RE: [xml-dev] Adam Bosworth Article - what does "directaccess"m ean?

["Dare Obasanjo" <dareo@microsoft.com>]

Everything W.E. Perry said about Jonathan's XQuery example applies to XPath. I assumed he also meant to state that XPath is only meant to run against virtual XML views and not UnicodeWithAngleBrackets. Which explains why no one has ever implemented XPath over XML 1.0 documents just over databases and virtual XML views... 
 
;)

	-----Original Message----- 
	From: Joe English [mailto:jenglish@flightlab.com] 
	Sent: Sun 1/19/2003 10:38 AM 
	To: XML DEV 
	Cc: 
	Subject: Re: [xml-dev] Adam Bosworth Article - what does "directaccess"m ean?
	
	


	W. E. Perry wrote:
	>
	> I'm sorry, Jonathan, I don't understand. What is
	>
	>     return $stock/price / ($stock/revenues - $stock/expenses)
	>
	> except the execution of subtraction and division arithmetic
	> operations agains t the 'values' of $stock/price,
	> $stock/revenues, and $stock/expenses? And if your query
	> is against XML, then the values of those i tems are
	> runs of Unicode text, and your arithmetic operations
	> are effectively meaningless.
	
	
	Not necessarily: the infix operator "-" can easily be
	defined as an operation on strings.   Parse the left and
	right operands as numbers (raising an error if they're not
	syntactically valid), subtract one from the other, then
	format the result as a string.
	
	That's precisely how Tcl works.  That's why I find Tcl
	eminently suitable for processing SGML: "everything is a
	string" is a mantra that works in both worlds.  (And no,
	contrary to popular belief, this doesn't make Tcl horribly
	inefficient.)
	
	I don't know if XQuery works that way -- haven't kept up
	with the spec.  XPath does, sort of, except that it has
	IEEE floating point as a built-in data type in addition
	to strings and that complicates things a bit.
	
	
	--Joe English
	
	  jenglish@flightlab.com
	
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