;;; pp.el --- pretty printer for Emacs Lisp -*- lexical-binding: t -*- ;; Copyright (C) 1989, 1993, 2001-2021 Free Software Foundation, Inc. ;; Author: Randal Schwartz ;; 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 . ;;; 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))) ;;;###autoload (defun pp-buffer () "Prettify the current buffer with printed representation of a Lisp object." (interactive) (goto-char (point-min)) (while (not (eobp)) ;; (message "%06d" (- (point-max) (point))) (cond ((ignore-errors (down-list 1) t) (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) (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 (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) (setq-local 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 (elisp--eval-defun-1 (macroexpand (pp-last-sexp))) lexical-binding))) (pp-eval-expression (elisp--eval-defun-1 (macroexpand (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