Commit 0ad74106 authored by Eli Zaretskii's avatar Eli Zaretskii

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.
parent ea0f750e
......@@ -6,132 +6,110 @@
@c This node must have no pointers.
@node Antinews
@appendix Emacs 23 Antinews
@appendix Emacs 24 Antinews
@c Update the elisp.texi Antinews menu entry with the above version number.
For those users who live backwards in time, here is information about
downgrading to Emacs version 23.4. We hope you will enjoy the greater
downgrading to Emacs version 24.5. We hope you will enjoy the greater
simplicity that results from the absence of many Emacs @value{EMACSVER}
features.
@section Old Lisp Features in Emacs 23
@section Old Lisp Features in Emacs 24
@itemize @bullet
@item
Support for lexical scoping has been removed; all variables are
dynamically scoped. The @code{lexical-binding} variable has been
removed, and so has the @var{lexical} argument to @code{eval}. The
@code{defvar} and @code{defconst} forms no longer mark variables as
dynamic, since all variables are dynamic.
Having only dynamic binding follows the spirit of Emacs extensibility,
for it allows any Emacs code to access any defined variable with a
minimum of fuss. But @xref{Dynamic Binding Tips}, for tips to avoid
making your programs hard to understand.
The requirement that @code{setq} and @code{setf} must be called with
an even number of arguments has been removed. You can now call them
with an odd number of arguments, and Emacs will helpfully supply a
@code{nil} for the missing one. Simplicity rules!
@item
Calling a minor mode function from Lisp with a @code{nil} or omitted argument
does not enable the minor mode unconditionally; instead, it toggles
the minor mode---which is the straightforward thing to do, since that
is the behavior when invoked interactively. One downside is that it
is more troublesome to enable minor modes from hooks; you have to do
something like
@example
(add-hook 'foo-hook (lambda () (bar-mode 1)))
@end example
@noindent
or define @code{turn-on-bar-mode} and call that from the hook.
@kbd{M-x shell} and @kbd{M-x compile} set the @env{EMACS} environment
variable, as they should, to indicate that the subprocess is run by
Emacs. This is so packages that took years to learn how to work
around that setting could continue using their code to that effect.
@item
The @code{prog-mode} dummy major mode has been removed. Instead of
using it as a crutch to meet programming mode conventions, you should
explicitly ensure that your mode follows those conventions.
@xref{Major Mode Conventions}.
The @code{save-excursion} form saves and restores the mark, as
expected. No more need for the new @code{save-mark-and-excursion},
which has been deleted.
@item
Emacs no longer supports bidirectional display and editing. Since
there is no need to worry about the insertion of right-to-left text
messing up how lines and paragraphs are displayed, the function
@code{bidi-string-mark-left-to-right} has been removed; so have many
other functions and variables related to bidirectional display.
Unicode directionality characters like @code{U+200E} LEFT-TO-RIGHT
MARK have no special effect on display.
We have removed the @code{text-quoting-style} variable and the
associated functionality that translates quote characters in messages
displayed to the user and in help buffers. Emacs now shows exactly
the same quote characters as you wrote in your code! Likewise,
@code{substitute-command-keys} leaves the quote characters alone. As
you move back in time, Unicode support becomes less and less
important, so no need to display those fancy new quotes the Unicode
Standard invented.
@item
Emacs windows now have most of their internal state hidden from Lisp.
Internal windows are no longer visible to Lisp; functions such as
@code{window-parent}, window parameters related to window arrangement,
and window-local buffer lists have all been removed. Functions for
resizing windows can delete windows if they become too small.
The action-function feature for controlling buffer display has
been removed, including @code{display-buffer-overriding-action} and
related variables, as well as the @var{action} argument to
@code{display-buffer} and other functions. The way to
programmatically control how Emacs chooses a window to display a
buffer is to bind the right combination of @code{pop-up-frames} and
other variables.
Regular expressions have been simplified by removing support for
Unicode character properties in regexp classes. As result,
@code{[:alpha:]} and @code{[:alnum:]} will match any character with a
word syntax, and @code{[:graph:]} and @code{[:print:]} will match any
multibyte character, including surrogates and unassigned codepoints.
Once again, this is in line with diminishing importance of Unicode as
you move back in time.
@item
The standard completion interface has been simplified, eliminating the
@code{completion-extra-properties} variable, the @code{metadata}
action flag for completion functions, and the concept of
completion categories. Lisp programmers may now find the choice
of methods for tuning completion less bewildering, but if a package
finds the streamlined interface insufficient for its needs, it must
implement its own specialized completion feature.
Evaluating @samp{(/ @var{n})} will now yield @var{n}. We have
realized that interpreting that as in Common Lisp was a bad mistake
that needed to be corrected.
@item
@code{copy-directory} now behaves the same whether or not the
destination is an existing directory: if the destination exists, the
@emph{contents} of the first directory are copied into it (with
subdirectories handled recursively), rather than copying the first
directory into a subdirectory.
The @code{pcase} form was significantly simplified by removing the
UPatterns @code{quote} and @code{app}. To further simplify this
facility, we've removed @code{pcase-defmacro}, since we found no need
for letting Lisp programs define new UPatterns.
@item
The @var{trash} arguments for @code{delete-file} and
@code{delete-directory} have been removed. The variable
@code{delete-by-moving-to-trash} must now be used with care; whenever
it is non-@code{nil}, all calls to @code{delete-file} or
@code{delete-directory} use the trash.
We've removed the text properties @code{cursor-intangible} and
@code{cursor-sensor-functions}, replacing them by the much simpler
@code{intangible}, @code{point-entered}, and @code{point-left}
properties. The latter are implemented on a much lower level, and
therefore are better integrated with user expectations. For similar
reasons, @code{cursor-intangible-mode} and @code{cursor-sensor-mode}
were removed; use the hook variable @code{inhibit-point-motion-hooks}
which is no longer obsolete.
@item
Because Emacs no longer supports SELinux file contexts, the
@var{preserve-selinux-context} argument to @code{copy-file} has been
removed. The return value of @code{backup-buffer} no longer has an
entry for the SELinux file context.
Process creation and management functions were significantly improved
and simplified by removing @code{make-process} and the @code{pipe}
connection type. Redirecting @code{stderr} of a subprocess should be
done with shell facilities, not by Emacs.
@item
For mouse click input events in the text area, the Y pixel coordinate
in the @var{position} list (@pxref{Click Events}) now counts from the
top of the header line, if there is one, rather than the top of the
text area.
We decided that shutting up informative messages is bad for user
interaction, so we've removed the @code{inhibit-message} variable
which could be used to that effect.
@item
Bindings in menu keymaps (@pxref{Format of Keymaps}) now sometimes get
an additional @var{cache} entry in their definitions, like this:
Support for generators and for finalizers has been removed, as we
found no real need for these facilities.
@example
(@var{type} @var{item-name} @var{cache} . @var{binding})
@end example
@noindent
The @var{cache} entry is used internally by Emacs to record equivalent
keyboard key sequences for invoking the same command; Lisp programs
should never use it.
@c Not really NEWS-worthy then...
@item
Due to excessive complexity and the diminishing need for Unicode
support, the functions @code{string-collate-lessp} and
@code{string-collate-equalp} were removed. Their locale-independent
counterparts @code{string-lessp} and @code{string-equal} are so much
more simple and yield predictable results that we don't see any
situation where the locale-dependent collation could be useful in
Emacs. As result, the @file{ls-lisp.el} package sorts files in a
locale-independent manner.
@item
The @code{gnutls} library has been removed, and the function
@code{open-network-stream} correspondingly simplified.
Lisp programs that want an encrypted network connection must now call
external utilities such as @command{starttls} or @command{gnutls-cli}.
In preparation for removal in some past version of Emacs of the
bidirectional editing support, we started by deleting two functions
@code{bidi-find-overridden-directionality} and
@code{buffer-substring-with-bidi-context}.
@item
Tool bars can no longer display separators, which frees up several
pixels of space on each graphical frame.
Time conversion functions, such as @code{current-time-string}, no
longer accept an optional @var{zone} argument. If you need to change
the current time zone (why?), do that explicitly with
@code{set-time-zone-rule}.
@item
As part of the ongoing quest for simplicity, many other functions and
......
......@@ -228,7 +228,7 @@ To view this manual in other formats, click
Appendices
* Antinews:: Info for users downgrading to Emacs 23.
* Antinews:: Info for users downgrading to Emacs 24.
* GNU Free Documentation License:: The license for this documentation.
* GPL:: Conditions for copying and changing GNU Emacs.
* Tips:: Advice and coding conventions for Emacs Lisp.
......
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