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But for me personally, it has not only replaced vterm/eat but also any
other external terminal like kitty/Ghostty.
Having your terminal text just like a normal Emacs buffer opens up so many
possibilities and extension points that are just not available on any other terminal.
Even simple stuff like searching in the scrollback, then navigating and selecting+copying a paragraph only with the keyboard.
For every Emacs user that's so natural and fast in Ghostel while often cumbersome in other Terminals where I just reach to the mouse because it's easier.
Happy to answer any questions and also like to hear feedback positive or negative.
If you're an Emacs user and tried Ghostel and are still using Ghostty (or another external Terminal),
is there something Ghostel is missing or is it just because you want some processes to run outside of Emacs?
baokaola and I are also very active on GitHub, so feel free to open an issue if you have any.
Awesome project. Been using with doom for a while. How do you manage to get scrolling programs to work (eg Lazygit or Reasonix) where other emulators fail? Is it something special in your implentation or library that makes this work?
You have the full power of Emacs to your disposal.
I have never used WezTerm but from a quick look, it seems you can quickly copy text ace-jump style.
In Emacs you could use e.g. avy to do the same, but there is probably a bunch of other similar packages that do the same.
And additionally you're not restricted to just select/copy a word. You can freely move around and use e.g. expand-region or similar to quickly select more.
It's Emacs after all, the possibilities are endless ;)
How was integration for you guys? Was the integration easier for you guys since you have an established emacs system consuming terminal output with reasoned semantics over what goes where for existing subsystems (rendering, osc codes, etc)?
For libghostty-vt, since you're targeting a terminal TUI instead of an external subsystem (for example; for ghostty, you hit libghostty-vt -> GPU rendering, which is external), you still have to buy into terminal semantics. in my experience, since I was trying to replicate mosh with libghostty-vt as the parser, what happened was that my optimized re-rendering kept getting increasingly coupled to terminal semantics (and the UDP state update model too), otherwise I'd have to send the entire terminal grid over the network like, every time.
What are the tricks for making this both performant and not like, utter cancer? You have a harder issue here too (similar to tmux) in that certain optimizations are just not available to you, or you have to translate (literally geometrically) certain instructions
I'm not entirely sure what you're asking. But I'll answer to the best of my abilities:
For Ghostel, libghostty-vt is the source of truth and the architecture is essentially that we serve input to the PTY and the PTY serves output to libghostty-vt which builds out the state in the form of a terminal screen structure. The goal is then to keep the contents of an Emacs buffer up to date to this terminal screen without replace the entire thing every time we redraw. We make use of mainly two things in order to do as little work as possible:
- Scrollback is immutable and thus never has to be modified unless it's evicted, alt screen is activated, dimensions change etc.
- libghostty-vt maintains row level dirty flags that we scan to make sure we're only replacing lines that have actually changed.
So for the rendering part, we're only diffing the grid state against the buffer, not doing anything based on terminal semantics per se, parser events that draw to the screen are passed straight to the terminal handler. But of course, certain things we need to hook into such as directory and title changes, of clipboard events etc.
Might also add that we're using the direct Zig API, not the C API, which means we have access to things that aren't exposed in the C API.
I recently switched from vterm to ghostel, and it is generally much, much better - noticeably faster (e.g. fancy TUI apps that try to refresh the whole terminal every frame actually work), more reliable input handling, and a nicer ELisp API.
That being said, there are still some rough edges. Sometimes it fails to properly clear the terminal, leaving junk at the top of the buffer before the currrent prompt line. And on a couple of occasions it has totally frozen, with no fix other than killing the buffer and starting over.
Overall, it’s very promising and totally usable as a daily driver, but it needs a bit of polish and bug fixes before I would consider it mature.
Ghostel co-maintainer here: Understand if you don't have a repro, but if you ever have something actionable we'd love it if you filed an issue, or have the information get to us some other way.
The junk at the top of the screen sounds like it could be https://github.com/dakra/ghostel/issues/495 and it should be fixed on later versions. But maybe you're seeing another bug. The tricky part is replicating the libghostty-vt internal data into an Emacs buffer while only replacing the parts that need to be replaced. We have property based tests to exercise this a lot, but sometimes things slip through.
The latest released version as I'm writing this should have improved lifecycle handling, so maybe it also fixes some of your issues.
As you say, the project is still in the early phase so hopefully, we can iron things out over time.
I also switched from vterm and ghostel is much more responsive for me. Thanks for maintaining it! I use it everyday.
I do see a similar issue, where when I switch to the ghostel buffer and it wasn’t visible before, the text is scrambled. I’ll check if I can find a way to reliably reproduce it.
Yes, that sounds like the same issue. I’ll update to the latest version and see if it’s resolved. And thanks for your work on this package, it’s been a real game-changer for me!
Minor thing: vterm isn't pure ELisp either, it's a C module wrapping libvterm, so the speed difference isn't really "elisp vs elisp." Ghostel using libghostty directly probably just has a leaner render path. Still sounds like a real improvement though.
And I would also prefer if the link went to https://github.com/dakra/ghostel
instead of the documentation which is not that helpful if you don't know what the project is.
Been using it for bit over a month now. It's really nice that you can click on code references in Codex summaries and open them right there in Emacs buffers.
And not only mouse click of course, but you can use `ghostel-previous-hyperlink` (or ghostel-next-hyperlink) to quickly jump to the last hyperlink displayed.
It also installs a repeat-mode map, so if you see 3 url or file links as
output you can just `C-c C-p p p RET` and it will open the first link.
Repeat-mode chaining hyperlink jumps... nice trick. Reminds me of dired's repeatable commands back in the day. Emacs users find these tricks every decade, new package, same muscle memory.
Does ghostty have any features that makes it better than kitty in anyway? I keep seeing this all over the place, but I still don't understand why it's better than existing options.
Can someone help who's used both help me, what's the elevator pitch for this, why is it worth checking out?
Having used it for three weeks before coming back to Kitty, my conclusions were that it’s a better terminal for people who need a terminal but don’t ‘live in’ their terminal. Ghostty just feels really polished and ‘native’ and it’s obviously faster than, say, iterm or the stock term on macOS. So Ghostty is what I would now recommend to anyone who just wants a nice terminal without the goal of turning it into a highly personalized IDE, like Kitty allows you to do.
The only feature of Ghostty that I now miss in Kitty: setting the text size of each window pane independently. Oh and the slightly smoother quake terminal, even though I don’t use that much.
Ghostty makes some choices that I personally find bizarre. For one, on macOS, cmd+, opens config in textedit instead of in $EDITOR. Another is there isn’t a key action for moving panes; you need to use the mouse. At least half of the config options are platform-specific. And weirdest of all scripting is limited and can only really be done with (get this) AppleScript.
So, like I surmised (and I could be wrong, of course), Ghostty is just a nice terminal that lives alongside your other apps; Kitty is powerful enough to practically act like a second desktop environment (that is also cross-platform).
Of course, this post is about libghostty, the underlying term emulator library. And that is an amazing contribution to the ecosystem! Zmx, herdr, soon neovim, now emacs, hopefully someday Zed – so many things can now embed an amazingly performant terminal
Thank you so much for building this. I've been wanting something just like this and I'm trying it now and it's amazing. I was struggling with vterm and now this might become my daily driver.
Same path here, went vterm -> eat -> now this. Eat was fine but scrollback and rendering perf got rough on long-running tmux-in-emacs sessions. Ghostel handling that way better since it's just shelling out to libghostty instead of Emacs trying to reimplement a terminal emulator in elisp.
Ghostty has crashed nightly for me with ~10 terminals open across a few windows. So, I haven't been able to run it nor would I want to
embed it inside anything I daily drive.
I have opened right now about a dozen Ghostty windows and about 20 tabs in each window, i.e. more than 100 shell instances.
I have started in as many of them as I could, before becoming too bored, a "ls -lR" on a file system with many millions of files.
I could not see any problem, much less any crash. I have been using Ghostty for a few months, very intensively, all day long, and I have not seen any crash or other suspicious behavior.
If you have seen a crash, perhaps there was either some specific version of Ghosstty that had a bug, or, more likely, some weird interaction with some other software that you have, and which might be buggy, e.g. the GPU driver. (I am using an NVIDIA GPU.)
Just commenting to say I've had the same experience. Been using Ghostty since (I was aware of) its release and it has been buttery smooth ever since. I occasionally see people talking about crashing or other issues they've had with Ghostty but I've not seen anything of the sort.
It would be nice to have some practical examples of how efficiently use its different input modes. On the surface the reasoning is straightforward - a terminal wants every keystroke. The editor also wants keystrokes for its own commands. These two desires are irreconcilable, so any editor-embedded terminal must have a way to switch "who owns the keyboard." That switch is a mode. There is no escaping it.
But like people coming to Emacs from Neovim may get confused why is nvim +term has only two modes, but this one has 5, what's the point? Without clearly understanding the problem, the knee-jerk reaction might be "this thing is an over-engineered BS", while in truth Ghostel isn't more complex because it's over-engineered - it's more complex because it solves more of the problem - the extra modes are opt-in tools for tasks nvim simply doesn't address. But it's not super clear how in practice use that leverage efficently.
True. I'll have to update the documentation with some examples (and/or make a video?).
I know you know them but I list the 5 modes quick here for readers:
- semi-char: The default, where most keys go to the terminal but some common Emacs prefixes (M-x, C-c) go to Emacs
- char-mode: ALL keys go to the terminal. This way you can run e.g. Emacs inside Emacs.
- copy-/emacs-mode: This makes the whole buffer a pure read-only Emacs buffer and all keys go to Emacs. The difference between copy and emacs-mode is that copy freezes the terminal output (comes originally from vterm), while in emacs-mode new output keeps coming in (adopted from eat).
- line-mode: It's like `M-x shell`, everything goes to Emacs but it's not read only but you can type text on the prompt. But nothing is send to the terminal until you press return.
> why is nvim +term has only two modes, but this one has 5
I haven't used the neovim terminal, but I guess you can compare vim insert-mode with semi-char and normal-mode with copy-mode. And surely they have a char-mode as well, or can you not run nvim inside nvim (without having to press some quote key all the time)?
That would leave only line-mode as the odd one out.
> But it's not super clear how in practice use that leverage efficently
As with all Emacs things, that's highly personal.
Currently, I use semi-char mostly and switch to copy-mode to select/copy stuff.
Question: if I don't use TUIs or millions of lines of scrolling text, what am I missing by not using these newer terminal implementations? I use mintty on Windows and am pretty happy with it.
For me is the ability to maintain the same keyboard workflow, no matter if I’m dealing with files or terminal (switching buffers, navigating/searching/selecting/copying/pasting text, etc.), I get to keep the same set of shortcuts and mental model. And i get to do some small automation on top of it with elisp, which I already do for the rest of my editor anyway.
Exactly as you say, the greatest difference with the recent generation of video terminal emulators that use the GPU through OpenGL or the like, is the much greater rendering speed, which becomes very noticeable with millions of lines of scrolling text, especially if you use high-resolution monitors.
Unfortunately, millions of lines of scrolling text are no longer unusual, especially when you frequently compile big software projects. The use of high-resolution monitors has also been normal for many years.
Instant window rendering is addictive, so now I would never return from a fast terminal emulator like ghostty to an older video terminal emulator. The last terminal emulator that I had been using before ghostty was kitty, which was also pretty fast in comparison with traditional terminal emulators, but I like ghostty more.
Honestly not sure. I used ghosty and others for awhile but had continuous issues of it not passing a compatible term variable so a lot of tuis would break.
This is normally a problem only when connecting to a remote computer through ssh, if you have not installed there the terminfo entry for ghossty or kitty or whatever recent video terminal emulator you are using.
If you do not want to or you cannot install the terminfo data, there is the easy workaround to put in your shell initialization script on the remote computer something like "export TERM=xterm-256color".
Ghostty aims to be completely compatible with xterm, so everything should work fine after setting thus TERM, only the newer features of ghostty will not be available.
For all Emacs package updates, it's best of course to check the source what's changed and then you can compile yourself.
PS, I also think Emacs is one of the few ecosystems where people actually
check what changed. It's not like npm where you have a million of deps unreviewed pulled in.
Personally I use borg and always at least quick check what changed, and most Emacs
package managers have a similar feature.
Fwiw, in all my Ghostel updates recently, the Zig module failed to compile, with an error message from Zig about a line in the module source. I have a fairly up to date Zig installed via Homebrew.
I didn't have time to fix it so downloading the binary module has been the only option.
I had the same problem with vterm when I first tried it. The C module failed to compile, with a compiler error about a line in the source. As there was no downloadable binary module I fixed that one.
Every emacs-integration post makes fast TUI redraw sound trivial, but has anyone actually benchmarked Ghostel against alacritty or kitty on something brutal like htop with high refresh, not just vterm? Emacs display engine's own overhead has to show up somewhere.
baokaola and I actually wanted to do a "Show HN" next week, but looks like someone was faster submitting the link.
Have a look at the GitHub repo which is a bit nicer for a quick overview: https://github.com/dakra/ghostel
To add some context, Ghostel is a terminal emulator for Emacs powered by libghostty-vt.
There's a feature comparison vs vterm and eat: https://dakra.github.io/ghostel/#ghostel-vs-vterm
And here is a gist with images to compare performance and correctness: https://gist.github.com/dakra/4a0b76ebcf5d52338e134864378465...
But for me personally, it has not only replaced vterm/eat but also any other external terminal like kitty/Ghostty.
Having your terminal text just like a normal Emacs buffer opens up so many possibilities and extension points that are just not available on any other terminal.
Even simple stuff like searching in the scrollback, then navigating and selecting+copying a paragraph only with the keyboard. For every Emacs user that's so natural and fast in Ghostel while often cumbersome in other Terminals where I just reach to the mouse because it's easier.
Happy to answer any questions and also like to hear feedback positive or negative.
If you're an Emacs user and tried Ghostel and are still using Ghostty (or another external Terminal), is there something Ghostel is missing or is it just because you want some processes to run outside of Emacs?
baokaola and I are also very active on GitHub, so feel free to open an issue if you have any.