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?

Answer 1

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

Answer 2

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))