HCoop / bpt / emacs.git / blame
| Commit | Line | Data |
|---|---|---|
| 5e046f6d JB |
1 | ;;; float-sup.el --- define some constants useful for floating point numbers. |
| 2 | ||
| 3 | ;; Copyright (C) 1985, 1986, 1987 Free Software Foundation, Inc. | |
| 4 | ||
| 5 | ;; Maintainer: FSF | |
| 6 | ;; Keywords: internal | |
| 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 2, or (at your option) | |
| 13 | ;; 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; see the file COPYING. If not, write to the | |
| 22 | ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330, | |
| 23 | ;; Boston, MA 02111-1307, USA. | |
| 24 | ||
| 25 | ;;; Commentary: | |
| 26 | ||
| 27 | ;;; Code: | |
| 28 | ||
| 29 | ;; Provide a meaningful error message if we are running on | |
| 30 | ;; bare (non-float) emacs. | |
| 31 | ||
| 32 | (if (fboundp 'atan) | |
| 33 | nil | |
| 34 | (error "Floating point was disabled at compile time")) | |
| 35 | ||
| 36 | ;; provide an easy hook to tell if we are running with floats or not. | |
| 37 | ;; define pi and e via math-lib calls. (much less prone to killer typos.) | |
| 38 | (defconst pi (* 4 (atan 1)) "The value of Pi (3.1415926...).") | |
| 39 | ;; It's too inconvenient to make `e' a constant because it's used as | |
| 40 | ;; a temporary variable all the time. | |
| 41 | (defvar e (exp 1) "The value of e (2.7182818...).") | |
| 42 | ||
| 43 | ;; Careful when editing this file ... typos here will be hard to spot. | |
| 44 | ;; (defconst pi 3.14159265358979323846264338327 | |
| 45 | ;; "The value of Pi (3.14159265358979323846264338327...)") | |
| 46 | ||
| 47 | (defconst degrees-to-radians (/ pi 180.0) | |
| 48 | "Degrees to radian conversion constant.") | |
| 49 | (defconst radians-to-degrees (/ 180.0 pi) | |
| 50 | "Radian to degree conversion constant.") | |
| 51 | ||
| 52 | ;; these expand to a single multiply by a float when byte compiled | |
| 53 | ||
| 54 | (defmacro degrees-to-radians (x) | |
| 55 | "Convert ARG from degrees to radians." | |
| 56 | (list '* (/ pi 180.0) x)) | |
| 57 | (defmacro radians-to-degrees (x) | |
| 58 | "Convert ARG from radians to degrees." | |
| 59 | (list '* (/ 180.0 pi) x)) | |
| 60 | ||
| 61 | (provide 'lisp-float-type) | |
| 62 | ||
| 63 | ;;; float-sup.el ends here |