1 ;; pp.el --- pretty printer for Emacs Lisp
2 ;; Copyright (C) 1989, 1993 Free Software Foundation, Inc.
4 ;; Author: Randal Schwartz <merlyn@ora.com>
6 ;; This file is part of GNU Emacs.
8 ;; GNU Emacs is free software; you can redistribute it and/or modify
9 ;; it under the terms of the GNU General Public License as published by
10 ;; the Free Software Foundation; either version 2, or (at your option)
13 ;; GNU Emacs is distributed in the hope that it will be useful,
14 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
15 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 ;; GNU General Public License for more details.
18 ;; You should have received a copy of the GNU General Public License
19 ;; along with GNU Emacs; see the file COPYING. If not, write to
20 ;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
24 (defvar pp-escape-newlines t
25 "*Value of print-escape-newlines used by pp-* functions.")
27 (defun pp-to-string (object)
28 "Return a string containing the pretty-printed representation of OBJECT,
29 any Lisp object. Quoting characters are used when needed to make output
30 that `read' can handle, whenever this is possible."
32 (set-buffer (generate-new-buffer " pp-to-string"))
36 (let ((print-escape-newlines pp-escape-newlines))
37 (prin1 object (current-buffer)))
38 (goto-char (point-min))
40 ;; (message "%06d" (- (point-max) (point)))
43 (while (looking-at "\\s(")
45 ((and (looking-at "\\(quote[ \t]+\\)\\([^.)]\\)")
46 (> (match-beginning 1) 1)
47 (= ?\( (char-after (1- (match-beginning 1))))
48 ;; Make sure this is a two-element list.
50 (goto-char (match-beginning 2))
52 ;; (looking-at "[ \t]*\)")
53 ;; Avoid mucking with match-data; does this test work?
54 (char-equal ?\) (char-after (point)))))
55 ;; -1 gets the paren preceding the quote as well.
56 (delete-region (1- (match-beginning 1)) (match-end 1))
59 (if (looking-at "[ \t]*\)")
60 (delete-region (match-beginning 0) (match-end 0))
61 (error "Malformed quote"))
63 ((condition-case err-var
64 (prog1 t (down-list 1))
67 (skip-chars-backward " \t")
70 (progn (skip-chars-forward " \t") (point)))
71 (if (not (char-equal ?' (char-after (1- (point)))))
73 ((condition-case err-var
76 (while (looking-at "\\s)")
78 (skip-chars-backward " \t")
81 (progn (skip-chars-forward " \t") (point)))
82 (if (not (char-equal ?' (char-after (1- (point)))))
84 (t (goto-char (point-max)))))
85 (goto-char (point-min))
88 (kill-buffer (current-buffer)))))
91 (defun pp (object &optional stream)
92 "Output the pretty-printed representation of OBJECT, any Lisp object.
93 Quoting characters are printed when needed to make output that `read'
94 can handle, whenever this is possible.
95 Output stream is STREAM, or value of `standard-output' (which see)."
96 (princ (pp-to-string object) (or stream standard-output)))
99 (defun pp-eval-expression (expression)
100 "Evaluate EXPRESSION and pretty-print value into a new display buffer.
101 If the pretty-printed value fits on one line, the message line is used
102 instead. Value is also consed on to front of variable values 's
104 (interactive "xPp-eval: ")
105 (setq values (cons (eval expression) values))
106 (let* ((old-show-hook
107 (or (let ((sym (if (> (string-to-int emacs-version) 18)
108 'temp-buffer-show-function
109 'temp-buffer-show-hook)))
110 (and (boundp 'sym) (symbol-value sym)))
112 (temp-buffer-show-hook
117 (goto-char (point-min))
119 (if (or (< (1+ (point)) (point-max))
120 (>= (- (point) (point-min)) (screen-width)))
122 (goto-char (point-min)) ; expected by some hooks ...
123 (funcall old-show-hook buf))
124 (message "%s" (buffer-substring (point-min) (point)))
125 (delete-windows-on buf) ; no need to kill it
127 (temp-buffer-show-function temp-buffer-show-hook)) ; emacs19 name
128 (with-output-to-temp-buffer "*Pp Eval Output*"
131 (set-buffer "*Pp Eval Output*")
135 (defun pp-eval-last-sexp (arg)
136 "Run `pp-eval-expression' on sexp before point (which see).
137 With argument, pretty-print output into current buffer.
138 Ignores leading comment characters."
140 (let ((stab (syntax-table)) (pt (point)) start exp)
141 (set-syntax-table emacs-lisp-mode-syntax-table)
144 ;; If first line is commented, ignore all leading comments:
145 (if (save-excursion (beginning-of-line) (looking-at "[ \t]*;"))
147 (setq exp (buffer-substring (point) pt))
148 (while (string-match "\n[ \t]*;+" exp start)
149 (setq start (1+ (match-beginning 0))
150 exp (concat (substring exp 0 start)
151 (substring exp (match-end 0)))))
152 (setq exp (read exp)))
153 (setq exp (read (current-buffer)))))
154 (set-syntax-table stab)
156 (insert (pp-to-string (eval exp)))
157 (pp-eval-expression exp))))
159 ;;; Test cases for quote
160 ;; (pp-eval-expression ''(quote quote))
161 ;; (pp-eval-expression ''((quote a) (quote b)))
162 ;; (pp-eval-expression ''('a 'b)) ; same as above
163 ;; (pp-eval-expression ''((quote (quote quote)) (quote quote)))
164 ;; These do not satisfy the quote test.
165 ;; (pp-eval-expression ''quote)
166 ;; (pp-eval-expression ''(quote))
167 ;; (pp-eval-expression ''(quote . quote))
168 ;; (pp-eval-expression ''(quote a b))
169 ;; (pp-eval-expression ''(quotefoo))
170 ;; (pp-eval-expression ''(a b))
172 (provide 'pp) ; so (require 'pp) works