--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/xmlpatterns/functions/qsequencefns_p.h Mon Jan 11 14:00:40 2010 +0000
@@ -0,0 +1,344 @@
+/****************************************************************************
+**
+** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
+** All rights reserved.
+** Contact: Nokia Corporation (qt-info@nokia.com)
+**
+** This file is part of the QtXmlPatterns module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** No Commercial Usage
+** This file contains pre-release code and may not be distributed.
+** You may use this file in accordance with the terms and conditions
+** contained in the Technology Preview License Agreement accompanying
+** this package.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Nokia gives you certain additional
+** rights. These rights are described in the Nokia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** If you have questions regarding the use of this file, please contact
+** Nokia at qt-info@nokia.com.
+**
+**
+**
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+//
+// W A R N I N G
+// -------------
+//
+// This file is not part of the Qt API. It exists purely as an
+// implementation detail. This header file may change from version to
+// version without notice, or even be removed.
+//
+// We mean it.
+
+#ifndef Patternist_SequenceFNs_H
+#define Patternist_SequenceFNs_H
+
+#include "qatomiccomparator_p.h"
+#include "qcomparisonplatform_p.h"
+#include "qliteral_p.h"
+#include "qfunctioncall_p.h"
+
+/**
+ * @file
+ * @short Contains classes implementing the functions found in
+ * <a href="http://www.w3.org/TR/xpath-functions/#general-seq-funcs">XQuery 1.0 and
+ * XPath 2.0 Functions and Operators, 15.1 General Functions and Operators on Sequences</a>.
+ *
+ * @todo document that some functions have both eval funcs implented.
+ *
+ * @ingroup Patternist_functions
+ */
+
+QT_BEGIN_HEADER
+
+QT_BEGIN_NAMESPACE
+
+namespace QPatternist
+{
+ /**
+ * @short Implements the function <tt>fn:boolean()</tt>.
+ *
+ * @see EBVExtractor
+ * @ingroup Patternist_functions
+ * @author Frans Englich <frans.englich@nokia.com>
+ */
+ class BooleanFN : public FunctionCall
+ {
+ public:
+ virtual bool evaluateEBV(const DynamicContext::Ptr &context) const;
+
+ /**
+ * If @p reqType is CommonSequenceTypes::EBV, the type check of
+ * the operand is returned. Hence, this removes redundant calls
+ * to <tt>fn:boolean()</tt>.
+ */
+ virtual Expression::Ptr typeCheck(const StaticContext::Ptr &context,
+ const SequenceType::Ptr &reqType);
+ };
+
+ /**
+ * @short Implements the function <tt>fn:index-of()</tt>.
+ *
+ * @ingroup Patternist_functions
+ * @author Frans Englich <frans.englich@nokia.com>
+ */
+ class IndexOfFN : public FunctionCall,
+ public ComparisonPlatform<IndexOfFN, false>
+ {
+ public:
+ inline IndexOfFN() : ComparisonPlatform<IndexOfFN, false>()
+ {
+ }
+
+ virtual Item::Iterator::Ptr evaluateSequence(const DynamicContext::Ptr &context) const;
+ virtual Expression::Ptr typeCheck(const StaticContext::Ptr &context,
+ const SequenceType::Ptr &reqType);
+
+ inline AtomicComparator::Operator operatorID() const
+ {
+ return AtomicComparator::OperatorEqual;
+ }
+ };
+
+ /**
+ * @short Implements the functions <tt>fn:exists()</tt> and <tt>fn:empty()</tt>.
+ *
+ * Existence is a template value class. Appropriate implementations are achieved
+ * by instantiating it with either IDExistsFN or IDEmptyFN.
+ *
+ * @ingroup Patternist_functions
+ * @author Frans Englich <frans.englich@nokia.com>
+ */
+ template<const Expression::ID Id>
+ class Existence : public FunctionCall
+ {
+ public:
+ virtual bool evaluateEBV(const DynamicContext::Ptr &context) const
+ {
+ if(Id == IDExistsFN)
+ return !m_operands.first()->evaluateSequence(context)->isEmpty();
+ else
+ return m_operands.first()->evaluateSequence(context)->isEmpty();
+ }
+
+ /**
+ * Attempts to rewrite to @c false or @c true by looking at the static
+ * cardinality of its operand.
+ */
+ virtual Expression::Ptr compress(const StaticContext::Ptr &context)
+ {
+ // RVCT doesn't like using template parameter in trinary operator when the trinary operator result is
+ // passed directly into another constructor.
+ Q_ASSERT(Id == IDExistsFN || Id == IDEmptyFN);
+
+ const Expression::Ptr me(FunctionCall::compress(context));
+
+ if(me != this)
+ return me;
+
+ // RVCT doesn't like using template parameter in trinary operator when the trinary operator result is
+ // passed directly into another constructor.
+ Expression::ID tempId = Id;
+ const Cardinality myCard((tempId == IDExistsFN) ? Cardinality::oneOrMore() : Cardinality::empty());
+
+ const Cardinality card(m_operands.first()->staticType()->cardinality());
+ if(myCard.isMatch(card))
+ { /* Since the dynamic type always is narrower than the static type or equal, and that the
+ static type is in scope, it means we will always be true. */
+ return wrapLiteral(CommonValues::BooleanTrue, context, this);
+ }
+ else
+ {
+ /* Is it even possible to hit? */
+ if(myCard.canMatch(card))
+ {
+ return me;
+ }
+ else
+ { /* We can never hit. */
+ return wrapLiteral(CommonValues::BooleanFalse, context, this);
+ }
+ }
+ }
+ };
+
+ /**
+ * @short Implements the function <tt>fn:distinct-values()</tt>.
+ *
+ * @ingroup Patternist_functions
+ * @author Frans Englich <frans.englich@nokia.com>
+ */
+ class DistinctValuesFN : public FunctionCall,
+ public ComparisonPlatform<IndexOfFN, false>
+ {
+ public:
+ inline DistinctValuesFN() : ComparisonPlatform<IndexOfFN, false>()
+ {
+ }
+
+ virtual Item::Iterator::Ptr evaluateSequence(const DynamicContext::Ptr &context) const;
+ /**
+ * Performs necessary type checks, but also implements the optimization
+ * of rewriting to its operand if the operand's cardinality is zero-or-one
+ * or exactly-one.
+ */
+ virtual Expression::Ptr typeCheck(const StaticContext::Ptr &context,
+ const SequenceType::Ptr &reqType);
+ /**
+ * @returns a type whose item type is the type of the first operand, and
+ * a cardinality which is non-empty if the first operand's type is non-empty
+ * and allows exactly-one. The latter is needed for operands which has the
+ * cardinality 2+, since distinct-values possibly removes items from the
+ * source sequence.
+ */
+ virtual SequenceType::Ptr staticType() const;
+
+ protected:
+ inline AtomicComparator::Operator operatorID() const
+ {
+ return AtomicComparator::OperatorEqual;
+ }
+ };
+
+ /**
+ * @short Implements the function <tt>fn:insert-before()</tt>.
+ *
+ * @todo docs, explain why evaluateSequence and evaluateSingleton is implemented
+ *
+ * @ingroup Patternist_functions
+ * @author Frans Englich <frans.englich@nokia.com>
+ */
+ class InsertBeforeFN : public FunctionCall
+ {
+ public:
+ virtual Item::Iterator::Ptr evaluateSequence(const DynamicContext::Ptr &context) const;
+ virtual Item evaluateSingleton(const DynamicContext::Ptr &context) const;
+
+ /**
+ * Implements the static enferences rules. The function's static item type
+ * is the union type of the first and third argument, and the cardinality is
+ * the cardinalities of the two operands added together. For example,
+ * insert-before((1, "str"), 1, xs:double(0)) has the static type xs:anyAtomicType+.
+ *
+ * @see <a href="http://www.w3.org/TR/xquery-semantics/#sec_fn_insert_before">XQuery 1.0
+ * and XPath 2.0 Formal Semantics, 7.2.15 The fn:insert-before function</a>
+ */
+ virtual SequenceType::Ptr staticType() const;
+ };
+
+ /**
+ * @short Implements the function <tt>fn:remove()</tt>.
+ *
+ * @ingroup Patternist_functions
+ * @author Frans Englich <frans.englich@nokia.com>
+ */
+ class RemoveFN : public FunctionCall
+ {
+ public:
+ virtual Item::Iterator::Ptr evaluateSequence(const DynamicContext::Ptr &context) const;
+ virtual Item evaluateSingleton(const DynamicContext::Ptr &context) const;
+
+ /**
+ * Implements the static enferences rules, "Since one item may be removed
+ * from the sequence, the resulting type is made optional:"
+ *
+ * <tt>statEnv |- (FN-URI,"remove")(Type, Type1) : prime(Type) * quantifier(Type)?</tt>
+ *
+ * However, because Patternist's type system is more fine grained than Formal Semantics,
+ * the sequence isn't made optional. Instead its minimum length is reduced with one.
+ *
+ * @see <a href="http://www.w3.org/TR/xquery-semantics/#sec_fn_remove">XQuery 1.0
+ * and XPath 2.0 Formal Semantics, 7.2.11 The fn:remove function</a>
+ */
+ virtual SequenceType::Ptr staticType() const;
+ };
+
+ /**
+ * @short Implements the function <tt>fn:reverse()</tt>.
+ *
+ * @ingroup Patternist_functions
+ * @author Frans Englich <frans.englich@nokia.com>
+ */
+ class ReverseFN : public FunctionCall
+ {
+ public:
+
+ virtual Item::Iterator::Ptr evaluateSequence(const DynamicContext::Ptr &context) const;
+ virtual Expression::Ptr typeCheck(const StaticContext::Ptr &context,
+ const SequenceType::Ptr &reqType);
+
+ /**
+ * Formally speaking, the type inference is:
+ *
+@verbatim
+statEnv |- (FN-URI,"reverse")(Type) : prime(Type) * quantifier(Type)
+@endverbatim
+ *
+ * @see <a href="http://www.w3.org/TR/xquery-semantics/#sec_fn_reverse">XQuery 1.0
+ * and XPath 2.0 Formal Semantics, 7.2.12 The fn:reverse function</a>
+ * @returns the static type of the function's first argument.
+ */
+ virtual SequenceType::Ptr staticType() const;
+ };
+
+ /**
+ * @short Implements the function <tt>fn:subsequence()</tt>.
+ *
+ * @ingroup Patternist_functions
+ * @author Frans Englich <frans.englich@nokia.com>
+ * @todo Type inference can be made stronger for this function
+ */
+ class SubsequenceFN : public FunctionCall
+ {
+ public:
+ SubsequenceFN();
+ virtual Item::Iterator::Ptr evaluateSequence(const DynamicContext::Ptr &context) const;
+ virtual Item evaluateSingleton(const DynamicContext::Ptr &context) const;
+
+ virtual Expression::Ptr typeCheck(const StaticContext::Ptr &context,
+ const SequenceType::Ptr &reqType);
+
+ /**
+ * This function implements rewrites the SubsequenceFN instance into an
+ * empty sequence if its third argument, the sequence length argument, is
+ * evaluated and is effectively equal or less than zero.
+ */
+ virtual Expression::Ptr compress(const StaticContext::Ptr &context);
+
+ /**
+ * Partially implements the static type inference rules.
+ *
+ * @see <a href="http://www.w3.org/TR/xquery-semantics/#sec_fn_subsequence">XQuery 1.0
+ * and XPath 2.0 Formal Semantics, 7.2.13 The fn:subsequence function</a>
+ */
+ virtual SequenceType::Ptr staticType() const;
+
+ private:
+ bool m_hasTypeChecked;
+ };
+}
+
+QT_END_NAMESPACE
+
+QT_END_HEADER
+
+#endif