/**************************************************************************** ** ** Copyright (C) 2010 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. ** ** $QT_BEGIN_LICENSE:LGPL$ ** Commercial Usage ** Licensees holding valid Qt Commercial licenses may use this file in ** accordance with the Qt Commercial License Agreement provided with the ** Software or, alternatively, in accordance with the terms contained in ** a written agreement between you and Nokia. ** ** 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. 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This header file may change from version to // version without notice, or even be removed. // // We mean it. /** * @file * @short Contains Doxygen documentation for groups. */ namespace QPatternist { /** * @short The abstract syntax tree nodes that implements the builtin * functions, such as @c fn:concat(). * * @defgroup Patternist_functions Function Implementations * @author Frans Englich */ /** * @short The abstract syntax tree nodes that is generated for XPath, * XQuery, and XSL-T code. * * XPath's approach of compilation is traditional. An Abstract Syntax * Tree(AST) is built, where the Expression class is the abstract base * class for all kinds of implementations of expressions. * * What perhaps can be said to be characteristic for Patternist is that the * base class, Expression, performs a lot of work, and that sub-classes * declares what specific behaviors they need, which the Expression's * functions then bring into action. * * XPath expressions often have different amount of operands. For example, * the 'and' expression takes two, the context item(".") none, and the * if-expression three. To help expression implementations with that, there * exist the abstract EmptyContainer, SingleContainer, PairContainer, * TripleContainer, and UnlimitedContainer classes for avoiding duplicating * code. * * @defgroup Patternist_expressions Expressions * @author Frans Englich */ /** * @short Various classes that contains small utility functions. * * @defgroup Patternist Utility Classes * @author Frans Englich */ /** * @short Classes for the type system in the XQuery & XSL-T language. * * @defgroup Patternist_types Type system * @author Frans Englich */ /** * @defgroup Patternist_xdm XQuery/XPath Data Model * @author Frans Englich */ /** * @short Patternist's family of iterators in one of the most central parts * of Patternist's API, and are responsible for carrying, and typically * also creating, data. * * An iterator, which always is an Iterator sub-class, is similar to a * Java-style iterator. What signifies Patternist's iterators is that they * almost always contains business logic(which is the cause to their * efficiency). * * An example which illustrates this principle is the RangeIterator. When * the RangeExpression is told to create a sequence of integers between 1 * and 1000, it doesn't enter a loop that allocates 1000 Integer instances, * but instead return an RangeIterator that incrementally creates the * numbers when asked to do so via its RangeIterator::next() function. If * it turns out that the expression that has the range expression as * operand only needs three items from it, that is what gets created, not * 1000. * * All iterators operates by that principle, perhaps suitably labeled as * "pull-based", "lazy loaded" or "serialized". Central for the XPath * language is that it filters and selects data, and the iterators supports * this well by letting the demand of the filter expressions(the callees) * decide how "much" source that gets computed. In this way the evaluation * of an expression tree can lead to a chain of pipelined iterators, where * the first asks the second for data and then performs its specific * operations, the second subsequently asks the third, and so forth. * * However, the iterators are not limited to be used for representing * sequences of items in the XPath Data Model. The Iterator is * parameterized on one argument, meaning any type of "units" can be * iterated, be it Item or any other. One use of this is in the * ExpressionSequence(which implements the comma operator) where it creates * Iterator instances over Expression instances -- its operands. The * parameterization is often used in combination with the MappingIterator * and the MappingCallback. * * @defgroup Patternist_iterators Iterators * @author Frans Englich */ }