I might go to hell for comparing C++ templates to Lisp macros, but the line `class sorter : binary_function<product,product,bool> {` is basically mapping `first_argument_type` and `second_argument_type` to `product`, and the result_type to `bool`. So it returns a boolean, depending on if the first parameter's second part is bigger than the second parameter's second part.
`pair<string,int> = make_pair("hi", 10)` is just like a `("hi" . 10)` in Scheme.
This was meant to be a reply to @m455 but I have forgotten how to Mastodon. Sorry. Also funny that you mention it looks like Java because Java's `Map<String,Integer>` syntax is borrowed from C++ and implemented totally differently, but I also used it first in Java so I know what you mean. It's familiar but different.
