RE: Adam Bosworth Article - what does "directaccess"m ean?
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@f...] Sent: Sun 1/19/2003 10:38 AM To: XML DEV Cc: Subject: Re: 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@f... ----------------------------------------------------------------- The xml-dev list is sponsored by XML.org <http://www.xml.org>, an initiative of OASIS <http://www.oasis-open.org> The list archives are at http://lists.xml.org/archives/xml-dev/ To subscribe or unsubscribe from this list use the subscription manager: <http://lists.xml.org/ob/adm.pl>
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