rbj@nav.icst.nbs.GOV (Root Boy Jim) (09/13/88)
Why, a pretty printer, of course!
I have often wished to see the definitions of functions, especially my
own, but no standard way exists, possibly because most functions end up
getting byte compiled, and you can always edit the text in a buffer anyway.
Nevertheless, I wrote this little gem. It pretty prints just about anything
that can be a function definition. Interactively, it requires a symbol
with a function definition, but if called from elisp it will look in
the symbol's value cell if its function definition is void. This can be
used to print keymaps as in (pp 'global-map).
Given a function `f', it leaves the output in buffer `*f*' in a form
suitable to the lisp reader that will redefine the function in most
cases. With a prefix argument, you can be a voyeur. As an example of
its output, I am posting the output of running it upon itself. Enjoy.
(defun pp (function &optional verbose) "Pretty Print FUNCTION"
(interactive "aPretty Print:
P")
(let*
((name
(symbol-name function))
(buffer
(concat "*" name "*")))
(with-output-to-temp-buffer buffer
(select-window
(display-buffer buffer))
(set-buffer buffer)
(emacs-lisp-mode)
(erase-buffer)
(prin1
(if
(fboundp function)
(symbol-function function)
(symbol-value function)))
(goto-char 1)
(if verbose
(sit-for 0))
(cond
((looking-at "(macro lambda")
(replace-match "(defmacro ")
(insert name)
(forward-sexp 1))
((looking-at "(lambda")
(replace-match "(defun ")
(insert name)
(forward-sexp 1))
(t
(insert-parentheses 1)
(insert "fset '" name " ")))
(while
(not
(eobp))
(if verbose
(sit-for 0))
(cond
((looking-at "[][()]")
(skip-chars-forward "][()"))
((looking-at " [([]")
(delete-char 1)
(insert 10))
(t
(forward-sexp))))
(goto-char 1)
(indent-sexp))))
(Root Boy) Jim Cottrell <rbj@icst-cmr.arpa>
National Institute of Standards and Technology
Flamer's Hotline: (301) 975-5688
The opinions expressed are solely my own
and do not reflect NIST policy or agreement
Careful with that VAX Eugene!