| <html><head><META http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>SequenceType Matching Expressions</title><link href="book.css" type="text/css" rel="stylesheet"><link href="book.css" type="text/css" rel="stylesheet"><meta content="DocBook XSL Stylesheets V1.76.1" name="generator"><link rel="home" href="index.html" title="usermanual"><link rel="up" href="ch02s03.html" title="How to use the XPath 2.0 grammar with PsychoPath"><link rel="prev" href="ch02s03s10.html" title="And, Or Expressions"><link rel="next" href="ch03.html" title="How to use XPath 2.0 functions with PsychoPath"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="section" title="SequenceType Matching Expressions"><div class="titlepage"><div><div><h3 class="title"><a name="SequenceType_Matching_Expressions"></a>SequenceType Matching Expressions</h3></div></div></div><p>The rules for SequenceType matching compare the actual type of a value with an expected type. These rules are a subset of the formal rules that match a value with an expected type defined in XQuery 1.0 and XPath 2.0 Formal Semantics |
| <a class="ulink" href="http://www.w3.org/TR/xpath20/#XQueryFormalSemantics" target="_top">http://www.w3.org/TR/xpath20/#XQueryFormalSemantics</a>, because the Formal Semantics must be able to match a value with any XML Schema type, whereas the rules below only match values against those types expressible by the SequenceType syntax. |
| </p><p>Some of the rules for SequenceType matching require determining whether a given type name is the same as or derived from an expected type name. The given type name may be "known" (defined in the in-scope schema definitions), or "unknown" (not defined in the in-scope schema definitions). An unknown type name might be encountered, for example, if a source document has been validated using a schema that was not imported into the static context. In this case, an implementation is allowed (but is not required) to provide an implementation-dependent mechanism for determining whether the unknown type name is derived from the expected type name. For example, an implementation might maintain a data dictionary containing information about type hierarchies. consider the following XML document: |
| <source lang="xml"><sorbo></p><div class="literallayout"><p> <is>elite</is><br> |
| <!-- life sux --><br> |
| </p></div><p></sorbo> |
| |
| then, the following are some example of SequenceType matchings: </p><div class="literallayout"><p>element({*})<br> |
| </p></div><p> |
| |
| <span class="bold"><strong>result:</strong></span> |
| </p><div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem"><p>element: sorbo</p></li></ol></div><p> |
| </p><div class="literallayout"><p>element(elite)<br> |
| </p></div><p> |
| |
| <span class="bold"><strong>result:</strong></span> |
| </p><div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem"><p>Empty results</p></li></ol></div><div class="literallayout"><p> sorbo/comment()<br> |
| </p></div><p> |
| |
| <span class="bold"><strong>result:</strong></span> |
| </p><div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem"><p>comment: life sux</p></li></ol></div><div class="literallayout"><p> data(/sorbo/comment())<br> |
| </p></div><p> |
| |
| <span class="bold"><strong>result:</strong></span> |
| </p><div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem"><p>xs:string: life sux</p></li></ol></div><p> |
| </p><div class="literallayout"><p>sorbo/node()<br> |
| </p></div><p> |
| |
| <span class="italic">'result: '</span> |
| </p><div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem"><p>text: </p></li><li class="listitem"><p>element: is </p></li><li class="listitem"><p>comment: life sux </p></li><li class="listitem"><p>text:</p></li></ol></div><p> |
| </p></div></body></html> |
