Update Antinews in ELisp manual
* doc/lispref/anti.texi (Antinews): Update for Emacs 25.1. * doc/lispref/elisp.texi (Top): Update the main menu entry for Antinews.
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Eli Zaretskii
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2 changed files with 72 additions and 94 deletions
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@c This node must have no pointers.
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@node Antinews
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@appendix Emacs 23 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 23.4. We hope you will enjoy the greater
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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 23
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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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Support for lexical scoping has been removed; all variables are
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dynamically scoped. The @code{lexical-binding} variable has been
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removed, and so has the @var{lexical} argument to @code{eval}. The
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@code{defvar} and @code{defconst} forms no longer mark variables as
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dynamic, since all variables are dynamic.
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Having only dynamic binding follows the spirit of Emacs extensibility,
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for it allows any Emacs code to access any defined variable with a
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minimum of fuss. But @xref{Dynamic Binding Tips}, for tips to avoid
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making your programs hard to understand.
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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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Calling a minor mode function from Lisp with a @code{nil} or omitted argument
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does not enable the minor mode unconditionally; instead, it toggles
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the minor mode---which is the straightforward thing to do, since that
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is the behavior when invoked interactively. One downside is that it
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is more troublesome to enable minor modes from hooks; you have to do
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something like
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@example
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(add-hook 'foo-hook (lambda () (bar-mode 1)))
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@end example
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@noindent
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or define @code{turn-on-bar-mode} and call that from the hook.
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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{prog-mode} dummy major mode has been removed. Instead of
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using it as a crutch to meet programming mode conventions, you should
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explicitly ensure that your mode follows those conventions.
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@xref{Major Mode Conventions}.
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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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Emacs no longer supports bidirectional display and editing. Since
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there is no need to worry about the insertion of right-to-left text
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messing up how lines and paragraphs are displayed, the function
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@code{bidi-string-mark-left-to-right} has been removed; so have many
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other functions and variables related to bidirectional display.
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Unicode directionality characters like @code{U+200E} LEFT-TO-RIGHT
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MARK have no special effect on display.
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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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Emacs windows now have most of their internal state hidden from Lisp.
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Internal windows are no longer visible to Lisp; functions such as
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@code{window-parent}, window parameters related to window arrangement,
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and window-local buffer lists have all been removed. Functions for
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resizing windows can delete windows if they become too small.
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The action-function feature for controlling buffer display has
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been removed, including @code{display-buffer-overriding-action} and
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related variables, as well as the @var{action} argument to
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@code{display-buffer} and other functions. The way to
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programmatically control how Emacs chooses a window to display a
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buffer is to bind the right combination of @code{pop-up-frames} and
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other variables.
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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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The standard completion interface has been simplified, eliminating the
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@code{completion-extra-properties} variable, the @code{metadata}
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action flag for completion functions, and the concept of
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completion categories. Lisp programmers may now find the choice
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of methods for tuning completion less bewildering, but if a package
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finds the streamlined interface insufficient for its needs, it must
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implement its own specialized completion feature.
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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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@code{copy-directory} now behaves the same whether or not the
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destination is an existing directory: if the destination exists, the
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@emph{contents} of the first directory are copied into it (with
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subdirectories handled recursively), rather than copying the first
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directory into a subdirectory.
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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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The @var{trash} arguments for @code{delete-file} and
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@code{delete-directory} have been removed. The variable
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@code{delete-by-moving-to-trash} must now be used with care; whenever
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it is non-@code{nil}, all calls to @code{delete-file} or
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@code{delete-directory} use the trash.
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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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Because Emacs no longer supports SELinux file contexts, the
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@var{preserve-selinux-context} argument to @code{copy-file} has been
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removed. The return value of @code{backup-buffer} no longer has an
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entry for the SELinux file context.
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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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For mouse click input events in the text area, the Y pixel coordinate
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in the @var{position} list (@pxref{Click Events}) now counts from the
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top of the header line, if there is one, rather than the top of the
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text area.
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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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Bindings in menu keymaps (@pxref{Format of Keymaps}) now sometimes get
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an additional @var{cache} entry in their definitions, like this:
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@example
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(@var{type} @var{item-name} @var{cache} . @var{binding})
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@end example
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@noindent
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The @var{cache} entry is used internally by Emacs to record equivalent
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keyboard key sequences for invoking the same command; Lisp programs
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should never use it.
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@c Not really NEWS-worthy then...
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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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The @code{gnutls} library has been removed, and the function
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@code{open-network-stream} correspondingly simplified.
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Lisp programs that want an encrypted network connection must now call
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external utilities such as @command{starttls} or @command{gnutls-cli}.
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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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Tool bars can no longer display separators, which frees up several
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pixels of space on each graphical frame.
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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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@ -228,7 +228,7 @@ To view this manual in other formats, click
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Appendices
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* Antinews:: Info for users downgrading to Emacs 23.
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* Antinews:: Info for users downgrading to Emacs 24.
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* GNU Free Documentation License:: The license for this documentation.
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* GPL:: Conditions for copying and changing GNU Emacs.
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* Tips:: Advice and coding conventions for Emacs Lisp.
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