The named capture groups `(?P<name>...)` and `(?'name'...)` are unimplemented. If these are implemented in CTRE's grammar then it will be closer to PCRE. ```C++ #include <ctre.hpp> int main(){ ctre::match<"(?<name>a)">; // These do not work ctre::match<"(?'name'a)">; ctre::match<"(?P<name>a)">; } ``` [Compiler explorer link](https://godbolt.org/z/jeacqhebo) ```regex (?'test1'test1)|(?<test2>test2)|(?P<test3>test3) ``` [Regex101 link](https://regex101.com/r/f9MIPv/1)