What's implementable in XPath expressions?

• From: Howard Katz <howardk@fatdog.com>
• Date: Wed, 25 Apr 2001 16:49:08 -0700
• To: <www-ql@w3.org>
• Message-ID: <NDBBIAJFNKNOBCIODNKDOEEBCEAA.howardk@fatdog.com>

What's actually implementable at the head of an XPath expression? I'm trying
to figure out what's allowed by the following snippet from the JavaCup
grammar:

PathExpression :=
	Path
	| ( SLASH | DOUBLE_SLASH ) Path
	| BasicExpression OptionalPredicates (SLASH | DOUBLE_SLASH) Path

BasicExpression :=
	VAR
	| Literal
	| FunctionName L_PAREN OptionalExpressionList R_PAREN
	| L_PAREN Expression R_PAREN
	| ElementConstructor
	| ListConstructor
	| CastVerb AS ...
	| DOT

Certainly $VarName/somePath and DOT/somePath are going to be commonly seen,
but what about the others? What's the meaning of
[ElementConstructor]/somePath, for example? Or even [Literal]/somePath? How
should I interpret these constructs?

Howard

Received on Wednesday, 25 April 2001 19:49:16 UTC