Match Patterns (Locating Elements)
One critical capability of a stylesheet language is to locate source
elements to be styled. CSS, for example, does this with "selectors."
FOSIs do it with "e-i-c's", elements in context. XSLT does it
with "match patterns" defined by the XML Path Language (XPath) (http://www.w3.org/TR/xpath).
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XPath has an extensible string-based syntax
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It describes "location paths" between parts of
a document or documents
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One inspiration for XPath was the common "path/file"
file system syntax
Two things to remember about XPath expressions:
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Pattern matching occurs in a context; XPath expressions and
XSLT elements can change the current context and consequently the nodes which
match
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XPath is inclusive or greedy, it addresses all
matching elements. You must use predicates to refine the set of
nodes selected.
