Match nested capture groups with quantifiers using QRegularExpression - c++

Question

I'm trying to get with a QRegularExpression all attributes of an xml tag in the different captured groups. I use a regex matching the tags and I manage to get the capture groups containing the attribute value but with a quantifier, I get only the last one.
I use this regex :
<[a-z]+(?: [a-z]+=("[^"]*"))*>
And I would like to get "a" and "b" with this text :
<p a="a" b="b">
Here is the code:
const QString text { "<p a=\"a\" b=\"b\">" };
const QRegularExpression pattern { "<[a-z]+(?: [a-z]+=(\"[^\"]*\"))*>" };
QRegularExpressionMatchIterator it = pattern.globalMatch(text);
while (it.hasNext())
{
const QRegularExpressionMatch match = it.next();
qDebug() << "Match with" << match.lastCapturedIndex() + 1 << "captured groups";
for (int i { 0 }; i <= match.lastCapturedIndex(); ++i)
qDebug() << match.captured(i);
}
And the output :
Match with 2 captured groups
"<p a=\"a\" b=\"b\">"
"\"b\""
Is it possible to get multiple capture groups with the quantifier * or have I to iterate using QRegularExpressionMatchIterator with a specific regex on the string literals?

Answer 1

This expression might help you to simply capture those attributes and it is not bounded from left and right:
([A-z]+)(=\x22)([A-z]+)(\x22)
Graph
This graph shows how the expression would work and you can visualize other expressions in this link, if you wish to know:
If you would like to add additional boundaries to it, which you might want to do so, you can further extend it, maybe to something similar to:
(?:^<p )?([A-z]+)(=\x22)([A-z]+)(\x22)
Test for RegEx
const regex = /(?:^<p )?([A-z]+)(=\x22)([A-z]+)(\x22)/gm;
const str = `<p attributeA="foo" attributeB="bar" attributeC="baz" attributeD="qux"></p>`;
let m;
while ((m = regex.exec(str)) !== null) {
// This is necessary to avoid infinite loops with zero-width matches
if (m.index === regex.lastIndex) {
regex.lastIndex++;
}
// The result can be accessed through the `m`-variable.
m.forEach((match, groupIndex) => {
console.log(`Found match, group ${groupIndex}: ${match}`);
});
}