineated, and haven't been at
>issue in the bugs you mention above.
>
>I hope you are satisfied with this answer. If not, I would
>appreciate a more detailled proposal.
>
>
>Regards,   Martin.

------------
Graham Klyne
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Received on Wednesday, 12 May 2004 06:08:37 UTC

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