The VS Code extension

Language support for .aui and .auis, backed by the same compiler the Unity importer runs. A squiggle in VS Code is the line the Unity console would print.

Install

You receive the extension as a .vsix alongside the package.

1. In VS Code, open the Extensions view.
2. From the ... menu, choose Install from VSIX, and pick the file.
3. Reload when prompted.

Or from a terminal:

code --install-extension aui-0.5.1.vsix

Requires the .NET 8 runtime (or newer) on your PATH as dotnet. If it lives somewhere else, set aui.dotnetPath.

Open the right folder

Open the world project folder: the one containing Assets/. The server reads Assets/AUI/AuiSettings.asset for the language folder, the default language and the component and icon folders, exactly as the Unity editor does. Without a settings asset it falls back to Assets/AUI/Lang, or any folder called lang.

A view opened outside that tree brings its own folder in, so a sample still resolves.

What you get

Diagnostics

Live, for views, stylesheets and language files. Every diagnostic code appears here first.

Shared files (the theme, a linked sheet, en.json) show the union of what every view found, so "class not used" on a shared sheet only appears when no view uses it.

Completion

• tags, and nested views by name
• attributes for the current tag, with the ones you already wrote left out
• translation keys, with their text, so you pick by meaning rather than by name
• classes, labelled with the sheet they come from
• icons, page ids, bindings, handlers (from the view and from its .cs), href paths
• in stylesheets: selectors, properties, values, var(--x), sprites, eases
• </ completes the innermost open tag

Hover

A key shows every language's text. A binding shows its C# type and the generated property. A handler shows its signature and where it is defined. A class shows its declarations, a variable its value, a nested view its bindings. Elements and properties show their documentation.

Go to definition

A key jumps to each language file. A class or variable to its rule. A handler to its C# method. A nested view to its file. page= to the page. An icon to the SVG. href to the sheet.

Find references and rename

Works across the whole workspace: classes (every view and sheet), keys (every view and every language file), variables, and per-view bindings, handlers and ids. Renaming from inside a language file works too.

This is the feature that makes renaming a translation key painless.

Quick fixes

• "did you mean" replacements for a misspelled tag, attribute, property, class or icon
• insert a missing ;
• create a missing key in the default language, or in every language at once, with the caret landing on the new value
• add a key to just the languages that lack it
• create a missing nested view or stylesheet file
• create a handler method in the view's .cs
• remove an unused rule

Format Document

Shift+Alt+F (or format on save) for both .aui and .auis. The house style prefers newlines over inline packing:

• every child element on its own line, the closing tag on its own; an element whose only content is text stays on one line (<text>Debug build</text>)
• attributes on one line while the tag fits in 100 columns, otherwise one per line at one extra indent with the > or /> on its own line. Never aligned with padding spaces, and alignment padding in the source is collapsed
• a stylesheet rule always expanded: selectors on one line, one declaration per line, the brace on its own, one blank line between rules and none inside a block. <style> blocks inside a view get the same treatment at their own indent
• comments kept verbatim and re-indented; one blank line between things is kept, more collapse to one

Two spaces, LF, whatever the editor's tab settings say, so every file in a project looks the same. A file with a syntax error is left exactly as it is: formatting never moves a mistake around.

Editor extras

• colour swatches and a picker for stylesheet colours
• inlay hints showing the default-language text after key="..."
• document links on href and src
• document outline for views and sheets, workspace symbols for views, classes and keys
• auto-closing tags, indentation between tags, and snippets (view, panel, button, tabs, repeat, rule, state, ...)
• file icons for .aui and .auis in the explorer and tabs

Commands

Command	What it does
AUI: Show Generated C#	previews the class the view generates, refreshed as you type. Also a button in the editor title bar
AUI: Restart Language Server	when something is off

Show Generated C# is the fastest way to answer "what is this binding called in C#" without saving and switching to Unity.

Settings

Setting	Default	Meaning
aui.serverPath	bundled	path to aui-lsp.dll, or a self-contained aui-lsp
aui.dotnetPath	dotnet	host for the dll
aui.autoClosingTags	true	> inserts the closing tag, </ completes it
aui.inlayHints.translations	true	show text after key="..."
aui.trace.server	off	protocol trace in the output channel

If it does not start

1. Check dotnet --version reports 8 or newer.
2. Run AUI: Restart Language Server.
3. Set aui.trace.server to verbose and read the AUI output channel.
4. Confirm you opened the project folder, not a subfolder of it.

Next

• The language server for running it outside VS Code.
• Diagnostics for what the squiggles mean.