*** empty log message ***
[emacs.git] / lisp / float-sup.el
blob29b918a3bc352c830b15899fbd311b6abfe48224
1 ;;; float-sup.el --- detect absence of floating-point support in Emacs runtime
3 ;; Copyright (C) 1985, 1986, 1987 Free Software Foundation, Inc.
5 ;; Maintainer: FSF
6 ;; Keywords: internal
8 ;; This file is part of GNU Emacs.
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.
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.
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.
25 ;;; Commentary:
27 ;;; Code:
29 ;; Provide a meaningful error message if we are running on
30 ;; bare (non-float) emacs.
32 (if (fboundp 'atan)
33 nil
34 (error "Floating point was disabled at compile time"))
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...).")
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...)")
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.")
52 ;; these expand to a single multiply by a float when byte compiled
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))
61 (provide 'lisp-float-type)
63 ;;; float-sup.el ends here