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;;; float-sup.el --- define some constants useful for floating point numbers.
;; Copyright (C) 1985-1987, 2001-2012 Free Software Foundation, Inc.
;; Maintainer: FSF
;; Keywords: internal
;; Package: emacs
;; 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 3 of the License, 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. If not, see <http://www.gnu.org/licenses/>.
;;; Commentary:
;;; Code:
;; 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 float-pi (* 4 (atan 1)) "The value of Pi (3.1415926...).")
(progn
;; Simulate a defconst that doesn't declare the variable dynamically bound.
(setq-default pi float-pi)
(put 'pi 'variable-documentation
"Obsolete since Emacs-23.3. Use `float-pi' instead.")
(put 'pi 'risky-local-variable t)
(push 'pi current-load-list))
(defconst float-e (exp 1) "The value of e (2.7182818...).")
(defconst degrees-to-radians (/ float-pi 180.0)
"Degrees to radian conversion constant.")
(defconst radians-to-degrees (/ 180.0 float-pi)
"Radian to degree conversion constant.")
;; These expand to a single multiply by a float when byte compiled.
(defmacro degrees-to-radians (x)
"Convert X from degrees to radians."
(list '* degrees-to-radians x))
(defmacro radians-to-degrees (x)
"Convert X from radians to degrees."
(list '* radians-to-degrees x))
(provide 'lisp-float-type)
;;; float-sup.el ends here
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