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| | ;;; pp.el --- pretty printer for Emacs Lisp -*- lexical-binding: t -*-
;; Copyright (C) 1989, 1993, 2001-2019 Free Software Foundation, Inc.
;; Author: Randal Schwartz <merlyn@stonehenge.com>
;; Keywords: lisp
;; This file is part of GNU Emacs.
;; GNU Emacs is free software: you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation, either version 3 of the License, or
;; (at your option) any later version.
;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;; GNU General Public License for more details.
;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs. If not, see <https://www.gnu.org/licenses/>.
;;; Commentary:
;;; Code:
(defvar font-lock-verbose)
(defgroup pp nil
"Pretty printer for Emacs Lisp."
:prefix "pp-"
:group 'lisp)
(defcustom pp-escape-newlines t
"Value of `print-escape-newlines' used by pp-* functions."
:type 'boolean
:group 'pp)
;;;###autoload
(defun pp-to-string (object)
"Return a string containing the pretty-printed representation of OBJECT.
OBJECT can be any Lisp object. Quoting characters are used as needed
to make output that `read' can handle, whenever this is possible."
(with-temp-buffer
(lisp-mode-variables nil)
(set-syntax-table emacs-lisp-mode-syntax-table)
(let ((print-escape-newlines pp-escape-newlines)
(print-quoted t))
(prin1 object (current-buffer)))
(pp-buffer)
(buffer-string)))
(defun pp--long-line ()
"Cut the line before point and before `fill-column' if needed."
;; FIXME: This still leaves lines longer than fill-column because
;; When pp-buffer calls us, the text is flush-left rather than
;; properly indented, so (current-column) is not the real column at
;; which the text will end up.
(let ((end (point)))
(when (> (current-column) fill-column)
(forward-line 0)
(let ((last nil))
(while (progn
(skip-syntax-forward "^\"< \\")
(skip-syntax-forward " ")
(and (< (point) end)
(or (< (current-column) fill-column)
(null last))))
(setq last (point))
(pcase (char-syntax (char-after))
(?\\ (forward-char 2))
(?\" (forward-sexp 1))
(?\< (end-of-line))))
(when last
(goto-char last)
(skip-syntax-backward " ")
(delete-region (point) last)
(insert "\n"))))))
;;;###autoload
(defun pp-buffer ()
"Prettify the current buffer with printed representation of a Lisp object."
(goto-char (point-min))
(while (not (eobp))
;; (message "%06d" (- (point-max) (point)))
(cond
((ignore-errors (down-list 1) t)
(pp--long-line)
(save-excursion
(backward-char 1)
(skip-chars-backward "'`#^")
(when (and (not (bobp)) (memq (char-before) '(?\s ?\t ?\n)))
(delete-region
(point)
(progn (skip-chars-backward " \t\n") (point)))
(insert "\n"))))
((ignore-errors (up-list 1) t)
(pp--long-line)
(skip-syntax-forward ")")
(delete-region
(point)
(progn (skip-chars-forward " \t\n") (point)))
(insert ?\n))
(t (goto-char (point-max)))))
(goto-char (point-min))
(indent-sexp))
;;;###autoload
(defun pp (object &optional stream)
"Output the pretty-printed representation of OBJECT, any Lisp object.
Quoting characters are printed as needed to make output that `read'
can handle, whenever this is possible.
Output stream is STREAM, or value of `standard-output' (which see)."
(princ (pp-to-string object) (or stream standard-output)))
(defun pp-display-expression (expression out-buffer-name)
"Prettify and display EXPRESSION in an appropriate way, depending on length.
If a temporary buffer is needed for representation, it will be named
after OUT-BUFFER-NAME."
(let* ((old-show-function temp-buffer-show-function)
;; Use this function to display the buffer.
;; This function either decides not to display it at all
;; or displays it in the usual way.
(temp-buffer-show-function
(function
(lambda (buf)
(with-current-buffer buf
(goto-char (point-min))
(end-of-line 1)
(if (or (< (1+ (point)) (point-max))
(>= (- (point) (point-min)) (frame-width)))
(let ((temp-buffer-show-function old-show-function)
(old-selected (selected-window))
(window (display-buffer buf)))
(goto-char (point-min)) ; expected by some hooks ...
(make-frame-visible (window-frame window))
(unwind-protect
(progn
(select-window window)
(run-hooks 'temp-buffer-show-hook))
(when (window-live-p old-selected)
(select-window old-selected))
(message "See buffer %s." out-buffer-name)))
(message "%s" (buffer-substring (point-min) (point)))
))))))
(with-output-to-temp-buffer out-buffer-name
(pp expression)
(with-current-buffer standard-output
(emacs-lisp-mode)
(setq buffer-read-only nil)
(set (make-local-variable 'font-lock-verbose) nil)))))
;;;###autoload
(defun pp-eval-expression (expression)
"Evaluate EXPRESSION and pretty-print its value.
Also add the value to the front of the list in the variable `values'."
(interactive
(list (read--expression "Eval: ")))
(message "Evaluating...")
(push (eval expression lexical-binding) values)
(pp-display-expression (car values) "*Pp Eval Output*"))
;;;###autoload
(defun pp-macroexpand-expression (expression)
"Macroexpand EXPRESSION and pretty-print its value."
(interactive
(list (read--expression "Macroexpand: ")))
(pp-display-expression (macroexpand-1 expression) "*Pp Macroexpand Output*"))
(defun pp-last-sexp ()
"Read sexp before point. Ignores leading comment characters."
(with-syntax-table emacs-lisp-mode-syntax-table
(let ((pt (point)))
(save-excursion
(forward-sexp -1)
(read
;; If first line is commented, ignore all leading comments:
(if (save-excursion (beginning-of-line) (looking-at-p "[ \t]*;"))
(let ((exp (buffer-substring (point) pt))
(start nil))
(while (string-match "\n[ \t]*;+" exp start)
(setq start (1+ (match-beginning 0))
exp (concat (substring exp 0 start)
(substring exp (match-end 0)))))
exp)
(current-buffer)))))))
;;;###autoload
(defun pp-eval-last-sexp (arg)
"Run `pp-eval-expression' on sexp before point.
With argument, pretty-print output into current buffer.
Ignores leading comment characters."
(interactive "P")
(if arg
(insert (pp-to-string (eval (pp-last-sexp) lexical-binding)))
(pp-eval-expression (pp-last-sexp))))
;;;###autoload
(defun pp-macroexpand-last-sexp (arg)
"Run `pp-macroexpand-expression' on sexp before point.
With argument, pretty-print output into current buffer.
Ignores leading comment characters."
(interactive "P")
(if arg
(insert (pp-to-string (macroexpand-1 (pp-last-sexp))))
(pp-macroexpand-expression (pp-last-sexp))))
(provide 'pp) ; so (require 'pp) works
;;; pp.el ends here
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