:eval-before list-of-forms
This option allows you to supply a list of forms for evaluation upon entering the traced function. The forms are evaluated after printing out the arguments to the function, but unlike :before
their results are not printed.
:eval-after list-of-forms
This option allows you to supply a list of forms for evaluation upon leaving the traced function. The forms are evaluated after printing out the results of the function call, but unlike :after
their results are not printed.