Map Development Area (MDA)
Location:
_/_
markup
_/_
xml
_/_
xpath
_/_
xpath-20
| xpath-20 |
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Other Names:
- World Wide Web Consortium. XML Path Language (XPath) Version 2.0 (long)
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Comment:
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successor to XPath 1.0 -- becomes recommendation 2004 -- subsets XQuery 1.0 -- subsets XSLT 2.0
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example
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if ($widget1/unit-cost < $widget2/unit-cost) then $widget1 else $widget2
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Comment:
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formal semantics: static: defines what an expression means without any input -- dynamic: include input
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Comment:
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many functions: string, numerics, date/time, sequence manipulation, casting
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example
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some $x in /students/student/name satisfies $x = "Fred" -- every $x in /students/student/name satisfies $x = "Fred"
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example
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sum(for $x in /order/item return $x/price * $x/quantity)
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Comment:
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data model: sequence of nodes -- arbitrary order, can have duplicates, can be heterogenous -- all expressions return sequences -- everything is a sequence -- sequences are shallow
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Comment:
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data model: typed values (as in XPath 1.0) nodes, strings, numbers, booleans -- uses XML Schema type system: simple and complex types
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