highlighter.cpp Example File

 /****************************************************************************
 **
 ** Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
 ** All rights reserved.
 ** Contact: Nokia Corporation ([email protected])
 **
 ** This file is part of the examples of the Qt Toolkit.
 **
 ** $QT_BEGIN_LICENSE:BSD$
 ** You may use this file under the terms of the BSD license as follows:
 **
 ** "Redistribution and use in source and binary forms, with or without
 ** modification, are permitted provided that the following conditions are
 ** met:
 **   * Redistributions of source code must retain the above copyright
 **     notice, this list of conditions and the following disclaimer.
 **   * Redistributions in binary form must reproduce the above copyright
 **     notice, this list of conditions and the following disclaimer in
 **     the documentation and/or other materials provided with the
 **     distribution.
 **   * Neither the name of Nokia Corporation and its Subsidiary(-ies) nor
 **     the names of its contributors may be used to endorse or promote
 **     products derived from this software without specific prior written
 **     permission.
 **
 ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 ** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 ** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 ** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 ** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 ** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 ** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 ** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 ** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 ** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 ** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
 ** $QT_END_LICENSE$
 **
 ****************************************************************************/

 #include <QtGui>

 #include "highlighter.h"

 Highlighter::Highlighter(QTextDocument *parent)
     : QSyntaxHighlighter(parent)
 {
     HighlightingRule rule;

     keywordFormat.setForeground(Qt::darkBlue);
     keywordFormat.setFontWeight(QFont::Bold);
     QStringList keywordPatterns;
     keywordPatterns << "\\bchar\\b" << "\\bclass\\b" << "\\bconst\\b"
                     << "\\bdouble\\b" << "\\benum\\b" << "\\bexplicit\\b"
                     << "\\bfriend\\b" << "\\binline\\b" << "\\bint\\b"
                     << "\\blong\\b" << "\\bnamespace\\b" << "\\boperator\\b"
                     << "\\bprivate\\b" << "\\bprotected\\b" << "\\bpublic\\b"
                     << "\\bshort\\b" << "\\bsignals\\b" << "\\bsigned\\b"
                     << "\\bslots\\b" << "\\bstatic\\b" << "\\bstruct\\b"
                     << "\\btemplate\\b" << "\\btypedef\\b" << "\\btypename\\b"
                     << "\\bunion\\b" << "\\bunsigned\\b" << "\\bvirtual\\b"
                     << "\\bvoid\\b" << "\\bvolatile\\b";
     foreach (const QString &pattern, keywordPatterns) {
         rule.pattern = QRegExp(pattern);
         rule.format = keywordFormat;
         highlightingRules.append(rule);
     }

     classFormat.setFontWeight(QFont::Bold);
     classFormat.setForeground(Qt::darkMagenta);
     rule.pattern = QRegExp("\\bQ[A-Za-z]+\\b");
     rule.format = classFormat;
     highlightingRules.append(rule);

     singleLineCommentFormat.setForeground(Qt::red);
     rule.pattern = QRegExp("//[^\n]*");
     rule.format = singleLineCommentFormat;
     highlightingRules.append(rule);

     multiLineCommentFormat.setForeground(Qt::red);

     quotationFormat.setForeground(Qt::darkGreen);
     rule.pattern = QRegExp("\".*\"");
     rule.format = quotationFormat;
     highlightingRules.append(rule);

     functionFormat.setFontItalic(true);
     functionFormat.setForeground(Qt::blue);
     rule.pattern = QRegExp("\\b[A-Za-z0-9_]+(?=\\()");
     rule.format = functionFormat;
     highlightingRules.append(rule);

     commentStartExpression = QRegExp("/\\*");
     commentEndExpression = QRegExp("\\*/");
 }

 void Highlighter::highlightBlock(const QString &text)
 {
     foreach (const HighlightingRule &rule, highlightingRules) {
         QRegExp expression(rule.pattern);
         int index = expression.indexIn(text);
         while (index >= 0) {
             int length = expression.matchedLength();
             setFormat(index, length, rule.format);
             index = expression.indexIn(text, index + length);
         }
     }
     setCurrentBlockState(0);

     int startIndex = 0;
     if (previousBlockState() != 1)
         startIndex = commentStartExpression.indexIn(text);

     while (startIndex >= 0) {
         int endIndex = commentEndExpression.indexIn(text, startIndex);
         int commentLength;
         if (endIndex == -1) {
             setCurrentBlockState(1);
             commentLength = text.length() - startIndex;
         } else {
             commentLength = endIndex - startIndex
                             + commentEndExpression.matchedLength();
         }
         setFormat(startIndex, commentLength, multiLineCommentFormat);
         startIndex = commentStartExpression.indexIn(text, startIndex + commentLength);
     }
 }