CCL has an inspector, an interactive tool to let you look at, and in some cases modify, Lisp objects. To inspect a Lisp object, call the function INSPECT on the object. This displays the object, showing its contents as a sequence of numbered "items". If there are a lot of items (e.g. a large array) , they're displayed in "pages", i.e. groups that you can scroll up and down through. (Each "page" is 20 lines.)
It enters a read-eval-print loop that understands the following top-level commands:
Inspect the N'th item, entering the inspector recursively.
Exit the current inspector level.
Show (display) the object being inspected, again.
Show next "page" of the object
Show previous "page" of the object
Show first "page" of the object
(:s N V)
Set the value of the N'th item to V, where that can be done.
If you type in an ordinary Lisp form, it is evaluated and printed. The variable ccl::@ is bound to the object being inspected.
In the :i and :s commands, N is not evaluated, and in the :s command, V is not evaluated. (You can use the #. reader macro if you do want to get something evaluated in those positions.)