| 1 | ;;; format-spec.el --- functions for formatting arbitrary formatting strings |
| 2 | |
| 3 | ;; Copyright (C) 1999-2013 Free Software Foundation, Inc. |
| 4 | |
| 5 | ;; Author: Lars Magne Ingebrigtsen <larsi@gnus.org> |
| 6 | ;; Keywords: tools |
| 7 | |
| 8 | ;; This file is part of GNU Emacs. |
| 9 | |
| 10 | ;; GNU Emacs is free software: you can redistribute it and/or modify |
| 11 | ;; it under the terms of the GNU General Public License as published by |
| 12 | ;; the Free Software Foundation, either version 3 of the License, or |
| 13 | ;; (at your option) any later version. |
| 14 | |
| 15 | ;; GNU Emacs is distributed in the hope that it will be useful, |
| 16 | ;; but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 17 | ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 18 | ;; GNU General Public License for more details. |
| 19 | |
| 20 | ;; You should have received a copy of the GNU General Public License |
| 21 | ;; along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>. |
| 22 | |
| 23 | ;;; Commentary: |
| 24 | |
| 25 | ;;; Code: |
| 26 | |
| 27 | (eval-when-compile (require 'cl)) |
| 28 | |
| 29 | (defun format-spec (format specification) |
| 30 | "Return a string based on FORMAT and SPECIFICATION. |
| 31 | FORMAT is a string containing `format'-like specs like \"bash %u %k\", |
| 32 | while SPECIFICATION is an alist mapping from format spec characters |
| 33 | to values. Any text properties on a %-spec itself are propagated to |
| 34 | the text that it generates." |
| 35 | (with-temp-buffer |
| 36 | (insert format) |
| 37 | (goto-char (point-min)) |
| 38 | (while (search-forward "%" nil t) |
| 39 | (cond |
| 40 | ;; Quoted percent sign. |
| 41 | ((eq (char-after) ?%) |
| 42 | (delete-char 1)) |
| 43 | ;; Valid format spec. |
| 44 | ((looking-at "\\([-0-9.]*\\)\\([a-zA-Z]\\)") |
| 45 | (let* ((num (match-string 1)) |
| 46 | (spec (string-to-char (match-string 2))) |
| 47 | (val (cdr (assq spec specification)))) |
| 48 | (unless val |
| 49 | (error "Invalid format character: `%%%c'" spec)) |
| 50 | ;; Pad result to desired length. |
| 51 | (let ((text (format (concat "%" num "s") val))) |
| 52 | ;; Insert first, to preserve text properties. |
| 53 | (insert-and-inherit text) |
| 54 | ;; Delete the specifier body. |
| 55 | (delete-region (+ (match-beginning 0) (length text)) |
| 56 | (+ (match-end 0) (length text))) |
| 57 | ;; Delete the percent sign. |
| 58 | (delete-region (1- (match-beginning 0)) (match-beginning 0))))) |
| 59 | ;; Signal an error on bogus format strings. |
| 60 | (t |
| 61 | (error "Invalid format string")))) |
| 62 | (buffer-string))) |
| 63 | |
| 64 | (defun format-spec-make (&rest pairs) |
| 65 | "Return an alist suitable for use in `format-spec' based on PAIRS. |
| 66 | PAIRS is a list where every other element is a character and a value, |
| 67 | starting with a character." |
| 68 | (let (alist) |
| 69 | (while pairs |
| 70 | (unless (cdr pairs) |
| 71 | (error "Invalid list of pairs")) |
| 72 | (push (cons (car pairs) (cadr pairs)) alist) |
| 73 | (setq pairs (cddr pairs))) |
| 74 | (nreverse alist))) |
| 75 | |
| 76 | (provide 'format-spec) |
| 77 | |
| 78 | ;;; format-spec.el ends here |