[kazinator]

Definitely. Lisp is a family of languages that has now existed for almost 70 years. There simply isn't one way that closures work in "Lisp". Some implementations of languages in the lisp family have compilers that have sophisticated ways of handling closures. They carefully classify what is or is not captured by closure (and what is shared with other closures and what is mutably shared), and try to guess whether a closure can escape from the environment where it's created. Different code generation strategies, and strategies for representing the environment, apply to different situations.