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Re: Invalid attribute names

• To: xml-dev@l...
• Subject: Re: Invalid attribute names
• From: Jason Diamond <jason@i...>
• Date: Wed, 31 Dec 2003 08:42:44 -0800
• In-reply-to: <6.0.0.22.0.20031231180846.01fac7a0@p...>
• References: <20031231154553.23470.qmail@w...> <6.0.0.22.0.20031231180846.01fac7a0@p...>
• User-agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.5) Gecko/20031013 Thunderbird/0.3

But Namespaces in XML redefined what you could use as an attribute name:

[12]     Attribute      ::=     NSAttName Eq AttValue
                                        | QName Eq AttValue     [     
NSC: Prefix Declared ]

NSAttName is defines the magic xmlns attributes so let's take the QName 
alternative:

[6]     QName      ::=     (Prefix ':')? LocalPart
[7]     Prefix     ::=     NCName
[8]     LocalPart     ::=     NCName

Notice the colon is attached to the optional prefix. The LocalPart, 
being an NCName, can no longer contain colons:

[4]     NCName      ::=     (Letter | '_') (NCNameChar)*     /*     An 
XML Name, minus the ":" */
[5]     NCNameChar     ::=     Letter | Digit | '.' | '-' | '_' | 
CombiningChar | Extender

Basically, you can still have a colon in the middle of an attribute name 
(between the prefix and local part) but you can no longer have a colon 
at the beginning of an attribute name since a prefix has to appear 
before it.

Conclusion: that XML snippet *is* well-formed according to XML 1.0 but 
*not* according to Namespaces in XML. Alas.

-- Jason

Toni Uusitalo wrote:

> Spec 2.3 "Common Syntactic Constructs" says:
>
> [4]  NameChar ::=  Letter | Digit | '.' | '-' | '_' | ':' | 
> CombiningChar | Extender
> [5]  Name ::=  (Letter | '_' | ':') (NameChar)*
>
> Colon and underscore are valid name start characters.
> I believe parsers shouldn't report this as a well-formedness error.
>
>
>
> with respect,
> Toni Uusitalo

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