while loop, you can work on each of a list of files
with recursion. A recursive version of
is short and simple.
The recursive function has the usual parts: the ‘do-again-test’, the
‘next-step-expression’, and the recursive call. The ‘do-again-test’
determines whether the function should call itself again, which it
will do if the
list-of-files contains any remaining elements;
the ‘next-step-expression’ resets the
list-of-files to the
CDR of itself, so eventually the list will be empty; and the
recursive call calls itself on the shorter list. The complete
function is shorter than this description!
(defun recursive-lengths-list-many-files (list-of-files) "Return list of lengths of each defun in LIST-OF-FILES." (if list-of-files ; do-again-test (append (lengths-list-file (expand-file-name (car list-of-files))) (recursive-lengths-list-many-files (cdr list-of-files)))))
In a sentence, the function returns the lengths’ list for the first of
list-of-files appended to the result of calling itself on
the rest of the
Here is a test of
recursive-lengths-list-many-files, along with
the results of running
lengths-list-file on each of the files
lengths-list-file, if necessary, and then evaluate the
following expressions. You may need to change the files’ pathnames;
those here work when this Info file and the Emacs sources are located
in their customary places. To change the expressions, copy them to
the *scratch* buffer, edit them, and then evaluate them.
The results are shown after the ‘⇒’. (These results are for files from Emacs version 22.1.1; files from other versions of Emacs may produce different results.)
(cd "/usr/local/share/emacs/22.1.1/") (lengths-list-file "./lisp/macros.el") ⇒ (283 263 480 90)
(lengths-list-file "./lisp/mail/mailalias.el") ⇒ (38 32 29 95 178 180 321 218 324)
(lengths-list-file "./lisp/makesum.el") ⇒ (85 181)
(recursive-lengths-list-many-files '("./lisp/macros.el" "./lisp/mail/mailalias.el" "./lisp/makesum.el")) ⇒ (283 263 480 90 38 32 29 95 178 180 321 218 324 85 181)
recursive-lengths-list-many-files function produces the
output we want.
The next step is to prepare the data in the list for display in a graph.