1 ;;; pp.el --- pretty printer for Emacs Lisp
3 ;; Copyright (C) 1989, 1993 Free Software Foundation, Inc.
5 ;; Author: Randal Schwartz <merlyn@stonehenge.com>
7 ;; This file is part of GNU Emacs.
9 ;; GNU Emacs is free software; you can redistribute it and/or modify
10 ;; it under the terms of the GNU General Public License as published by
11 ;; the Free Software Foundation; either version 2, or (at your option)
14 ;; GNU Emacs is distributed in the hope that it will be useful,
15 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
16 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 ;; GNU General Public License for more details.
19 ;; You should have received a copy of the GNU General Public License
20 ;; along with GNU Emacs; see the file COPYING. If not, write to the
21 ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
22 ;; Boston, MA 02111-1307, USA.
26 (defvar pp-escape-newlines t
27 "*Value of print-escape-newlines used by pp-* functions.")
29 (defun pp-to-string (object)
30 "Return a string containing the pretty-printed representation of OBJECT,
31 any Lisp object. Quoting characters are used when needed to make output
32 that `read' can handle, whenever this is possible."
34 (set-buffer (generate-new-buffer " pp-to-string"))
37 (lisp-mode-variables t)
38 (let ((print-escape-newlines pp-escape-newlines))
39 (prin1 object (current-buffer)))
40 (goto-char (point-min))
42 ;; (message "%06d" (- (point-max) (point)))
44 ((looking-at "\\s(\\|#\\s(")
45 (while (looking-at "\\s(\\|#\\s(")
47 ((and (looking-at "\\(quote[ \t]+\\)\\([^.)]\\)")
48 (> (match-beginning 1) 1)
49 (= ?\( (char-after (1- (match-beginning 1))))
50 ;; Make sure this is a two-element list.
52 (goto-char (match-beginning 2))
54 ;; (looking-at "[ \t]*\)")
55 ;; Avoid mucking with match-data; does this test work?
56 (char-equal ?\) (char-after (point)))))
57 ;; -1 gets the paren preceding the quote as well.
58 (delete-region (1- (match-beginning 1)) (match-end 1))
61 (if (looking-at "[ \t]*\)")
62 (delete-region (match-beginning 0) (match-end 0))
63 (error "Malformed quote"))
65 ((condition-case err-var
66 (prog1 t (down-list 1))
69 (skip-chars-backward " \t")
72 (progn (skip-chars-forward " \t") (point)))
73 (if (not (char-equal ?' (char-after (1- (point)))))
75 ((condition-case err-var
78 (while (looking-at "\\s)")
80 (skip-chars-backward " \t")
83 (progn (skip-chars-forward " \t") (point)))
84 (if (not (char-equal ?' (char-after (1- (point)))))
86 (t (goto-char (point-max)))))
87 (goto-char (point-min))
90 (kill-buffer (current-buffer)))))
93 (defun pp (object &optional stream)
94 "Output the pretty-printed representation of OBJECT, any Lisp object.
95 Quoting characters are printed when needed to make output that `read'
96 can handle, whenever this is possible.
97 Output stream is STREAM, or value of `standard-output' (which see)."
98 (princ (pp-to-string object) (or stream standard-output)))
101 (defun pp-eval-expression (expression)
102 "Evaluate EXPRESSION and pretty-print value into a new display buffer.
103 If the pretty-printed value fits on one line, the message line is used
104 instead. Value is also consed on to front of variable values 's
106 (interactive "xPp-eval: ")
107 (setq values (cons (eval expression) values))
108 (let* ((old-show-function temp-buffer-show-function)
109 ;; Use this function to display the buffer.
110 ;; This function either decides not to display it at all
111 ;; or displays it in the usual way.
112 (temp-buffer-show-function
117 (goto-char (point-min))
119 (if (or (< (1+ (point)) (point-max))
120 (>= (- (point) (point-min)) (frame-width)))
121 (let ((temp-buffer-show-function old-show-function)
122 (old-selected (selected-window))
123 (window (display-buffer buf)))
124 (goto-char (point-min)) ; expected by some hooks ...
125 (make-frame-visible (window-frame window))
128 (select-window window)
129 (run-hooks 'temp-buffer-show-hook))
130 (select-window old-selected)))
131 (message "%s" (buffer-substring (point-min) (point)))
133 (with-output-to-temp-buffer "*Pp Eval Output*"
136 (set-buffer "*Pp Eval Output*")
138 (make-local-variable 'font-lock-verbose)
139 (setq font-lock-verbose nil))))
142 (defun pp-eval-last-sexp (arg)
143 "Run `pp-eval-expression' on sexp before point (which see).
144 With argument, pretty-print output into current buffer.
145 Ignores leading comment characters."
147 (let ((stab (syntax-table)) (pt (point)) start exp)
148 (set-syntax-table emacs-lisp-mode-syntax-table)
151 ;; If first line is commented, ignore all leading comments:
152 (if (save-excursion (beginning-of-line) (looking-at "[ \t]*;"))
154 (setq exp (buffer-substring (point) pt))
155 (while (string-match "\n[ \t]*;+" exp start)
156 (setq start (1+ (match-beginning 0))
157 exp (concat (substring exp 0 start)
158 (substring exp (match-end 0)))))
159 (setq exp (read exp)))
160 (setq exp (read (current-buffer)))))
161 (set-syntax-table stab)
163 (insert (pp-to-string (eval exp)))
164 (pp-eval-expression exp))))
166 ;;; Test cases for quote
167 ;; (pp-eval-expression ''(quote quote))
168 ;; (pp-eval-expression ''((quote a) (quote b)))
169 ;; (pp-eval-expression ''('a 'b)) ; same as above
170 ;; (pp-eval-expression ''((quote (quote quote)) (quote quote)))
171 ;; These do not satisfy the quote test.
172 ;; (pp-eval-expression ''quote)
173 ;; (pp-eval-expression ''(quote))
174 ;; (pp-eval-expression ''(quote . quote))
175 ;; (pp-eval-expression ''(quote a b))
176 ;; (pp-eval-expression ''(quotefoo))
177 ;; (pp-eval-expression ''(a b))
179 (provide 'pp) ; so (require 'pp) works