I like this second approach of defining concat on Environment. Maybe it would be better to do concat = str.join or concat = native_concat instead of adding an extra method call.

I like this second approach of defining concat on Environment. Maybe it would be better to do concat = str.join or concat = native_concat instead of adding an extra method call.

Yeah, that is what I had initially but got TypeError: native_concat() takes 1 positional argument but 2 were given when used that way. Looking into it a bit more it appears that doing concat = partial(native_concat) works though, I have not looked into why yet.

Still playing with this, thanks for the feedback!

It's a problem with Python functions defined in C vs Python. str.join is a C function, but since native_concat is Python it requires concat = staticmethod(native_concat). It's a bit annoying, but I don't expect this to be a public API (beyond "assign this to make a custom rendering system").