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118 lines
4.7 KiB
Plaintext
118 lines
4.7 KiB
Plaintext
@c -*-texinfo-*-
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@c This is part of the GNU Emacs Lisp Reference Manual.
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@c Copyright (C) 1999, 2002-2017 Free Software Foundation, Inc.
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@c See the file elisp.texi for copying conditions.
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@c This node must have no pointers.
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@node Antinews
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@appendix Emacs 24 Antinews
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@c Update the elisp.texi Antinews menu entry with the above version number.
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For those users who live backwards in time, here is information about
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downgrading to Emacs version 24.5. We hope you will enjoy the greater
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simplicity that results from the absence of many Emacs @value{EMACSVER}
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features.
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@section Old Lisp Features in Emacs 24
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@itemize @bullet
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@item
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The requirement that @code{setq} and @code{setf} must be called with
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an even number of arguments has been removed. You can now call them
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with an odd number of arguments, and Emacs will helpfully supply a
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@code{nil} for the missing one. Simplicity rules!
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@item
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@kbd{M-x shell} and @kbd{M-x compile} set the @env{EMACS} environment
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variable, as they should, to indicate that the subprocess is run by
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Emacs. This is so packages that took years to learn how to work
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around that setting could continue using their code to that effect.
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@item
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The @code{save-excursion} form saves and restores the mark, as
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expected. No more need for the new @code{save-mark-and-excursion},
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which has been deleted.
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@item
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We have removed the @code{text-quoting-style} variable and the
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associated functionality that translates quote characters in messages
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displayed to the user and in help buffers. Emacs now shows exactly
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the same quote characters as you wrote in your code! Likewise,
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@code{substitute-command-keys} leaves the quote characters alone. As
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you move back in time, Unicode support becomes less and less
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important, so no need to display those fancy new quotes the Unicode
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Standard invented.
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@item
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Regular expressions have been simplified by removing support for
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Unicode character properties in regexp classes. As result,
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@code{[:alpha:]} and @code{[:alnum:]} will match any character with a
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word syntax, and @code{[:graph:]} and @code{[:print:]} will match any
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multibyte character, including surrogates and unassigned codepoints.
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Once again, this is in line with diminishing importance of Unicode as
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you move back in time.
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@item
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Evaluating @samp{(/ @var{n})} will now yield @var{n}. We have
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realized that interpreting that as in Common Lisp was a bad mistake
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that needed to be corrected.
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@item
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The @code{pcase} form was significantly simplified by removing the
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UPatterns @code{quote} and @code{app}. To further simplify this
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facility, we've removed @code{pcase-defmacro}, since we found no need
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for letting Lisp programs define new UPatterns.
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@item
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We've removed the text properties @code{cursor-intangible} and
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@code{cursor-sensor-functions}, replacing them by the much simpler
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@code{intangible}, @code{point-entered}, and @code{point-left}
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properties. The latter are implemented on a much lower level, and
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therefore are better integrated with user expectations. For similar
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reasons, @code{cursor-intangible-mode} and @code{cursor-sensor-mode}
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were removed; use the hook variable @code{inhibit-point-motion-hooks}
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which is no longer obsolete.
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@item
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Process creation and management functions were significantly improved
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and simplified by removing @code{make-process} and the @code{pipe}
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connection type. Redirecting @code{stderr} of a subprocess should be
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done with shell facilities, not by Emacs.
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@item
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We decided that shutting up informative messages is bad for user
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interaction, so we've removed the @code{inhibit-message} variable
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which could be used to that effect.
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@item
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Support for generators and for finalizers has been removed, as we
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found no real need for these facilities.
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@item
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Due to excessive complexity and the diminishing need for Unicode
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support, the functions @code{string-collate-lessp} and
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@code{string-collate-equalp} were removed. Their locale-independent
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counterparts @code{string-lessp} and @code{string-equal} are so much
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more simple and yield predictable results that we don't see any
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situation where the locale-dependent collation could be useful in
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Emacs. As result, the @file{ls-lisp.el} package sorts files in a
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locale-independent manner.
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@item
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In preparation for removal in some past version of Emacs of the
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bidirectional editing support, we started by deleting two functions
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@code{bidi-find-overridden-directionality} and
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@code{buffer-substring-with-bidi-context}.
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@item
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Time conversion functions, such as @code{current-time-string}, no
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longer accept an optional @var{zone} argument. If you need to change
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the current time zone (why?), do that explicitly with
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@code{set-time-zone-rule}.
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@item
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As part of the ongoing quest for simplicity, many other functions and
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variables have been eliminated.
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@end itemize
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