Functon in function

[saitoib]

Hi all!

Sorry for the rudimentary question, but...

In Lisp, a lot of people define functions inside functions, is there an advantage over defining them outside functions?

I'm confused because I don't see this method in general programming.

Thank you.

[hak_vz · Accepted solution]

(defun main_function (parameter_1 / local_function local_variable)
(defun local_function ()

)
)

This way we create localized function that is part of main function so it can not affect some other code that may have functions or variables defined with same name. This is common practice in other languages, let say javascript.

When you create your code you can have outer function that when finished you make local. It is a good an proposed code writing practice. 

[saitoib]

Thank you very much.
I'm convinced.