Common Lisp has lexical AND dynamic scoping. This is very nice with constants. A function can make a hard dependency on standard out for example. If I change t

Common Lisp has lexical AND dynamic scoping. This is very nice with constants. A function can make a hard dependency on standard out for example. If I change that value locally then call the function, it will operate as expected while everything else using that variable name will continue using their own expected values too. Lexical scoping would instead require passing that value in every time it is used.