diff options
Diffstat (limited to '')
| -rw-r--r-- | 2019/talks/03.md | 155 |
1 files changed, 154 insertions, 1 deletions
diff --git a/2019/talks/03.md b/2019/talks/03.md index 9976ac8f..c703248e 100644 --- a/2019/talks/03.md +++ b/2019/talks/03.md @@ -8,4 +8,157 @@ type="video/webm"]] ### Download - [Video](https://mirror.csclub.uwaterloo.ca/emacsconf/2019/emacsconf-2019-03-emacs-development-update--johnw.webm) -- [Notes](https://mirror.csclub.uwaterloo.ca/emacsconf/2019/emacsconf-2019-03-emacs-development-update--notes--johnw.org) + +### Notes + +```org +. Built-in support for bignums + +In Emacs 27, you can now have arbitrarily long integer constants, or +operations that result in arbitrarily long integers. + +#+begin_src emacs-lisp +(let ((i 100329487239873259873254987235987345987435987)) (message "%d" (1+ i))) +#+end_src + +. HarfBuzz as the primary text-shaping engine, enabling support for + ligatures, stylistic sets, etc. + +In HarfBuzz there is a way to select styles, but we haven't yet exposed it +through Emacs Lisp. This isn't a hard job, and just requires someone to review +the HarfBuzz functionality and decide how to make it available in various +modes. For example, we'd probably like to see different ligatures in text +modes apart from programming modes, etc. + +Right now we use an old feature for ligatures called static compilations, +which is something we'd like to remove from the Emacs code base entirely. For +example, the current schemes fakes ligatures by creating a string containing a +particular symbol and masking out the set of characters you'd like to replace +with the ligature. Without HarfBuzz this was the only way; but now that we +have it, we can have real ligatures. We just have to tell the HarfBuzz +library: when you see "ffi", simply legate them, and it will be replaced by +the ffi ligature. + +For example, all you would have to say is, "for this text, display it as style +#7", in which case HarfBuzz can use what it knows about the font, which is +able to encode ligature replacements. We could also have a special text +property which indicates which style to use for a specific range of text. + +. The Cairo build is no longer "experimental" (i.e., buggy) + +This build had a lot of bugs, most of which have been fixed, so we've removed +the experimental tag in the configure script. + +In the Cairo scheme, you don't use the typical server/client mode. Cairo is a +text shaping and display library, and is something that Wayland wants to see +in applications. This is the path forward for graphical Emacs on Linux +machines. It's the means for Emacs to stay relevant in the future. Just like +the move from text-only to X11, this is a evolutionary move foward for how +text is displayed by Emacs. + +Importantly, to keep Emacs alive there are certain developments that need to +be tracked and supported. It's not enough to just play Lisp games and focus on +the applications that Emacs is able to run. But this will not keep Emacs alive +for years to come. As the core technologies of the system evolve around us, we +have to constantly adapt and add first class support for them. And mostly this +happens on the C side of development, not the Lisp side. + +Eli could use help from people to track and understand these technology, and +help us understand which ones are important now, and which are going to become +important in the near to distant future. HarfBuzz is a good example of one of +these; Eli had noticed that Windows has abandoned Uniscribe, and chosen a +library that cannot be called from C, only C++; and on Unix, the library we +were using for complex text shaping is no longer being developed or +maintained. These are two large libraries that we depend on that we're going +to lose support for; so HarfBuzz became a necessary path forward, and it's +important for the community to understand that for all the exciting +developments that happen on the Lisp side, there are absolutely essential +changes that also need to happen on the C side for Emacs to stay relevant, or +even functional! + +. Built-in tabs and tab bar + +On Linux machines, and in text mode, this provides built-in tabs, just as you +have in your browser. There is a tab-bar per frame; also, per window each tab +saves a window configuration, not just the window, so that when you press a +tab it can reconfigure the entire contents of the frame. + +(NOTE: This did not work for me on macOS) + +. Built-in image scaling and rotation without ImageMagick + +"ImageMagick is a Pandora's box" -- Eli + +We see quite a few crash bugs coming from inside ImageMagick, which forces us +to be both Emacs developers and ImageMagick developers, if we want to get +these issues fixed on our schedule. By replacing our need for ImageMagick, we +shift the work -- and the guarantee of stability -- into our own code base. + +. Portable dumping + +This is important because modern C libraries no longer do the tricks which the +original dumper relied upon. These tricks made assumptions about how memory +allocation works, since it functioned by taking a direct dump of the heap and +then mapping it back into memory later. But this is very difficult, because +ordinarily applications are not supposed to know how memory is laid out +exactly. glibc had been giving us privileged knowledge of the heap in order to +make this possible, but made the decision to stop supporting these special +hooks, which immediately broke Emacs and result in lots of quick patches being +necessary just to keep Emacs functioning. + +With the portable dumper, we can finally drop this abstraction leakage and +make ourselves immune to even which C library implementation is used. Now we +could even use MUSL, and still have support for snapshotting the load state +for fast recovery later. + +. Initial support for XDG spec + +~/.config, ~/.cache, ~/.local + +One of the problems with this is that parts of the XDG spec are incompatible +with the original Emacs directory location assumptions, making it tricky to +maintain backward compatibility, but since this is also the way of the future, +it's good to begin introducing this support now. + +. Enhanced NSM; more tight TLS security + +Network Security Manager (in lisp/net) is an intermediate layer that watches +all the network connections and makes sure that the security is OK. For +example, if you start a TLS connection, NSM validates all of the certificates +involved, that the authorities are OK, that they are not expired, etc. If +anything is wrong, it prompts the user as to see they want to use. This +separates out security validation from the network transport layer. + +. display-fill-column-indicator-mode as now a built-in feature + +This is now native in the display engine itself, so more text repainting +tricks are needed based on hooks or change functions, etc. Also, it now +maintains compatibility with other Lisp packages that modify the buffer, +whereas previously the set of tricks needed would often collide with other +tricks being performed with other modules. + +. so-long-mode now available for buffers with very long lines + +This mode makes buffers with very long lines more bareable. It turns off all +kinds of features that are known to slow down long lines even more. If your +lines are very very very long, instead of waiting for a minute for this to +redisplay, you may only have to wait for a few seconds. It doesn't solve all +the problems, it just knows about features that make the problem even worse, +and turns those features. But it only knows about basic features, like +font-lock, etc. + +. 'ngettext' for internationalization of messages + +This is a small step in the direction of internationalization. Making Emacs +properly localized is a /very/ large job. We even name commands such that the +name is a kind of documentation -- but the name is in English! + +This job is necessarily huge, but at leasts ngettext is a small step in that +direction. If a Lisp package, for example, wants to display messages based on +the locale, it can now provides strings to ngettext, and the proper string +will be chosen based on the local language. + +In a sense, this is more a flag to show people that we're thinking about this +direction in the future, even though there is still so much more to be done, +and as always, volunteers are more than welcome! +``` |