5.9.5 Local Functions

The defun special form allows globally-accessible functions to be defined. It is often desirable to declare functions local to the current lexical environment. The let and let* special form that were introduced earlier allow this since named functions are simply functional values stored in variables.

For example,

(let
    ((temporary-function (lambda (x)
                           (+ x 42))))
  …
  (temporary-function 20)
  …