QSyntaxHighlighter multiline comment in document not appearing correctly - regex

Question

Referring to Syntax Highlighter Example provided by QT official website, I tried to implement (actually you can call copy paste) the same logic for multiline comment in my application. For reference this is the code for multiline comment highlighting:
Inside the constructor:
quotationFormat.setForeground(QColor(164, 14, 14));
rule.pattern = QRegExp("\".*\"");
rule.format = quotationFormat;
highlightingRules.append(rule);
charFormat.setForeground(QColor(164, 14, 14));
rule.pattern = QRegExp("\'.*\'");
rule.format = charFormat;
highlightingRules.append(rule);
singleLineCommentFormat.setForeground(Qt::darkGreen);
rule.pattern = QRegExp("//[^\n]*");
rule.format = singleLineCommentFormat;
highlightingRules.append(rule);
multiLineCommentFormat.setForeground(Qt::darkGreen);
commentStartExpression = QRegExp("/\\*");
commentEndExpression = QRegExp("\\*/");
Inside the highlightBlock() function:
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);
}
But still there is problem I am facing when /* appears inside quotes. It appears with the multiline comment color (green color) till the end ( /*.png" ] } ) See the following sample document content for reference:
{
"code": [
"./Code/Main.js"
],
"textures": [
"./Content/*.png"
]
}
I am not master of Regular Expression, but I guess there is something wrong with the Regex.

Answer 1

With some luck and effort I have found a workaround (still it'll not cover all the cases)
int MySyntaxHighlighter::getCommentStartIndex(const QString &text, const int offset)
{
int startIndex = -1;
qDebug() << "offset: " << offset;
if(text.length() > 1 && offset < (text.length() - 1)) {
int commentStartIndex = commentStartExpression.indexIn(text, offset);
qDebug() << "commentStartIndex: " << commentStartIndex;
QRegExp quotationExpression(quotationRule.pattern);
int quotationStartIndex = quotationExpression.indexIn(text, offset);
qDebug() << "quotationStartIndex: " << quotationStartIndex;
if (quotationStartIndex >= 0) {
int quotationLength = quotationExpression.matchedLength();
qDebug() << "quotationLength: " << quotationLength;
if(commentStartIndex > quotationStartIndex &&
commentStartIndex < (quotationStartIndex + quotationLength)) {
startIndex = getCommentStartIndex(text, (commentStartIndex + 2));
} else {
startIndex = commentStartIndex;
}
} else if(commentStartIndex >= 0) {
startIndex = commentStartIndex;
} else {
startIndex = -1;
}
}
qDebug() << "startIndex: " << startIndex;
return startIndex;
}
void MySyntaxHighlighter::highlightBlock(const QString &text)
{
setCurrentBlockState(0);
qDebug() << "text: " << text;
qDebug() << "previousBlockState(): " << previousBlockState();
int startIndex = 0;
if (previousBlockState() != 1) {
// startIndex = commentEndExpression.indexIn(text);
startIndex = getCommentStartIndex(text, 0);
}
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);
startIndex = getCommentStartIndex(text, startIndex + commentLength);
}
}
If someone finds a better solution please share it with me.