diff options
Diffstat (limited to 'lisp/emacs-lisp/pp.el')
| -rw-r--r-- | lisp/emacs-lisp/pp.el | 300 |
1 files changed, 247 insertions, 53 deletions
diff --git a/lisp/emacs-lisp/pp.el b/lisp/emacs-lisp/pp.el index e6e3cd6c6f4..a93e634c685 100644 --- a/lisp/emacs-lisp/pp.el +++ b/lisp/emacs-lisp/pp.el @@ -25,7 +25,6 @@ ;;; Code: (require 'cl-lib) -(defvar font-lock-verbose) (defgroup pp nil "Pretty printer for Emacs Lisp." @@ -52,53 +51,239 @@ Note that this could slow down `pp' considerably when formatting large lists." :type 'boolean :version "29.1") +(make-obsolete-variable 'pp-use-max-width 'pp-default-function "30.1") + +(defcustom pp-default-function #'pp-fill + ;; FIXME: The best pretty printer to use depends on the use-case + ;; so maybe we should allow callers to specify what they want (maybe with + ;; options like `fast', `compact', `code', `data', ...) and these + ;; can then be mapped to actual pretty-printing algorithms. + ;; Then again, callers can just directly call the corresponding function. + "Function that `pp' should dispatch to for pretty printing. +That function can be called in one of two ways: +- with a single argument, which it should insert and pretty-print at point. +- with two arguments which delimit a region containing Lisp sexps + which should be pretty-printed. +In both cases, the function can presume that the buffer is setup for +Lisp syntax." + :type '(choice + (const :tag "Fit within `fill-column'" pp-fill) + (const :tag "Emacs<29 algorithm, fast and good enough" pp-28) + (const :tag "Work hard for code (slow on large inputs)" + pp-emacs-lisp-code) + (const :tag "`pp-emacs-lisp-code' if `pp-use-max-width' else `pp-28'" + pp-29) + function) + :version "30.1") (defvar pp--inhibit-function-formatting nil) +;; There are basically two APIs for a pretty-printing function: +;; +;; - either the function takes an object (and prints it in addition to +;; prettifying it). +;; - or the function takes a region containing an already printed object +;; and prettifies its content. +;; +;; `pp--object' and `pp--region' are helper functions to convert one +;; API to the other. + + +(defun pp--object (object region-function) + "Pretty-print OBJECT at point. +The prettifying is done by REGION-FUNCTION which is +called with two positions as arguments and should fold lines +within that region. Returns the result as a string." + (let ((print-escape-newlines pp-escape-newlines) + (print-quoted t) + (beg (point))) + ;; FIXME: In many cases it would be preferable to use `cl-prin1' here. + (prin1 object (current-buffer)) + (funcall region-function beg (point)))) + +(defun pp--region (beg end object-function) + "Pretty-print the object(s) contained within BEG..END. +OBJECT-FUNCTION is called with a single object as argument +and should pretty print it at point into the current buffer." + (save-excursion + (with-restriction beg end + (goto-char (point-min)) + (while + (progn + ;; We'll throw away all the comments within objects, but let's + ;; try at least to preserve the comments between objects. + (forward-comment (point-max)) + (let ((beg (point)) + (object (ignore-error end-of-buffer + (list (read (current-buffer)))))) + (when (consp object) + (delete-region beg (point)) + (funcall object-function (car object)) + t))))))) + +(defun pp-29 (beg-or-sexp &optional end) ;FIXME: Better name? + "Prettify the current region with printed representation of a Lisp object. +Uses the pretty-printing algorithm that was standard in Emacs-29, +which, depending on `pp-use-max-width', will either use `pp-28' +or `pp-emacs-lisp-code'." + (if pp-use-max-width + (let ((pp--inhibit-function-formatting t)) ;FIXME: Why? + (pp-emacs-lisp-code beg-or-sexp end)) + (pp-28 beg-or-sexp end))) + ;;;###autoload -(defun pp-to-string (object) +(defun pp-to-string (object &optional pp-function) "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." - (if pp-use-max-width - (let ((pp--inhibit-function-formatting t)) - (with-temp-buffer - (pp-emacs-lisp-code object) - (buffer-string))) - (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)))) +to make output that `read' can handle, whenever this is possible. +Optional argument PP-FUNCTION overrides `pp-default-function'." + (with-temp-buffer + (lisp-mode-variables nil) + (set-syntax-table emacs-lisp-mode-syntax-table) + (funcall (or pp-function pp-default-function) object) + ;; Preserve old behavior of (usually) finishing with a newline. + (unless (bolp) (insert "\n")) + (buffer-string))) + +(defun pp--within-fill-column-p () + "Return non-nil if point is within `fill-column'." + ;; Try and make it O(fill-column) rather than O(current-column), + ;; so as to avoid major slowdowns on long lines. + ;; FIXME: This doesn't account for invisible text or `display' properties :-( + (and (save-excursion + (re-search-backward + "^\\|\n" (max (point-min) (- (point) fill-column)) t)) + (<= (current-column) fill-column))) + +(defun pp-fill (beg &optional end) + "Break lines in Lisp code between BEG and END so it fits within `fill-column'. +Presumes the current buffer has syntax and indentation properly +configured for that. +Designed under the assumption that the region occupies a single line, +tho it should also work if that's not the case. +Can also be called with a single argument, in which case +it inserts and pretty-prints that arg at point." + (interactive "r") + (if (null end) (pp--object beg #'pp-fill) + (goto-char beg) + (let ((end (copy-marker end t)) + (newline (lambda () + (skip-chars-forward ")]}") + (unless (save-excursion (skip-chars-forward " \t") (eolp)) + (insert "\n") + (indent-according-to-mode))))) + (while (progn (forward-comment (point-max)) + (< (point) end)) + (let ((beg (point)) + ;; Whether we're in front of an element with paired delimiters. + ;; Can be something funky like #'(lambda ..) or ,'#s(...) + ;; Or also #^[..]. + (paired (when (looking-at "['`,#]*[[:alpha:]^]*\\([({[\"]\\)") + (match-beginning 1)))) + ;; Go to the end of the sexp. + (goto-char (or (scan-sexps (or paired (point)) 1) end)) + (unless + (and + ;; The sexp is all on a single line. + (save-excursion (not (search-backward "\n" beg t))) + ;; And its end is within `fill-column'. + (or (pp--within-fill-column-p) + ;; If the end of the sexp is beyond `fill-column', + ;; try to move the sexp to its own line. + (and + (save-excursion + (goto-char beg) + (if (save-excursion (skip-chars-backward " \t({[',") + (bolp)) + ;; The sexp was already on its own line. + nil + (skip-chars-backward " \t") + (setq beg (copy-marker beg t)) + (if paired (setq paired (copy-marker paired t))) + ;; We could try to undo this insertion if it + ;; doesn't reduce the indentation depth, but I'm + ;; not sure it's worth the trouble. + (insert "\n") (indent-according-to-mode) + t)) + ;; Check again if we moved the whole exp to a new line. + (pp--within-fill-column-p)))) + ;; The sexp is spread over several lines, and/or its end is + ;; (still) beyond `fill-column'. + (when (and paired (not (eq ?\" (char-after paired)))) + ;; The sexp has sub-parts, so let's try and spread + ;; them over several lines. + (save-excursion + (goto-char beg) + (when (looking-at "(\\([^][()\" \t\n;']+\\)") + ;; Inside an expression of the form (SYM ARG1 + ;; ARG2 ... ARGn) where SYM has a `lisp-indent-function' + ;; property that's a number, insert a newline after + ;; the corresponding ARGi, because it tends to lead to + ;; more natural and less indented code. + (let* ((sym (intern-soft (match-string 1))) + (lif (and sym (get sym 'lisp-indent-function)))) + (if (eq lif 'defun) (setq lif 2)) + (when (natnump lif) + (goto-char (match-end 0)) + ;; Do nothing if there aren't enough args. + (ignore-error scan-error + (forward-sexp lif) + (funcall newline)))))) + (save-excursion + (pp-fill (1+ paired) (1- (point))))) + ;; Now the sexp either ends beyond `fill-column' or is + ;; spread over several lines (or both). Either way, the + ;; rest of the line should be moved to its own line. + (funcall newline))))))) ;;;###autoload (defun pp-buffer () "Prettify the current buffer with printed representation of a Lisp object." (interactive) - (goto-char (point-min)) - (while (not (eobp)) - (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))) + ;; The old code used `indent-sexp' which mostly works "anywhere", + ;; so let's make sure we also work right in buffers that aren't + ;; setup specifically for Lisp. + (if (and (eq (syntax-table) emacs-lisp-mode-syntax-table) + (eq indent-line-function #'lisp-indent-line)) + (funcall pp-default-function (point-min) (point-max)) + (with-syntax-table emacs-lisp-mode-syntax-table + (let ((indent-line-function #'lisp-indent-line)) + (funcall pp-default-function (point-min) (point-max))))) + ;; Preserve old behavior of (usually) finishing with a newline and + ;; with point at BOB. + (goto-char (point-max)) + (unless (bolp) (insert "\n")) + (goto-char (point-min))) + +(defun pp-28 (beg &optional end) ;FIXME: Better name? + "Prettify the current region with printed representation of a Lisp object. +Uses the pretty-printing algorithm that was standard before Emacs-30. +Non-interactively can also be called with a single argument, in which +case that argument will be inserted pretty-printed at point." + (interactive "r") + (if (null end) (pp--object beg #'pp-29) + (with-restriction beg end + (goto-char (point-min)) + (while (not (eobp)) + (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-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)) + (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) @@ -106,14 +291,20 @@ to make output that `read' can handle, whenever this is possible." Quoting characters are printed as needed to make output that `read' can handle, whenever this is possible. -This function does not apply special formatting rules for Emacs -Lisp code. See `pp-emacs-lisp-code' instead. - -By default, this function won't limit the line length of lists -and vectors. Bind `pp-use-max-width' to a non-nil value to do so. +Uses the pretty-printing code specified in `pp-default-function'. Output stream is STREAM, or value of `standard-output' (which see)." - (princ (pp-to-string object) (or stream standard-output))) + (cond + ((and (eq (or stream standard-output) (current-buffer)) + ;; Make sure the current buffer is setup sanely. + (eq (syntax-table) emacs-lisp-mode-syntax-table) + (eq indent-line-function #'lisp-indent-line)) + ;; Skip the buffer->string->buffer middle man. + (funcall pp-default-function object) + ;; Preserve old behavior of (usually) finishing with a newline. + (unless (bolp) (insert "\n"))) + (t + (princ (pp-to-string object) (or stream standard-output))))) ;;;###autoload (defun pp-display-expression (expression out-buffer-name &optional lisp) @@ -220,21 +411,24 @@ Ignores leading comment characters." (pp-macroexpand-expression (pp-last-sexp)))) ;;;###autoload -(defun pp-emacs-lisp-code (sexp) +(defun pp-emacs-lisp-code (sexp &optional end) "Insert SEXP into the current buffer, formatted as Emacs Lisp code. Use the `pp-max-width' variable to control the desired line length. -Note that this could be slow for large SEXPs." +Note that this could be slow for large SEXPs. +Can also be called with two arguments, in which case they're taken to be +the bounds of a region containing Lisp code to pretty-print." (require 'edebug) - (let ((obuf (current-buffer))) - (with-temp-buffer - (emacs-lisp-mode) - (pp--insert-lisp sexp) - (insert "\n") - (goto-char (point-min)) - (indent-sexp) - (while (re-search-forward " +$" nil t) - (replace-match "")) - (insert-into-buffer obuf)))) + (if end (pp--region sexp end #'pp-emacs-lisp-code) + (let ((obuf (current-buffer))) + (with-temp-buffer + (emacs-lisp-mode) + (pp--insert-lisp sexp) + (insert "\n") + (goto-char (point-min)) + (indent-sexp) + (while (re-search-forward " +$" nil t) + (replace-match "")) + (insert-into-buffer obuf))))) (defun pp--insert-lisp (sexp) (cl-case (type-of sexp) |