[suprfsat]

Template instantiation is a simple text replacement tool and it seems to work just fine.

[dig1]

I'm afraid it is not :) Template instantiation has way more rules than simple text replacement. Implicit instantiation is a story on its own, not counting that every compiler is free to implement own instantiation logic.

Someone said once that the truly portable thing between C++ compilers is only preprocessor :)

[tylerhou]

Because of compile-time evaluation and/or template pattern matching, C++ template instantiation is Turing complete. So it's basically as far away from "simple text replacement tool" as you could possibly be.

[mhh__]

https://github.com/dlang/dmd/blob/master/src/dmd/dtemplate.d

That must be why the implementation of D's templates, which are designed to be easier to implement than C++'s is at least 8337 lines?

edit: Clang's clocks in at about 11k lines (.cpp alone), I'm too scared to find out for GCC.

[formerly_proven]

GCC's cp/pt.c is around 30k lines. But I don't expect the implementation of templates to be this localized, sure, most of it is probably in that module, but a lot will be strewn about the code base, too.

[oblio]

Is that why templates have such user friendly error messages?