boost::spirit and boost::qi are similar uses of deep secrets of template magic. They work nicely, until you make your first minor error and have to understand the whole machinery to get what's wrong.
Maybe someday we'll have a language that is efficient and also allows creating efficient and usable DSLs. C++ ain't it.
Assuming you're talking about Concepts, I've heard Andrei Alexandrescu, for example, challenge that hope [0], but I'd be happy to hear this has been fixed.
Maybe someday we'll have a language that is efficient and also allows creating efficient and usable DSLs. C++ ain't it.
Edit: perhaps D would actually be that language?