[bpt/emacs.git] / lisp / float-sup.el

;;; float-sup.el --- detect absence of floating-point support in Emacs runtime

;; Copyright (C) 1985, 1986, 1987 Free Software Foundation, Inc.

;; Maintainer: FSF

;; 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 2, 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; see the file COPYING.  If not, write to
;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.

;;; Code:

;; Provide a meaningful error message if we are running on
;; bare (non-float) emacs.
;; Can't test for 'floatp since that may be defined by float-imitation
;; packages like float.el in this very directory.

(if (fboundp 'atan)
    nil
  (error "Floating point was disabled at compile time"))

;; provide an easy hook to tell if we are running with floats or not.
;; define pi and e via math-lib calls. (much less prone to killer typos.)
(defconst pi (* 4 (atan 1)) "The value of Pi (3.1415926...)")
(defconst e (exp 1) "The value of e (2.7182818...)")

;; Careful when editing this file ... typos here will be hard to spot.
;; (defconst pi       3.14159265358979323846264338327
;;  "The value of Pi (3.14159265358979323846264338327...)")

(defconst degrees-to-radians (/ pi 180.0)
  "Degrees to radian conversion constant")
(defconst radians-to-degrees (/ 180.0 pi)
  "Radian to degree conversion constant")

;; these expand to a single multiply by a float when byte compiled

(defmacro degrees-to-radians (x)
  "Convert ARG from degrees to radians."
  (list '* (/ pi 180.0) x))
(defmacro radians-to-degrees (x)
  "Convert ARG from radians to degrees."
  (list '* (/ 180.0 pi) x))

(provide 'lisp-float-type)

;;; float-sup.el ends here
Commit	Line	Data
c0274f38 ER	1	;;; float-sup.el --- detect absence of floating-point support in Emacs runtime
c0274f38 ER	2
a2535589 JA	3	;; Copyright (C) 1985, 1986, 1987 Free Software Foundation, Inc.
a2535589 JA	4
9750e079 ER	5	;; Maintainer: FSF
9750e079 ER	6
a2535589 JA	7	;; This file is part of GNU Emacs.
	8
	9	;; GNU Emacs is free software; you can redistribute it and/or modify
	10	;; it under the terms of the GNU General Public License as published by
e5167999	11	;; the Free Software Foundation; either version 2, or (at your option)
a2535589 JA	12	;; any later version.
	13
	14	;; GNU Emacs is distributed in the hope that it will be useful,
	15	;; but WITHOUT ANY WARRANTY; without even the implied warranty of
	16	;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	17	;; GNU General Public License for more details.
	18
	19	;; You should have received a copy of the GNU General Public License
	20	;; along with GNU Emacs; see the file COPYING. If not, write to
	21	;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
	22
e5167999 ER	23	;;; Code:
e5167999 ER	24
a2535589 JA	25	;; Provide a meaningful error message if we are running on
	26	;; bare (non-float) emacs.
	27	;; Can't test for 'floatp since that may be defined by float-imitation
	28	;; packages like float.el in this very directory.
	29
	30	(if (fboundp 'atan)
	31	nil
	32	(error "Floating point was disabled at compile time"))
	33
	34	;; provide an easy hook to tell if we are running with floats or not.
a2535589 JA	35	;; define pi and e via math-lib calls. (much less prone to killer typos.)
	36	(defconst pi (* 4 (atan 1)) "The value of Pi (3.1415926...)")
	37	(defconst e (exp 1) "The value of e (2.7182818...)")
	38
	39	;; Careful when editing this file ... typos here will be hard to spot.
	40	;; (defconst pi 3.14159265358979323846264338327
	41	;; "The value of Pi (3.14159265358979323846264338327...)")
	42
	43	(defconst degrees-to-radians (/ pi 180.0)
	44	"Degrees to radian conversion constant")
	45	(defconst radians-to-degrees (/ 180.0 pi)
	46	"Radian to degree conversion constant")
	47
3bfd7edb	48	;; these expand to a single multiply by a float when byte compiled
a2535589 JA	49
	50	(defmacro degrees-to-radians (x)
	51	"Convert ARG from degrees to radians."
	52	(list '* (/ pi 180.0) x))
	53	(defmacro radians-to-degrees (x)
	54	"Convert ARG from radians to degrees."
	55	(list '* (/ 180.0 pi) x))
49116ac0 JB	56
	57	(provide 'lisp-float-type)
	58
c0274f38	59	;;; float-sup.el ends here