C++ templates also aren't general purpose macros. For example, in Rust you can write a macro that takes an expression `e` and replaces it with `e + 1`.

However, I believe you can't do that with C++ templates. C++ template parameters can be types or primitive values, but not expressions. And the body of a template has to be some sort of declaration, e.g. a function definition or struct definition, but not an expression or statement.