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[Emacs-diffs] Changes to emacs/lispref/numbers.texi
From: |
Richard M . Stallman |
Subject: |
[Emacs-diffs] Changes to emacs/lispref/numbers.texi |
Date: |
Fri, 24 Jun 2005 22:29:47 -0400 |
Index: emacs/lispref/numbers.texi
diff -c emacs/lispref/numbers.texi:1.34 emacs/lispref/numbers.texi:1.35
*** emacs/lispref/numbers.texi:1.34 Mon Feb 14 10:19:36 2005
--- emacs/lispref/numbers.texi Sat Jun 25 02:29:46 2005
***************
*** 183,203 ****
NaN. For practical purposes, there's no significant difference between
different NaN values in Emacs Lisp, and there's no rule for precisely
which NaN value should be used in a particular case, so Emacs Lisp
! doesn't try to distinguish them. Here are the read syntaxes for
! these special floating point values:
@table @asis
@item positive infinity
@samp{1.0e+INF}
@item negative infinity
@samp{-1.0e+INF}
! @item Not-a-number
! @samp{0.0e+NaN}.
@end table
! In addition, the value @code{-0.0} is distinguishable from ordinary
! zero in @acronym{IEEE} floating point (although @code{equal} and
! @code{=} consider them equal values).
You can use @code{logb} to extract the binary exponent of a floating
point number (or estimate the logarithm of an integer):
--- 183,208 ----
NaN. For practical purposes, there's no significant difference between
different NaN values in Emacs Lisp, and there's no rule for precisely
which NaN value should be used in a particular case, so Emacs Lisp
! doesn't try to distinguish them (but it does report the sign, if you
! print it). Here are the read syntaxes for these special floating
! point values:
@table @asis
@item positive infinity
@samp{1.0e+INF}
@item negative infinity
@samp{-1.0e+INF}
! @item Not-a-number
! @samp{0.0e+NaN} or @samp{-0.0e+NaN}.
@end table
! To test whether a floating point value is a NaN, compare it with
! itself using @code{=}. That returns @code{nil} for a NaN, and
! @code{t} for any other floating point value.
!
! The value @code{-0.0} is distinguishable from ordinary zero in
! @acronym{IEEE} floating point, but Emacs Lisp @code{equal} and
! @code{=} consider them equal values.
You can use @code{logb} to extract the binary exponent of a floating
point number (or estimate the logarithm of an integer):
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Richard M . Stallman <=