Zed Julia

This extension adds support for the Julia language in the zed editor.

Quick links

• Contributing
• Installing Julia / Zed / Zed Julia extension
• Configuring the Julia executable for tasks
• Running code in the REPL
• Using Zed in the REPL
• Customizing syntax highlighting

Installing Julia / Zed / Zed Julia extension

1. Install Julia for your platform: https://julialang.org/downloads/
2. Install Zed for your platform: https://zed.dev/download
3. Start Zed.
4. Inside Zed, go to the extensions view by executing the zed: extensions command (click Zed->Extensions).
5. In the extensions view, simply search for the term julia in the search box, then select the extension named Julia and click the install button. You might have to restart Zed after this step.

The Julia Zed extension looks for your Julia binary in the standard locations. Make sure that the Julia binary is on your PATH.

Configuring the Julia executable for tasks

By default, Zed tasks (like running tests) use the julia command from your PATH. You can customize which Julia executable is used by setting the julia environment variable:

1. In your shell configuration (.bashrc, .zshrc, etc.):

   export julia="/path/to/custom/julia"

2. When launching Zed from the terminal:

   julia="/path/to/custom/julia" zed .

3. Using direnv (automatically supported by Zed):

   • Create a .envrc file in your project root with:

     .envrc

     JULIA_HOME="path/to/julia/directory"
     PATH_add "$JULIA_HOME/bin"
     export julia="$JULIA_HOME/bin/julia"
     

   • Run direnv allow to approve the file

This allows you to use different Julia versions for different projects or to specify a Julia installation that's not on your PATH.

Running code in the REPL

This section describes how to select Julia code in the editor and run it in Zed's integrated terminal. This is more of a workaround than a full integration. Currently, there is no inline code execution as in VSCode. On the other hand, the Language Server is not required to make this work.

1. Open a .jl file in the editor.

2. From the Command Palette, run open in terminal. This opens a new terminal in the worktree root (where the Project.toml lives). You can also right-click in the editor and use the context menu or press ctrl-shift-` as defined in the json example below.

3. In the terminal, start the REPL with julia --project.

4. Now it's time to select some code in the editor, copy it to the clipboard, paste it into the terminal, execute it, and go back to the editor. To make that less tedious, add one or more of the following key bindings. Change the ctrl-shift-f10/11/12 combinations to your liking.

   Note: interacting with the terminal requires to send keystrokes. In the examples, cmd-v is used to paste code. Please adjust this binding for your operating system.

   // Zed key map file, usually ~/.config/zed/keymap.json
   [
     {
       // Set the focus back to the editor without hiding the terminal.
       // This is an auxiliary binding used by other bindings.
       "context": "Terminal",
       "bindings": { "ctrl-shift-`": "terminal_panel::ToggleFocus" }
     },
     {
       "context": "Editor && mode == full",
       "bindings": {
         // Open a new terminal and change to the worktree root directory.
         "ctrl-shift-`": "workspace::OpenInTerminal",
   
         // Execute the whole line the cursor is on and move the cursor to the next line.
         // Invoke this binding repeately to run line by line.
         "ctrl-shift-f10": [
           "action::Sequence",
           [
             "editor::SelectLine",
             "editor::Copy",
             "editor::MoveRight",
             ["workspace::SendKeystrokes", "ctrl-` cmd-v ctrl-shift-`"]
           ]
         ],
   
         // Execute the enclosing top level block e.g., a function definition.
         // Note the additional keystroke "enter" to actually execute the code.
         "ctrl-shift-f11": [
           "action::Sequence",
           [
             "editor::SelectEnclosingSymbol",
             "editor::CopyAndTrim",
             ["workspace::SendKeystrokes", "ctrl-` cmd-v enter ctrl-shift-`"]
           ]
         ],
   
         // Execute the paragraph (a block surrounded by blank lines).
         "ctrl-shift-f12": [
           "action::Sequence",
           [
             "editor::MoveToStartOfParagraph",
             "editor::SelectToEndOfParagraph",
             "editor::Copy",
             ["workspace::SendKeystrokes", "ctrl-` cmd-v ctrl-shift-`"]
           ]
         ]
       }
     }
   ]

Using Zed in the REPL

Zed is currently not on the list of Julia's predefined editors. You can add it to your ~/.julia/config/startup.jl:

atreplinit() do repl
    InteractiveUtils.define_editor("zed") do cmd, path, line, column
        `$cmd $path:$line:$column`
    end
end

Set the environment variable EDITOR (or VISUAL or JULIA_EDITOR, whatever you use) to zed --wait. Then, using InteractiveUtils.edit etc. will open the document in Zed.

Customizing syntax highlighting

You can change the foreground color and text attributes of syntax tokens in your ~/.config/zed/settings.json, for instance:

{
  "experimental.theme_overrides": {
    "syntax": {
      "comment.doc": {
        "font_style": "italic"
      },
      "function.definition": {
        "color": "#0000AA",
        "font_weight": 700
      }
    }
  }
}

See Syntax Highlighting and Themes and Tree-sitter Queries for further details.

Syntax tokens are called captures in tree-sitter jargon. The following table lists all captures provided by zed-julia. Some captures have default values (defined in Zed's color themes) and the other captures fall back to one of the defaults. Depending on your color theme, some captures may be set to the editor's foreground color or to a very similar one. In this case, try to assign a different color to improve the contrast.

Capture	Is there a default value?	Note/Example
boolean	yes
comment	yes	line or block comment
comment.doc	yes	docstring
constant.builtin	no, falls back to constant	core julia built-in
function.builtin	no, falls back to function	core julia built-in
function.call	no, falls back to function	name of the called function
function.definition	no, falls back to function	name of the defined function
function.macro	no, falls back to function	name of the macro
keyword	yes
keyword.conditional	no, falls back to keyword	if, else
keyword.conditional.ternary	no, falls back to keyword	? :
keyword.exception	no, falls back to keyword	try, catch
keyword.function	no, falls back to keyword	function, do, short function definition: =
keyword.import	no, falls back to keyword	im/export, using, module definition
keyword.operator	no, falls back to keyword	in, isa, where
keyword.repeat	no, falls back to keyword	for, while
keyword.return	no, falls back to keyword	return
number	yes
number.float	no, falls back to number
operator	yes
punctuation.bracket	yes	(), [], {}
punctuation.delimiter	yes	,, ;
punctuation.special	yes	string interpolation: $()
string	yes
string.escape	yes	escape sequence
string.special	yes	command literal
string.special.symbol	yes	quote expression
type	yes
type.builtin	no, falls back to type	core julia built-in
type.definition	no, falls back to type
variable	yes
variable.builtin	no, falls back to variable	core julia built-in: begin and end in indices
variable.member	no, falls back to variable	example: in foo.bar, the member is bar