Update QSyntaxHighlighter docs to use QRegularExpression

Update the QSyntaxHighlighter examples to use the new QRegularExpression
class in place of QRegExp.

Fix typos. Remove duplicated snippet. Replace lengthy section of
duplicate text in highlight(..) with a note to see the detailed
description.

Task-number: QTBUG-58494
Change-Id: Id8d94bddbed52e6e52feac107f6fc84e2fe4518a
Reviewed-by: Samuel Gaist <samuel.gaist@edeltech.ch>
Reviewed-by: Sze Howe Koh <szehowe.koh@gmail.com>

1 files changed, 12 insertions, 31 deletions

diff --git a/src/gui/doc/snippets/code/src_gui_text_qsyntaxhighlighter.cpp b/src/gui/doc/snippets/code/src_gui_text_qsyntaxhighlighter.cpp
index da960088b7..bb27eb9612 100644
--- a/src/gui/doc/snippets/code/src_gui_text_qsyntaxhighlighter.cpp
+++ b/src/gui/doc/snippets/code/src_gui_text_qsyntaxhighlighter.cpp
@@ -60,14 +60,13 @@ void MyHighlighter::highlightBlock(const QString &text)
     QTextCharFormat myClassFormat;
     myClassFormat.setFontWeight(QFont::Bold);
     myClassFormat.setForeground(Qt::darkMagenta);
-    QString pattern = "\\bMy[A-Za-z]+\\b";
 
-    QRegExp expression(pattern);
-    int index = text.indexOf(expression);
-    while (index >= 0) {
-        int length = expression.matchedLength();
-        setFormat(index, length, myClassFormat);
-        index = text.indexOf(expression, index + length);
+    QRegularExpression expression("\\bMy[A-Za-z]+\\b");
+    QRegularExpressionMatchIterator i = expression.globalMatch(text);
+    while (i.hasNext())
+    {
+      QRegularExpressionMatch match = i.next();
+      setFormat(match.capturedStart(), match.capturedLength(), myClassFormat);
     }
 }
 //! [1]
@@ -77,8 +76,8 @@ void MyHighlighter::highlightBlock(const QString &text)
 QTextCharFormat multiLineCommentFormat;
 multiLineCommentFormat.setForeground(Qt::red);
 
-QRegExp startExpression("/\\*");
-QRegExp endExpression("\\*/");
+QRegularExpression startExpression("/\\*");
+QRegularExpression endExpression("\\*/");
 
 setCurrentBlockState(0);
 
@@ -87,14 +86,15 @@ if (previousBlockState() != 1)
     startIndex = text.indexOf(startExpression);
 
 while (startIndex >= 0) {
-   int endIndex = text.indexOf(endExpression, startIndex);
+   QRegularExpressionMatch endMatch;
+   int endIndex = text.indexOf(endExpression, startIndex, &endMatch);
    int commentLength;
    if (endIndex == -1) {
        setCurrentBlockState(1);
        commentLength = text.length() - startIndex;
    } else {
        commentLength = endIndex - startIndex
-                       + endExpression.matchedLength();
+                       + endMatch.capturedLength();
    }
    setFormat(startIndex, commentLength, multiLineCommentFormat);
    startIndex = text.indexOf(startExpression,
@@ -104,25 +104,6 @@ while (startIndex >= 0) {
 
 
 //! [3]
-void MyHighlighter::highlightBlock(const QString &text)
-{
-    QTextCharFormat myClassFormat;
-    myClassFormat.setFontWeight(QFont::Bold);
-    myClassFormat.setForeground(Qt::darkMagenta);
-    QString pattern = "\\bMy[A-Za-z]+\\b";
-
-    QRegExp expression(pattern);
-    int index = text.indexOf(expression);
-    while (index >= 0) {
-        int length = expression.matchedLength();
-        setFormat(index, length, myClassFormat);
-        index = text.indexOf(expression, index + length);
-     }
- }
-//! [3]
-
-
-//! [4]
 struct ParenthesisInfo
 {
     QChar char;
@@ -133,4 +114,4 @@ struct BlockData : public QTextBlockUserData
 {
     QVector<ParenthesisInfo> parentheses;
 };
-//! [4]
+//! [3]