4.2 Tracing options

4.2.2 Evaluating forms without printing results

:eval-before

Trace keyword

: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

Trace keyword

: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.