数えてみる

series を使用する。

(format t "~:{~a = ~d~%~}"
       (sort
        (series:collect
            (series:mapping
             ((file (series:scan (directory "**/*.lisp"))))
             (list file
                   (with-open-file (in file)
                     (series:collect-length
                      (series:choose-if
                       #'(lambda (line)
                           (ppcre:all-matches
                            #.(ppcre:create-scanner "def") line))
                       (series:scan-stream in #'read-line)))))))
        #'<= :key #'second))