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https://github.com/jezhiggins/arabica
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235f81718d
To ease implementing scan, BinaryExpression and UnaryExpression now inherit XPathExpression_impl. Other classes now derived only from Binary|UnaryExpression rather than from XPathExpression_impl as well.
60 lines
2 KiB
C++
60 lines
2 KiB
C++
#ifndef ARABICA_XPATHIC_XPATH_UNION_HPP
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#define ARABICA_XPATHIC_XPATH_UNION_HPP
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#include "xpath_value.hpp"
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#include <algorithm>
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namespace Arabica
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{
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namespace XPath
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{
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namespace impl
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{
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template<class string_type, class string_adaptor>
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class UnionExpression : public BinaryExpression<string_type, string_adaptor>
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{
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typedef BinaryExpression<string_type, string_adaptor> baseT;
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public:
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UnionExpression(XPathExpression_impl<string_type, string_adaptor>* lhs,
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XPathExpression_impl<string_type, string_adaptor>* rhs) :
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BinaryExpression<string_type, string_adaptor>(lhs, rhs) { }
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virtual ValueType type() const { return NODE_SET; }
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virtual XPathValue<string_type, string_adaptor> evaluate(const DOM::Node<string_type, string_adaptor>& context,
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const ExecutionContext<string_type, string_adaptor>& executionContext) const
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{
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XPathValue<string_type, string_adaptor> p1 = baseT::lhs()->evaluate(context, executionContext);
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if(p1.type() != NODE_SET)
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throw RuntimeException("Union operator joins node-sets. First argument is not a node-set.");
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XPathValue<string_type, string_adaptor> p2 = baseT::rhs()->evaluate(context, executionContext);
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if(p2.type() != NODE_SET)
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throw RuntimeException("Union operator joins node-sets. Second argument is not a node-set.");
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NodeSet<string_type, string_adaptor> ns1(p1.asNodeSet());
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NodeSet<string_type, string_adaptor> ns2(p2.asNodeSet());
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// do the obvious optimizations
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if(ns1.empty())
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return wrap(ns2);
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if(ns2.empty())
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return wrap(ns1);
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ns1.insert(ns1.end()-1, ns2.begin(), ns2.end());
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ns1.to_document_order();
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return wrap(ns1);
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} // evaluate
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private:
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XPathValue<string_type, string_adaptor> wrap(const NodeSet<string_type, string_adaptor>& ns) const
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{
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return XPathValue<string_type, string_adaptor>(new NodeSetValue<string_type, string_adaptor>(ns));
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} // wrap
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}; // UnionExpression
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} // namespace impl
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} // namespace XPath
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} // namespace Arabica
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#endif
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