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54 lines
1.8 KiB
EmacsLisp
54 lines
1.8 KiB
EmacsLisp
;;; float-sup.el --- define some constants useful for floating point numbers.
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;; Copyright (C) 1985-1987, 2001-2018 Free Software Foundation, Inc.
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;; Maintainer: emacs-devel@gnu.org
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;; Keywords: internal
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;; Package: emacs
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;; This file is part of GNU Emacs.
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;; GNU Emacs is free software: you can redistribute it and/or modify
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;; it under the terms of the GNU General Public License as published by
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;; the Free Software Foundation, either version 3 of the License, or
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;; (at your option) any later version.
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;; GNU Emacs is distributed in the hope that it will be useful,
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;; but WITHOUT ANY WARRANTY; without even the implied warranty of
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;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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;; GNU General Public License for more details.
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;; You should have received a copy of the GNU General Public License
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;; along with GNU Emacs. If not, see <https://www.gnu.org/licenses/>.
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;;; Commentary:
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;;; Code:
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;; Provide an easy hook to tell if we are running with floats or not.
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;; Define pi and e via math-lib calls (much less prone to killer typos).
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(defconst float-pi (* 4 (atan 1)) "The value of Pi (3.1415926...).")
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(defconst pi float-pi
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"Obsolete since Emacs-23.3. Use `float-pi' instead.")
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(internal-make-var-non-special 'pi)
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(defconst float-e (exp 1) "The value of e (2.7182818...).")
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(defconst degrees-to-radians (/ float-pi 180.0)
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"Degrees to radian conversion constant.")
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(defconst radians-to-degrees (/ 180.0 float-pi)
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"Radian to degree conversion constant.")
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;; These expand to a single multiply by a float when byte compiled.
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(defmacro degrees-to-radians (x)
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"Convert X from degrees to radians."
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(list '* degrees-to-radians x))
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(defmacro radians-to-degrees (x)
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"Convert X from radians to degrees."
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(list '* radians-to-degrees x))
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(provide 'lisp-float-type)
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;;; float-sup.el ends here
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