It took quite a while for Lisp to get "proper" lexical closures - not until Scheme & CL in the 1980s really, see, for example: http://www.paulgraham.com/thist.

It took quite a while for Lisp to get "proper" lexical closures - not until Scheme & CL in the 1980s really, see, for example: http://www.paulgraham.com/thist.html http://www.paulgraham.com/thist.html