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mirror of https://git.savannah.gnu.org/git/emacs.git synced 2024-12-22 10:26:20 +00:00
emacs/lisp/format-spec.el
Paul Eggert bc511a64f6 Prefer HTTPS to FTP and HTTP in documentation
Most of this change is to boilerplate commentary such as license URLs.
This change was prompted by ftp://ftp.gnu.org's going-away party,
planned for November.  Change these FTP URLs to https://ftp.gnu.org
instead.  Make similar changes for URLs to other organizations moving
away from FTP.  Also, change HTTP to HTTPS for URLs to gnu.org and
fsf.org when this works, as this will further help defend against
man-in-the-middle attacks (for this part I omitted the MS-DOS and
MS-Windows sources and the test tarballs to keep the workload down).
HTTPS is not fully working to lists.gnu.org so I left those URLs alone
for now.
2017-09-13 15:54:37 -07:00

80 lines
2.7 KiB
EmacsLisp

;;; format-spec.el --- functions for formatting arbitrary formatting strings
;; Copyright (C) 1999-2017 Free Software Foundation, Inc.
;; Author: Lars Magne Ingebrigtsen <larsi@gnus.org>
;; Keywords: tools
;; 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:
(eval-when-compile (require 'cl))
(defun format-spec (format specification)
"Return a string based on FORMAT and SPECIFICATION.
FORMAT is a string containing `format'-like specs like \"bash %u %k\",
while SPECIFICATION is an alist mapping from format spec characters
to values. Any text properties on a %-spec itself are propagated to
the text that it generates."
(with-temp-buffer
(insert format)
(goto-char (point-min))
(while (search-forward "%" nil t)
(cond
;; Quoted percent sign.
((eq (char-after) ?%)
(delete-char 1))
;; Valid format spec.
((looking-at "\\([-0-9.]*\\)\\([a-zA-Z]\\)")
(let* ((num (match-string 1))
(spec (string-to-char (match-string 2)))
(val (assq spec specification)))
(unless val
(error "Invalid format character: `%%%c'" spec))
(setq val (cdr val))
;; Pad result to desired length.
(let ((text (format (concat "%" num "s") val)))
;; Insert first, to preserve text properties.
(insert-and-inherit text)
;; Delete the specifier body.
(delete-region (+ (match-beginning 0) (length text))
(+ (match-end 0) (length text)))
;; Delete the percent sign.
(delete-region (1- (match-beginning 0)) (match-beginning 0)))))
;; Signal an error on bogus format strings.
(t
(error "Invalid format string"))))
(buffer-string)))
(defun format-spec-make (&rest pairs)
"Return an alist suitable for use in `format-spec' based on PAIRS.
PAIRS is a list where every other element is a character and a value,
starting with a character."
(let (alist)
(while pairs
(unless (cdr pairs)
(error "Invalid list of pairs"))
(push (cons (car pairs) (cadr pairs)) alist)
(setq pairs (cddr pairs)))
(nreverse alist)))
(provide 'format-spec)
;;; format-spec.el ends here