emacs/doc/lispref/anti.texi

@c -*-texinfo-*-
@c This is part of the GNU Emacs Lisp Reference Manual.
@c Copyright (C) 1999, 2002--2021 Free Software Foundation, Inc.
@c See the file elisp.texi for copying conditions.

@c This node must have no pointers.

@node Antinews
@appendix Emacs 26 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 26.3.  We hope you will enjoy the greater
simplicity that results from the absence of many @w{Emacs
@value{EMACSVER}} features.

@itemize @bullet
@item
Lisp objects are again implemented on the C level as integer types,
not as pointers.  This might be a small step for Emacs Lisp users, but
it's a giant leap for the Emacs developers who work on the C level,
since it is now again easy to print Lisp object in the debugger in the
decimal format, which is so much easier for debugging.  It also makes
calling Emacs functions from the debugger easier, and allows us to
freely mix integers and Lisp objects in the C code.

@item
The test suite was removed from the distribution tarball.  We believe
that tests need seldom if ever be run, certainly not by the end
users.  Removing the tests from the tarball makes it much smaller,
which is important since disk space becomes more and more at premium
as you move back in time.

@item
Dynamic module support is disabled by default.  This both makes Emacs
smaller (a worthy goal by itself), and removes the complications and
additional complexity related with installing module support files and
letting random shared objects an opportunity to be loaded into Emacs
and mess with it.

@item
You now must activate any installed packages only after loading your
init files.  That requires an explicit call to
@code{package-initialize} in your init file, which is a Good Thing, as
it makes you think seriously where and indeed whether you'd like your
packages to become available to your sessions.  Simplicity should
tramp convenience!

@item
To reduce the amount of code in Emacs related to unimportant features,
we've removed native rotation and resizing of images.  You will have
to build Emacs with ImageMagick if you want to resize or rotate images
inside Emacs.  We don't expect anyone to miss that.

@item
We've re-enabled color fonts usage by the XFT font back-end.  We
consider the availability of these fonts more important than a random
crash here and there, especially since the use of these fonts for
displaying Emoji will become less and less important as we travel back
in time, and will completely disappear in some past Emacs version.

@item
The function @code{network-interface-list} can now return only IPv4
addresses.  We consider the complexity introduced by IPv6 to be too
much to be justified, and on the other hand its removal is the step in
the right direction, given that IPv6 is expected to be completely
removed as we move back in time.

@item
The limit on repetitions in regular expressions was reduced to
@ifnottex
2**15 @minus{} 1.
@end ifnottex
@tex
@math{2^{15}-1}.
@end tex
We envision that regular expressions will become more and more simple
as we move towards the distant past.

@item
To simplify code and reduce complexity, we removed the capability of
searching programs on remote hosts in @code{executable-find}.  If you
really need this feature (why would you?), you can always write your
own shell script and run it on the remote.

@item
The @code{:extend} face attribute is no longer available; all faces
have their background color extended by default past end of line.
This should significantly simplify face management and remove
unnecessary code bloat, as well as make faces significantly simpler to
understand and use.

@item
The predicates @code{display-blink-cursor-p} and
@code{display-symbol-keys-p} were deleted.  They are rarely if ever
needed, and can easily be substituted by appropriate calls to old and
proven APIs like @code{display-graphic-p}.  As an additional bonus,
writing Lisp programs that depend on this functionality will make sure
the programmer understands better what exactly is the required
features of the display terminal.

@item
Relative directories in the value of the @env{HOME} environment
variable are once again interpreted relative to the
@code{default-directory} of the current buffer.  This is much simpler,
and also allows @env{HOME} to resolve to a different place in
different buffers, which allows some interesting applications.

For the same reasons, @code{file-name-absolute-p} now again considers
@file{~foo} an absolute file name, even if there's no known user
@samp{foo}.  This means a Lisp program which uses such file names will
always work the same on any system, regardless of its known users.

@item
File-related primitives like @code{file-attributes},
@code{file-modes}, @code{file-newer-than-file-p}, and some others once
again return @code{nil} when the underlying low-level APIs fail,
instead of signaling an error.  We decided that functions which signal
errors require more complex code from Lisp programs which use them,
and found this complexity unjustified when returning @code{nil} will
do.

@item
Similarly, old-style backquotes no longer signal errors; they generate
warnings instead.  You can remove error handling from programs that
use backquotes.

@item
Formatting floating-point numbers has been sped up by letting the
underlying implementation produce unpredictable values, instead of
signaling errors when the number is too large to format correctly.  We
believe the Emacs Lisp programmers should always know what they are
doing when they deal with floating-point values.

@item
The function @code{read-char-from-minibuffer} was deleted.  We decided
that @code{read-char} should be enough for any Lisp program that needs
to ask the user for a single-character input, in recognition of the
fact that nothing makes Emacs Lisp hackers rejoice more than the need
to sit down and write yet another interactive question-and-answer
function, and make it optimal for each specific case.  Consequently,
no history is provided for such responses (why would someone want
history of single-key strokes, anyway?).

@item
The function @code{ngettext} was deleted.  Non-English languages will
become less and less widespread, let alone useful, as you move back in
time, so we took this small step in that direction, and simplified
Emacs as a nice bonus.

@item
Focus-change notifications on text-mode frames are no longer
recognized or supported.  You can now safely disregard the possibility
of receiving such notifications on TTY frames.  This is one small step
on the long road of removing all non-character input events Emacs
supports on TTY frames.

@item
Face specifications in @code{face-remapping-alist} now have to be
buffer-specific, without any differences between windows showing the
same buffers.  This allowed us to remove a lot of unneeded code bloat
from Emacs, and make the face handling much simpler.

@item
The @samp{%o} and @samp{%x} formats now always produce unsigned
values, as you'd expect.  This allows you to reveal the underlying
machine representation, which is different on each architecture,
something we consider a valuable feature.

@item
We no longer highlight in @code{font-lock-warning-face} symbols with
confusable quote characters, such as U+2018.  Detecting them
needed  non-trivial amount of code, and we firmly believe that Lisp
programmers always know what they are doing, and don't need to be
annoyed with typefaces that stand out and distract.

@item
The function @code{file-system-info} was dropped on Posix platforms,
since you can always invoke @command{df} instead and parse its
output.

@item
The functions that implement the @samp{base64url} encoding were
removed, as they can always be emulated by suitable tweaking of the
normal base-64 encoding.  No need to bloat Emacs and force Lisp
programmers learn more interfaces on this account.

@item
As part of the ongoing quest for simplicity, many other functions and
variables have been eliminated.
@end itemize