WEBVTT
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Hello and welcome to this talk.
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The title of this talk is a tour of vterm,
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a fast and fully featured terminal emulator
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inside GNU Emacs.
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So let's try to understand what we mean
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with "fast and fully featured."
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To do that we'll compare vterm
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with the packages which are built in Emacs,
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mainly, term.
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So let's jump into the vterm.
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So this is a vterm buffer
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and this is a ansi-term buffer.
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What I'm going to do now is
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first I'm going to prove to you
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what we mean by fast.
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To do that, let me open a large file display on screen--
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a large file, this is about one megabyte of data--
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and let me time that.
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It takes about 0.6 seconds with vterm.
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Let's do the same with with ansi-term.
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Well, we already see the difference.
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So I will use this time to tell you
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what's different, and what is vterm exactly.
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vterm is a terminal emulator
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built on top of an external library.
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The library is called libvterm,
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and is the same library used by Newton
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for their own terminal emulator.
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It's a C library, and this is what gives us
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a lot of good features. First, the speed.
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Time spent here, 0.6, is essentially
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the time that it takes to:
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1. convert the Emacs representation of text
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into the vterm representation of what is a string,
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and 2., into actually displaying that,
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and that can take time
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if there's fontification involved.
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So these are the 0.6 seconds there.
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As we say, in ansi-term, that's much more time.
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It's much slower. So the terminal will feel
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much snappier, much faster.
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But that's not the main benefit or the only benefit
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of using this external library vterm.
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The second big benefit is that
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vterm has support for all the escape codes
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that xterm has support for,
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so vterm is essentially as running xterm
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inside an Emacs buffer. So let's see that.
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For example, let's start by looking
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at the support for colors.
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We have support for all the colors out of the box.
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We don't have to do anything.
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And if we did the same here, well,
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we have only 20 colors.
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There's a way to get all the colors,
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but it's much more involved.
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But this is not where vterm shines.
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We can run all the commands that we want.
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htop, ncdu, everything runs here.
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Also this title, it's a fairly complicated
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manipulation of the window
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and it will not work here.
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It just doesn't work actually.
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Now the terminal is probably messed up. Yes.
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So using this external library
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removes the burden from the developers
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of having to implement support
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for all the escape codes.
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We just use those.
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So in many ways, running vterm
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is running xterm inside Emacs,
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but it's better than that because,
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since this is an Emacs buffer,
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we can enjoy a lot of features from Emacs
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as well as a tighter integration
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with Emacs itself.
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For example, as you see here,
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the title of my buffer is from the directory I'm in.
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So let's go to my tmp.
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The title will change.
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So there's information being exchanged
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between vterm and Emacs.
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And of course, the title is not the only place
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where information is exchanged.
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I can find a file and I will be in the directory
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where my terminal is.
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This feature is also available in ansi-term,
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and it works also on vterm,
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and it follows me. So if I go to tmp,
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I'll get the tmp.
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If I ssh to a remote server,
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it will work also on remote servers as well,
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which is a very nice way to edit files remotely
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while we're working on a shell.
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And second, while vterm is not an Elisp interpreter
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like eshell, what we can do is
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we can still run Emacs functions.
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So for example...
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that requires some configuration.
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vterm command (message "hi")
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as you see there's a "hi" here.
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So what I'm doing is I'm executing
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the Elisp function hi.
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I can drop that and turn it around,
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hash function to run Elisp functions.
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Or another one, find-file, same.
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We call this feature "message passing,"
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and it requires some configuration
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on the Emacs side as well as in the shell side.
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It's important to stress
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what's the nature of vterm.
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For instance, every time I'm sending a key binding,
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it's not immediately clear if my intention is
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to send it to the shell or to Emacs.
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So vterm implements some reasonable defaults,
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but at the moment it's mainly packaged
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to display characters on a screen.
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So for example, if you're using evil,
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the editing commands in evil
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will not work immediately.
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There's some work to be done
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and integration can be improved on that side,
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but sometimes we really want this to behave
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exactly like a Emacs buffer.
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We want to be able to search.
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If I try to get it to search,
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it will not work.
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I will send it to the shell.
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So to do that, we enabled vterm copy mode.
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As you see, copy mode, and now this buffer
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is essentially a fundamental buffer.
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I can move around. I can search.
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So it must have... I can do everything I want.
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And there are additional features.
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For example, I can jump around all the prompts.
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I find this extremely useful,
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because I can copy updates from my programs.
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What I always have to do is
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I have to Google some errors.
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So what I do is I select that
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and I have my keybinding in Emacs conf,
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and I'm Googling what I have to Google.
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So this is very nice and if I...
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now that I have selected something,
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if I just press return,
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I will go back to my normal editing mode
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with the text copied, so I can paste it back.
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So it's a quick way to interact with copy
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and interact with the output of a buffer.
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So finally, let's discuss how to actually use vterm.
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Let's circle back, let's go,
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and let's look at the GitHub repo
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where development is happening.
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vterm is available in MELPA,
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but since it's leveraging the power
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of an external module,
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you must have Emacs compiled
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with support for modules,
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and many distros like Ubuntu, Debian,
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that's not there. So you have to
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get Emacs with support for modules:
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compiling or getting images somewhere else.
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And also, the first time you are going to use this,
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which works only on Mac or GNU Linux systems,
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Emacs will try to find and compile this module,
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so it's important. This requirement is important.
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If you're using Windows, well,
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it's not available and will not work.
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So to conclude, I want to just advertise this page.
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If you have problems, look at the issues
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and open an issue in case.
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We'll try to help you.
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We are very excited about vterm,
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and I think it's a transformative
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terminal experience inside GNU Emacs.
