highlighter.cpp Example File

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  #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);
      }
  }