Extending struct to use struct fields

[ajuvercr]

Hi,
I was wondering how difficult it would be to enable templates like #[get("https://api.github.com/repos/{self.path}")].
This can be useful to not store URL's as const like the GITHUB example.

My usecase would be a bit more advanced, where a struct stores AUTH JWT's and adds the JWT as a header, which is stored in self.

What are your thoughts?