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Update Antinews in ELisp manual

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* doc/lispref/anti.texi (Antinews): Rewrite for Emacs 27.
* doc/lispref/elisp.texi (Top): Update the top-level menu item for
Antinews.
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Eli Zaretskii 2020-01-11 13:36:07 +02:00
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@ -6,276 +6,184 @@
@c This node must have no pointers. @c This node must have no pointers.
@node Antinews @node Antinews
@appendix Emacs 25 Antinews @appendix Emacs 26 Antinews
@c Update the elisp.texi Antinews menu entry with the above version number. @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 For those users who live backwards in time, here is information about
downgrading to Emacs version 25.3. We hope you will enjoy the greater downgrading to Emacs version 26.3. We hope you will enjoy the greater
simplicity that results from the absence of many @w{Emacs simplicity that results from the absence of many @w{Emacs
@value{EMACSVER}} features. @value{EMACSVER}} features.
@section Old Lisp Features in Emacs 25
@itemize @bullet @itemize @bullet
@item @item
The concurrency features have been removed. Even in its limited Lisp objects are again implemented on the C level as integer types,
``mostly cooperative'' form, with only one Lisp thread running at any not as pointers. This might be a small step for Emacs Lisp users, but
given time, it made Emacs significantly more complex for Lisp programs it's a giant leap for the Emacs developers who work on the C level,
that need to work correctly in the presence of additional threads. 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 @item
Handling of file attributes has been simplified by discarding the The test suite was removed from the distribution tarball. We believe
accessor functions, such as @code{file-attribute-type} and that tests need seldom if ever be run, certainly not by the end
@code{file-attribute-modification-time}. Real Lisp programmers always users. Removing the tests from the tarball makes it much smaller,
access the individual attributes by their ordinal numbers, and can which is important since disk space becomes more and more at premium
recite those numbers in their sleep. as you move back in time.
@item @item
The networking code is back at its pristine simplicity, as we deleted Dynamic module support is disabled by default. This both makes Emacs
the use of asynchronous DNS resolution, connection, and TLS smaller (a worthy goal by itself), and removes the complications and
negotiation for TLS streams. You no longer need to consider the additional complexity related with installing module support files and
resulting complexity and interesting race conditions when you write letting random shared objects an opportunity to be loaded into Emacs
Lisp programs that use network communications. As a direct and mess with it.
consequence, the @code{:complete-negotiation} parameter of
@code{gnutls-boot} has become unnecessary, and was removed---just one
example of how removal of asynchronicity simplifies Emacs.
@item @item
We've removed the @file{puny.el} library, so Web sites with You now must activate any installed packages only after loading your
non-@acronym{ASCII} URLs are no longer easily accessible. But such init files. That requires an explicit call to
sites become more and more rare as you move back in time, so having a @code{package-initialize} in your init file, which is a Good Thing, as
specialized library for their support was deemed an unnecessary it makes you think seriously where and indeed whether you'd like your
maintenance burden. packages to become available to your sessions. Simplicity should
tramp convenience!
@item @item
The time conversion functions @code{current-time-string}, To reduce the amount of code in Emacs related to unimportant features,
@code{current-time-zone}, @code{decode-time}, we've removed native rotation and resizing of images. You will have
@code{format-time-string}, and @code{set-time-zone-rule} no longer to build Emacs with ImageMagick if you want to resize or rotate images
accept integer offsets as time zone rules, to make it more of a inside Emacs. We don't expect anyone to miss that.
challenge to convert foreign timestamps. Also,
@code{format-time-string} no longer converts @samp{%q} to the calendar
quarter, as that is something you can easily do for yourself.
@item @item
Field numbers like @samp{%2$} in format specifiers are no longer We've re-enabled color fonts usage by the XFT font back-end. We
available. We decided that their use makes code reading and consider the availability of these fonts more important than a random
comprehension much harder, and that having them is unjustified in the crash here and there, especially since the use of these fonts for
past where similar features in popular C libraries will also be gone. displaying Emoji will become less and less important as w travel back
in time, and will completely disappear in some past Emacs version.
@item @item
Since the built-in capability to display line numbers has been removed The function @code{network-interface-list} can now return only IPv4
(@pxref{Antinews,,, emacs, The GNU Emacs Manual}), we've also deleted addresses. We consider the complexity introduced by IPv6 to be too
the @code{line-number-display-width} function and the support for the much to be justified, and on the other hand its removal is the step in
@code{display-line-numbers-disable} property, as Lisp programs that do the right direction, given that IPv6 is expected to be completely
their own display layout decisions no longer need to cater to this removed as we move back in time.
tricky feature.
@item @item
Regular expressions have been simplified by removing support for The limit on repetitions in regular expressions was reduced to
Unicode character properties in the @code{[:blank:]} regexp class. As @ifnottex
result, this class will match only spaces and tabs. Once again, this 2**15 @minus{} 1.
is in line with diminishing importance of Unicode as you move back in @end ifnottex
time. @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 @item
For similar reasons, we removed the function @code{char-from-name}. To simplify code and reduce complexity, we removed the capability of
It should be easy enough to access the full list of Unicode characters searching programs on remote hosts in @code{executable-find}. If you
returned by @code{ucs-names} instead, for as long as Unicode support really need this feature (why would you?), you can always write your
in Emacs exists (which shouldn't be too long). own shell script and run it on the remote.
@item @item
Various functions that accept file names as arguments, such as The @code{:extend} face attribute is no longer available; all faces
@code{file-attributes}, @code{file-symlink-p}, and have their background color extended by default past end of line.
@code{make-symbolic-link} gained back the special support for file This should significantly simplify face management and remove
names quoted with @samp{/:}, and they now interpret @samp{~} in unnecessary code bloat, as well as make faces significantly simpler to
symlink targets as you'd expect: to mean your home directory. The understand and use.
confusing differences between the operation of these functions in
interactive and non-interactive invocations has been removed.
@item @item
Several functions that create or rename their files now treat their The predicates @code{display-blink-cursor-p} and
destination specially if it happens to be a directory, even when its @code{display-symbol-keys-p} were deleted. They are rarely if ever
name does not appear to be that of a directory. For example, needed, and can easily be substituted by appropriate calls to old and
@code{(rename-file "A" "B")} no longer renames @file{A} to @file{B} if proven APIs like @code{display-graphic-p}. As an additional bonus,
@file{B} happens to be a directory. This is so that dealing with writing Lisp programs that depend on this functionality will make sure
files becomes more of an adventure. the programmer understands better what exactly is the required
features of the display terminal.
@item @item
The @code{format} function now returns new strings in more cases, to Relative directories in the value of the @env{HOME} environment
place more stress on the Emacs memory manager and thereby test Emacs variable are once again interpreted relative to the
better. @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 @item
The function @file{assoc} has been simplified by removing its third File-related primitives like @code{file-attributes},
optional argument. It now always uses @code{equal} for comparison. @code{file-modes}, @code{file-newer-than-file-p}, and some others once
Likewise, @code{alist-get} always uses @code{assq}, and @code{map-get} again return @code{nil} when the underlying low-level APIs fail,
and @code{map-put} always use @code{eql} for their comparisons. 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 @item
Numeric comparisons and the functions @code{format}, Similarly, old-style backquotes no longer signal errors; they generate
@code{make-hash-table}, @code{min}, @code{max} and @code{logb} now warnings instead. You can remove error handling from programs that
occasionally round values internally to make their results less use backquotes.
predictable.
@item @item
The functions @code{ffloor}, @code{fceiling}l, @code{ftruncate} and Formatting floating-point numbers has been sped up by letting the
@code{fround} now accept integer arguments. Conversely, functions underlying implementation produce unpredictable values, instead of
like @code{decode-char} that accept floating-point integers now accept signaling errors when the number is too large to format correctly. We
arguments that are not integers. In both cases the results are believe the Emacs Lisp programmers should always know what they are
amusingly nonsensical sometimes. doing when they deal with floating-point values.
@item @item
GnuTLS cryptographic functions are no longer available in Emacs. We The function @code{read-char-from-minibuffer} was deleted. We decided
have decided that the needs for such functionality are deteriorating, that @code{read-char} should be enough for any Lisp program that needs
and their cumbersome interfaces make them hard to use. 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 @item
We have removed support for records of user-defined types, and The function @code{ngettext} was deleted. Non-English languages will
@code{cl-defstruct} no longer uses records. This removes the become less and less widespread, let alone useful, as you move back in
potential for quite a few places where existing and past code could be time, so we took this small step in that direction, and simplified
broken by records. Emacs as a nice bonus.
@item @item
You can again use @code{string-as-unibyte}, Focus-change notifications on text-mode frames are no longer
@code{string-make-multibyte}, and other similar functions, without recognized or supported. You can now safely disregard the possibility
being annoyed by messages about their deprecation. This is in of receiving such notifications on TTY frames. This is one small step
preparation for removal of multibyte text from Emacs in the distant on the long road of removing all non-character input events Emacs
past. supports on TTY frames.
@item @item
The @code{string-version-lessp} function has been removed, to Face specifications in @code{face-remapping-alist} now have to be
encourage programmers to use their own idiosyncratic methods to buffer-specific, without any differences between windows showing the
determine whether one version string precedes another. same buffers. This allowed us to remove a lot of unneeded code bloat
from Emacs, and make the face handling much simpler.
@item @item
The function @code{read-color} no longer displays color names using The @samp{%o} and @samp{%x} formats now always produce unsigned
each color as the background. We have determined that this surprises values, as you'd expect. This allows you to reveal the underlying
users and produces funny inconsistent results on color-challenged machine representation, which is different on each architecture,
terminals. something we consider a valuable feature.
@item @item
Support for 24-bit color on text terminals has been dropped, since We no longer highlight in @code{font-lock-warning-face} symbols with
it wasn't needed long ago. 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 @item
We removed the function @code{file-name-case-insensitive-p}, as The function @code{file-system-info} was dropped on Posix platforms,
testing for the OS symbol should be enough for the observable past to since you can always invoke @command{df} instead and parse its
come, and learning to use yet another API is a burden. output.
@item @item
The function @code{read-multiple-choice} is also gone, in recognition The functions that implement the @samp{base64url} encoding were
of the fact that nothing makes Emacs Lisp hackers rejoice more than removed, as they can always be emulated by suitable tweaking of the
the need to sit down and write yet another interactive normal base-64 encoding. No need to bloat Emacs and force Lisp
question-and-answer function, and make it optimal for each specific programmers learn more interfaces on this account.
case.
@item
The function @code{add-variable-watcher} and the corresponding
debugger command @code{debug-on-variable-change} have been removed.
They make debugging more complicated, while examining the value of a
variable at each stop point is easy enough to cover the same use
cases. Let simplicity rule!
@item
The function @code{mapcan} is gone; use @code{mapcar} instead, and
process the resulting list as you see fit.
@item
Low-level list functions like @code{length} and @code{member} can now
loop indefinitely when given cyclic lists, causing Emacs to freeze.
This can help these functions run a tiny bit faster in the usual case
where the input is not cyclic.
@item
The @code{write-region} function no longer propagates its
@var{lockname} argument to file name handlers.
@item
You can once again write a Lisp program that returns funny random
values from @code{file-attributes} by having another process alter the
filesystem while Emacs is accessing the file. This can give rise to
some interesting applications in the near past.
@item
The functions @code{file-attributes}, @code{file-symlink-p}, and
@code{make-symbolic-link} now quietly mutate the target of a local
symbolic link in some cases, to make it more of a challenge to deal
with arbitrary symlinks in Emacs code.
@item
The error @code{file-missing} has been removed; operations now lump
such errors into the @code{file-error} category instead.
@item
The function @code{delete-directory} now signals an error if operating
recursively and some other process deletes the directory before this
function gets to it.
@item
The @code{dutch} input method now attempts to support Turkish too,
albeit incorrectly. Also, it converts @samp{IJ} and @samp{ij} to
special characters instead of leaving them alone.
@item
Non-breaking hyphens and approximations to quotes are now displayed
just with the @code{escape-glyph} face instead of having faces of
their own. This is simpler and gives the user amusing puzzles to
solve when viewing text containing these characters.
@item
The user option @code{electric-quote-context-sensitive} and the
variable @code{electric-quote-inhibit-functions}, so that electric
quoting is simpler and more likely to do the wrong thing.
@item
The user option @code{text-quoting-style} has been removed, and is now
just a variable.
@item
We have removed the functions @code{file-name-quote},
@code{file-name-unquote}, and @code{file-name-quoted-p}. Writing code
that checks whether a file name is already quoted is easy, and doubly
quoting a file name should not produce any problems for well-written
Lisp code.
@item
Frame parameters like @code{z-group}, @code{min-width},
@code{parent-frame}, @code{delete-before}, etc. have been removed.
Emacs should not replace your window-manager, certainly not as
window-managers become less and less capable.
@item
We decided that the format of mode line and header line should be
customizable only based on buffers; the @code{mode-line-format} and
@code{header-line-format} window parameters have been removed.
@item
Emacs now normally builds a limited @command{movemail} substitute that
retrieves POP3 email only via insecure channels, and the
configure-time option @option{--with-mailutils} has been removed.
This simplifies Emacs setup when security is not important.
@item
The configure-time option @option{--enable-gcc-warnings=warn-only}
has been removed, so that build-time warnings are always fatal now.
@item
The configure-time option @option{--disable-build-details} has been
removed. This way, Emacs builds are unique and irreproducible.
@item
The variable @code{emacs-version} now includes the build number
instead of storing it separately in @code{emacs-build-number}.
@item
Emacs has been ported to IRIX.
@item
Several options and variables have been removed to simplify Emacs and
potentially make it less reliable. These include the
@option{--module-assertions} option, the
@code{attempt-stack-overflow-recovery} variable, and the
@code{attempt-orderly-shutdown-on-fatal-signal} variable.
@item @item
As part of the ongoing quest for simplicity, many other functions and As part of the ongoing quest for simplicity, many other functions and

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@ -233,7 +233,7 @@ To view this manual in other formats, click
Appendices Appendices
* Antinews:: Info for users downgrading to Emacs 25. * Antinews:: Info for users downgrading to Emacs 26.
* GNU Free Documentation License:: The license for this documentation. * GNU Free Documentation License:: The license for this documentation.
* GPL:: Conditions for copying and changing GNU Emacs. * GPL:: Conditions for copying and changing GNU Emacs.
* Tips:: Advice and coding conventions for Emacs Lisp. * Tips:: Advice and coding conventions for Emacs Lisp.