info (obj &amp;key (stream t))
             (with-output-to-stream:with-output-to-stream (s stream)
               (write-string &quot;INFO &quot; s)
               (write obj :stream s)
               (terpri s)))

;; Here is we return result as a string:
POFTHEDAY&gt; (log-info 100500 :stream nil)
&quot;INFO 100500
&quot;

;; This will output to *standard-output*:
POFTHEDAY&gt; (log-info 100500 :stream t)
INFO 100500
NIL

;; But you can pass any stream as the argument:
POFTHEDAY&gt; (log-info 100500 :stre