Naming Rules

[Portillo, Christina]

I need some clarification on the differences in the naming rules defined
in the XML SGML Declaration and the Naming Rules defined in XML Part 1
Names and Tokens.

My understanding of the XML SGML Declaration Naming Rules as defined in
the Concrete Syntax are:

	Naming Rules
	Identifies the rules used to identify name character and name
start characters. It also identifies case rules.

		Name Start
		XML accepts the NMSTRT default (any lower (97-122) or
upper case (65-90) alpha character) but extends this to included
character from all the other languages defined in ISO 10646. It has
specifically defined which additional characters are valid  to use as
LCNMSTRT and UCNMSTRT characters by use of ENR NAMESTRT. NAMESTRT means
that each character identified by the extended naming value has the same
effect as a character appearing in both UCNMSTRT and LCNMSTRT. The XML
SGML Declaration has defined the range of characters which have an upper
and lower case. Within this set XML has defined the underscore and colon
as being an additional NAMESTRT characters.
				 
		Name Character
		XML accepts the NMCHAR default (any lower (97-122) or
upper case (65-90) alpha character) but extends this to included
character from all the other languages defined in ISO 10646. It has
specifically defined which additional characters are valid  to use as
LCNMCHAR and UCNMCHAR characters by use of ENR NAMECHAR. NAMECHAR means
that each character identified by the extended naming value (if any) has
the same effect as a character appearing in both UCNMCHAR and LCNMCHAR.
The XML SGML Declaration has defined the range of characters which have
an upper and lower case.  Within this set XML has defined the dash and
full stop as being an additional NAMECHAR characters.
	
The XML Part 1 Names and Tokens indicates the following:

		[4] NameChar	::=	Letter | Digit | '.' | '-' | '_'
| ':' | CombiningChar | Extender
		[5] Name	::=	(Letter | '_' | ':') (NameChar)*
		[6] Names	::=	Name (S Name)*
		[7] Nmtoken	::=	(NameChar)+
		[8] Nmtokens	::=	Nmtoken (S Nmtoken)*

My understanding of the Name restricts the 1st character position to a
letter or a underscore or colon which is in sync with the SGML
Declaration. But the NameChar allows underscores and colons in the
remaining character positions which is at variance with the naming rules
defined by the SGML Declaration.

Can you clarify this for me?

Christina Portillo   
Product Definition and Image Technology

The Boeing Company               Phone: 425.237.3351
PO Box 3707   M/S 6H-AF       Fax:     425.237.3428
Seattle, WA  98124-2207         christina.portillo at boeing.com

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