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1 | ;;; float-sup.el --- define some constants useful for floating point numbers. |
2 | ||
d59c3137 | 3 | ;; Copyright (C) 1985, 1986, 1987, 2001, 2002, 2003, 2004, |
8b72699e | 4 | ;; 2005, 2006, 2007, 2008 Free Software Foundation, Inc. |
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5 | |
6 | ;; Maintainer: FSF | |
7 | ;; Keywords: internal | |
8 | ||
9 | ;; This file is part of GNU Emacs. | |
10 | ||
11 | ;; GNU Emacs is free software; you can redistribute it and/or modify | |
12 | ;; it under the terms of the GNU General Public License as published by | |
e0085d62 | 13 | ;; the Free Software Foundation; either version 3, or (at your option) |
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14 | ;; any later version. |
15 | ||
16 | ;; GNU Emacs is distributed in the hope that it will be useful, | |
17 | ;; but WITHOUT ANY WARRANTY; without even the implied warranty of | |
18 | ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
19 | ;; GNU General Public License for more details. | |
20 | ||
21 | ;; You should have received a copy of the GNU General Public License | |
22 | ;; along with GNU Emacs; see the file COPYING. If not, write to the | |
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23 | ;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, |
24 | ;; Boston, MA 02110-1301, USA. | |
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25 | |
26 | ;;; Commentary: | |
27 | ||
28 | ;;; Code: | |
29 | ||
30 | ;; Provide a meaningful error message if we are running on | |
31 | ;; bare (non-float) emacs. | |
32 | ||
33 | (if (fboundp 'atan) | |
34 | nil | |
35 | (error "Floating point was disabled at compile time")) | |
36 | ||
37 | ;; provide an easy hook to tell if we are running with floats or not. | |
38 | ;; define pi and e via math-lib calls. (much less prone to killer typos.) | |
39 | (defconst pi (* 4 (atan 1)) "The value of Pi (3.1415926...).") | |
8f92ec4d | 40 | |
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41 | ;; It's too inconvenient to make `e' a constant because it's used as |
42 | ;; a temporary variable all the time. | |
43 | (defvar e (exp 1) "The value of e (2.7182818...).") | |
44 | ||
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45 | (defconst degrees-to-radians (/ pi 180.0) |
46 | "Degrees to radian conversion constant.") | |
47 | (defconst radians-to-degrees (/ 180.0 pi) | |
48 | "Radian to degree conversion constant.") | |
49 | ||
50 | ;; these expand to a single multiply by a float when byte compiled | |
51 | ||
52 | (defmacro degrees-to-radians (x) | |
53 | "Convert ARG from degrees to radians." | |
54 | (list '* (/ pi 180.0) x)) | |
55 | (defmacro radians-to-degrees (x) | |
56 | "Convert ARG from radians to degrees." | |
57 | (list '* (/ 180.0 pi) x)) | |
58 | ||
59 | (provide 'lisp-float-type) | |
60 | ||
cbee283d | 61 | ;; arch-tag: e7837072-a4af-4d08-9953-8a3e755abf9d |
5e046f6d | 62 | ;;; float-sup.el ends here |