Decode QString str(R"RX(...)RX") and explain what it is

Please_Help_me_D

Hi,

I started to learn QRegularExpression and I needed to write something like:

QString str("Quotes " are not allowed");

but as you can see I cannot simply put quote symbol " to QString.
But I can do it in the following way:

QString str(R"(Quotes " are not allowed)");

or:

QString str(R"RX(Quotes " are not allowed)RX");

Could someone explain what this R and RX mean in this case? How to google that?

jeremy_k

R""()"" is a C++ raw string literal. RX in the last example is used as a delimiter to avoid false detection of the end of the literal.

mrjj

Hi
As jeremy_k says it's a raw string literal which helps to avoid having to escape everything.
Before they came along one has to write it as

    QString str("\"Quotes \" are not allowed");

For regular expressions, this can fast becomes very clumsy and error-prone.

Please_Help_me_D

SGaist

Hi,

Just in case, Qt provides a helper tool to help you write your regexps and test them.