Re: [Iptel] [Editorial Errata Reported] RFC3966 (4376)

[OKUMURA Shinji <[e-mail]>]

Paul Kyzivat wrote:
>On 6/8/15 6:11 AM, OKUMURA Shinji wrote:
>> Hi Paul,
>>
>>> On 5/27/15 7:30 AM, OKUMURA Shinji wrote:
>>>> Hi,
>>>>
>>>> phonedigit is used in an extension rule.
>>>>
>>>>      extension            = ";ext=" 1*phonedigit
>>>>
>>>> if the original definition is correct, I think a following
>>>> description is valid.
>>>>
>>>> tel:1234;ext=;phone-context=example.com
>>>>
>>>> May an extension number be an empty string?
>>>
>>> That would be bad.
>>>
>>> But your errata fix isn't sufficient for extension because it would
>>> allow an extension including only visual-separators. ISTM that to
>>> complete the fix the rule for extension also needs to be changed to:
>>>
>>>    extension            = ";ext=" *phonedigit DIGIT *phonedigit
>>
>> I see, and IIUC this is reducible as below.
>>
>>     extension            = ";ext=" *visual-separator DIGIT *phonedigit
>>
>> The two are equivalent, but from a parser implementor's perspective
>> the latter is better (I think).
>
>I agree the two are equivalent. I think one can argue about which is 
>easier to understand.

I would like to add one more thing. According to the former, it is hard
to determine whether a first DIGIT is phonedigit or DIGIT.

>But for clarity I do think the same construction 
>ought to be used in both the definition of extension and 
>global-number-digits. For an errata I think it is preferable to minimize 
>the changes to the text, so I think I favor using the form currently 
>used in global-number-digits.

I agree with you.

>(If there was to be another bis, then that would be a good time to 
>change it. And then, I think I would define a new rule for this 
>construction, that would then be used in both global-number-digits and 
>extension.)

I quite agree.

Regards,
Shinji

>>>> At the very start what is the reason why visual-separator became an
>>>> optional rule?
>>>
>>> I don't know. It certainly seems to have been a mistake.
>>>
>>>> according to the document history,
>>>>
>>>> RFC2806
>>>>      phonedigit            = DIGIT / visual-separator
>>>>
>>>> draft-ietf-iptel-rfc2806bis-01
>>>>      phonedigit            =  DIGIT [ visual-separator ]
>>>>      phonedigit-hex        =  HEXDIG [ visual-separator ]
>>>>
>>>> draft-ietf-iptel-rfc2806bis-02
>>>>      phonedigit            =  DIGIT / [ visual-separator ]
>>>>      phonedigit-hex        =  HEXDIG / "*" / "#" / [ visual-separator ]
>>>
>>> 	Thanks,
>>> 	Paul
>>>
>>>> Anydody know the intent of this fix?
>>>>
>>>> Regards,
>>>> Shinji
>>>>
>>>>> This errata should be rejected.
>>>>>
>>>>> - Jason
>>>>>
>>>>>
>>>>>
>>>>> On 5/26/15, 11:47 AM, "RFC Errata System" <[e-mail]>
>>>>> wrote:
>>>>>
>>>>>> The following errata report has been submitted for RFC3966,
>>>>>> "The tel URI for Telephone Numbers".
>>>>>>
>>>>>> --------------------------------------
>>>>>> You may review the report below and at:
>>>>>> http://www.rfc-editor.org/errata_search.php?rfc=3966&eid=4376
>>>>>>
>>>>>> --------------------------------------
>>>>>> Type: Editorial
>>>>>> Reported by: OKUMURA Shinji <[e-mail]>
>>>>>>
>>>>>> Section: 3
>>>>>>
>>>>>> Original Text
>>>>>> -------------
>>>>>> phonedigit           = DIGIT / [ visual-separator ]
>>>>>> phonedigit-hex       = HEXDIG / "*" / "#" / [ visual-separator ]
>>>>>>
>>>>>>
>>>>>> Corrected Text
>>>>>> --------------
>>>>>> phonedigit           = DIGIT / visual-separator;
>>>>>> phonedigit-hex       = HEXDIG / "*" / "#" / visual-separator;
>>>>>>
>>>>>>
>>>>>> Notes
>>>>>> -----
>>>>>> An optional and alternative rule is typically meaningless.
>>>>>>
>>>>>> Instructions:
>>>>>> -------------
>>>>>> This erratum is currently posted as "Reported". If necessary, please
>>>>>> use "Reply All" to discuss whether it should be verified or
>>>>>> rejected. When a decision is reached, the verifying party (IESG)
>>>>>> can log in to change the status and edit the report, if necessary.
>>>>>>
>>>>>> --------------------------------------
>>>>>> RFC3966 (draft-ietf-iptel-rfc2806bis-09)
>>>>>> --------------------------------------
>>>>>> Title               : The tel URI for Telephone Numbers
>>>>>> Publication Date    : December 2004
>>>>>> Author(s)           : H. Schulzrinne
>>>>>> Category            : PROPOSED STANDARD
>>>>>> Source              : IP Telephony
>>>>>> Area                : Real-time Applications and Infrastructure
>>>>>> Stream              : IETF
>>>>>> Verifying Party     : IESG
>>