lisp/float-sup.el

   1 ;; Basic editing commands for Emacs
   2 ;; Copyright (C) 1985, 1986, 1987 Free Software Foundation, Inc.
   3
   4 ;; This file is part of GNU Emacs.
   5
   6 ;; GNU Emacs is free software; you can redistribute it and/or modify
   7 ;; it under the terms of the GNU General Public License as published by
   8 ;; the Free Software Foundation; either version 1, or (at your option)
   9 ;; any later version.
  10
  11 ;; GNU Emacs is distributed in the hope that it will be useful,
  12 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 ;; GNU General Public License for more details.
  15
  16 ;; You should have received a copy of the GNU General Public License
  17 ;; along with GNU Emacs; see the file COPYING.  If not, write to
  18 ;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
  19
  20 ;; Provide a meaningful error message if we are running on
  21 ;; bare (non-float) emacs.
  22 ;; Can't test for 'floatp since that may be defined by float-imitation
  23 ;; packages like float.el in this very directory.
  24
  25 (if (fboundp 'atan)
  26     nil
  27   (error "Floating point was disabled at compile time"))
  28
  29 ;; provide an easy hook to tell if we are running with floats or not.
  30 ;; define pi and e via math-lib calls. (much less prone to killer typos.)
  31 (defconst pi (* 4 (atan 1)) "The value of Pi (3.1415926...)")
  32 (defconst e (exp 1) "The value of e (2.7182818...)")
  33
  34 ;; Careful when editing this file ... typos here will be hard to spot.
  35 ;; (defconst pi       3.14159265358979323846264338327
  36 ;;  "The value of Pi (3.14159265358979323846264338327...)")
  37
  38 (defconst degrees-to-radians (/ pi 180.0)
  39   "Degrees to radian conversion constant")
  40 (defconst radians-to-degrees (/ 180.0 pi)
  41   "Radian to degree conversion constant")
  42
  43 ;; these expand to a single multiply by a float when byte compiled
  44
  45 (defmacro degrees-to-radians (x)
  46   "Convert ARG from degrees to radians."
  47   (list '* (/ pi 180.0) x))
  48 (defmacro radians-to-degrees (x)
  49   "Convert ARG from radians to degrees."
  50   (list '* (/ 180.0 pi) x))
  51
  52 (provide 'lisp-float-type)
  53