Doc: updated QSyntaxHighlighter documentation and use QRegularExpression

The documentation of QSyntaxHighlighter still uses the deprecated
QRegExp class. This patch updates the code samples as well as cleanup
some typos.

Change-Id: I87b525fddb560b7c5bb38f96d9aaceadb594f76c
Reviewed-by: Sze Howe Koh <szehowe.koh@gmail.com>

examples/widgets/doc/src/syntaxhighlighter.qdoc

@@ -29,8 +29,8 @@
     \example richtext/syntaxhighlighter
     \title Syntax Highlighter Example
     \ingroup examples-richtext
-    \brief The Syntax Highligher example shows how to perform
-    simple syntax highlighing.
+    \brief The Syntax Highlighter example shows how to perform
+    simple syntax highlighting.
 
     \brief The Syntax Highlighter example shows how to perform simple syntax
     highlighting by subclassing the QSyntaxHighlighter class.
@@ -64,8 +64,9 @@
     and define your own highlighting rules.
 
     We have chosen to store our highlighting rules using a private
-    struct: A rule consists of a QRegExp pattern and a QTextCharFormat
-    instance. The various rules are then stored using a QVector.
+    struct: A rule consists of a QRegularExpression pattern and a
+    QTextCharFormat instance. The various rules are then stored using a
+    QVector.
 
     The QTextCharFormat class provides formatting information for
     characters in a QTextDocument specifying the visual properties of
@@ -78,7 +79,7 @@
 
     When subclassing the QSyntaxHighlighter class you must pass the
     parent parameter to the base class constructor. The parent is the
-    text document upon which the syntax highligning will be
+    text document upon which the syntax highlighting will be
     applied. In this example, we have also chosen to define our
     highlighting rules in the constructor:
 
@@ -140,9 +141,9 @@
     HighlightingRule object) we search for the pattern in the given
     text block using the QString::indexOf() function. When the first
     occurrence of the pattern is found, we use the
-    QRegExp::matchedLength() function to determine the string that
-    will be formatted. QRegExp::matchedLength() returns the length of
-    the last matched string, or -1 if there was no match.
+    QRegularExpressionMatch::capturedLength() function to determine the string
+    that will be formatted. QRegularExpressionMatch::capturedLength() returns
+    the length of the last matched string, or 0 if there was no match.
 
     To perform the actual formatting the QSyntaxHighlighter class
     provides the \l {QSyntaxHighlighter::setFormat()}{setFormat()}

examples/widgets/richtext/syntaxhighlighter/highlighter.cpp

@@ -68,9 +68,9 @@ Highlighter::Highlighter(QTextDocument *parent)
                     << "\\bslots\\b" << "\\bstatic\\b" << "\\bstruct\\b"
                     << "\\btemplate\\b" << "\\btypedef\\b" << "\\btypename\\b"
                     << "\\bunion\\b" << "\\bunsigned\\b" << "\\bvirtual\\b"
-                    << "\\bvoid\\b" << "\\bvolatile\\b";
+                    << "\\bvoid\\b" << "\\bvolatile\\b" << "\\bbool\\b";
     foreach (const QString &pattern, keywordPatterns) {
-        rule.pattern = QRegExp(pattern);
+        rule.pattern = QRegularExpression(pattern);
         rule.format = keywordFormat;
         highlightingRules.append(rule);
 //! [0] //! [1]
@@ -80,14 +80,14 @@ Highlighter::Highlighter(QTextDocument *parent)
 //! [2]
     classFormat.setFontWeight(QFont::Bold);
     classFormat.setForeground(Qt::darkMagenta);
-    rule.pattern = QRegExp("\\bQ[A-Za-z]+\\b");
+    rule.pattern = QRegularExpression("\\bQ[A-Za-z]+\\b");
     rule.format = classFormat;
     highlightingRules.append(rule);
 //! [2]
 
 //! [3]
     singleLineCommentFormat.setForeground(Qt::red);
-    rule.pattern = QRegExp("//[^\n]*");
+    rule.pattern = QRegularExpression("//[^\n]*");
     rule.format = singleLineCommentFormat;
     highlightingRules.append(rule);
 
@@ -96,7 +96,7 @@ Highlighter::Highlighter(QTextDocument *parent)
 
 //! [4]
     quotationFormat.setForeground(Qt::darkGreen);
-    rule.pattern = QRegExp("\".*\"");
+    rule.pattern = QRegularExpression("\".*\"");
     rule.format = quotationFormat;
     highlightingRules.append(rule);
 //! [4]
@@ -104,14 +104,14 @@ Highlighter::Highlighter(QTextDocument *parent)
 //! [5]
     functionFormat.setFontItalic(true);
     functionFormat.setForeground(Qt::blue);
-    rule.pattern = QRegExp("\\b[A-Za-z0-9_]+(?=\\()");
+    rule.pattern = QRegularExpression("\\b[A-Za-z0-9_]+(?=\\()");
     rule.format = functionFormat;
     highlightingRules.append(rule);
 //! [5]
 
 //! [6]
-    commentStartExpression = QRegExp("/\\*");
-    commentEndExpression = QRegExp("\\*/");
+    commentStartExpression = QRegularExpression("/\\*");
+    commentEndExpression = QRegularExpression("\\*/");
 }
 //! [6]
 
@@ -119,12 +119,10 @@ Highlighter::Highlighter(QTextDocument *parent)
 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);
+        QRegularExpressionMatchIterator matchIterator = rule.pattern.globalMatch(text);
+        while (matchIterator.hasNext()) {
+            QRegularExpressionMatch match = matchIterator.next();
+            setFormat(match.capturedStart(), match.capturedLength(), rule.format);
         }
     }
 //! [7] //! [8]
@@ -134,22 +132,23 @@ void Highlighter::highlightBlock(const QString &text)
 //! [9]
     int startIndex = 0;
     if (previousBlockState() != 1)
-        startIndex = commentStartExpression.indexIn(text);
+        startIndex = text.indexOf(commentStartExpression);
 
 //! [9] //! [10]
     while (startIndex >= 0) {
 //! [10] //! [11]
-        int endIndex = commentEndExpression.indexIn(text, startIndex);
-        int commentLength;
+        QRegularExpressionMatch match = commentEndExpression.match(text, startIndex);
+        int endIndex = match.capturedStart();
+        int commentLength = 0;
         if (endIndex == -1) {
             setCurrentBlockState(1);
             commentLength = text.length() - startIndex;
         } else {
             commentLength = endIndex - startIndex
-                            + commentEndExpression.matchedLength();
+                            + match.capturedLength();
         }
         setFormat(startIndex, commentLength, multiLineCommentFormat);
-        startIndex = commentStartExpression.indexIn(text, startIndex + commentLength);
+        startIndex = text.indexOf(commentStartExpression, startIndex + commentLength);
     }
 }
 //! [11]

examples/widgets/richtext/syntaxhighlighter/highlighter.h

@@ -53,6 +53,7 @@
 
 #include <QSyntaxHighlighter>
 #include <QTextCharFormat>
+#include <QRegularExpression>
 
 QT_BEGIN_NAMESPACE
 class QTextDocument;
@@ -72,13 +73,13 @@ protected:
 private:
     struct HighlightingRule
     {
-        QRegExp pattern;
+        QRegularExpression pattern;
         QTextCharFormat format;
     };
     QVector<HighlightingRule> highlightingRules;
 
-    QRegExp commentStartExpression;
-    QRegExp commentEndExpression;
+    QRegularExpression commentStartExpression;
+    QRegularExpression commentEndExpression;
 
     QTextCharFormat keywordFormat;
     QTextCharFormat classFormat;