PPRINT in Emacs Lisp?

Question

Emacs Lisp does not seem to have a PPRINT function. How do you pretty print an S-EXP in elisp the way you can in Common Lisp?

I see cl-prettyprint will print to the current buffer. I am looking for something that works with an output stream like Common Lisp's PPRINT does. — anthonyf, Aug 23 '10 at 22:17

Jérôme Radix · Answer 1 · 2010-08-24T07:34:51.347

27

Use the pp library which is part of GNU Emacs. For example you can use pp-macroexpand-last-sexp for prettifying an sexp.

edited Aug 24 '10 at 07:34

answered Aug 24 '10 at 07:20

Jérôme Radix

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Easiest way is to just use `(pp object)` – Andrzej Pronobis Mar 13 '16 at 18:11
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My... that library looks familiar. Oh yeah, I wrote it. :) – Randal Schwartz Jan 24 '17 at 04:28

score 13 · Answer 2 · answered Aug 23 '10 at 23:00

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Assuming that the result of cl-prettyprint is good enough for you, here's how to get its output in a stream.

(defun pprint (form &optional output-stream)
  (princ (with-temp-buffer
           (cl-prettyprint form)
           (buffer-string))
         output-stream))

answered Aug 23 '10 at 23:00

Gilles 'SO- stop being evil'

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When you are a buffer how can you get cl-prettyprint to replace a defun with its pretty printed version? Can – vfclists Oct 31 '20 at 10:45
Thanks for this. It's weird to me that `cl-prettyprint` doesn't return a string in the first place. – Chris Clark Jun 01 '21 at 17:18

PPRINT in Emacs Lisp?

2 Answers2