### 1.5 Interacting with the Lisp process ¶

Since StumpWM is a Lisp program, there is a way for you to evaluate Lisp code directly, on the same Lisp process that StumpWM is running on. Type `C-t :` and an input box will appear. Then type some Lisp expression.

When you call `eval` this way, you will be in the STUMPWM-USER package, which imports all the exported symbols from the main STUMPWM package.

`*mode-line-border-width*`

  Reads the value of *mode-line-border-width*.

`(setf *mode-line-border-width* 3)`

  Sets the variable *mode-line-border-width* to 3.

`(set-prefix-key (kbd "C-M-H-s-z"))`

  Calls the `set-prefix-key` function (and sets a new keyboard prefix)