Zydeco for VS Code

This extension provides Zydeco syntax highlighting and starts the Cajun language server for .zy, .zyi, and .zydeco files. A .zyi file is the optional companion type annotation beside a .zy implementation; it holds one ordinary Zydeco term whose root must be a type, so it shares the language's highlighting and server analysis.

Features

• live syntax and name-resolution diagnostics;
• document symbols;
• clickable filesystem import paths;
• definition and reference lookup across imported source files;
• symbol rename across imported source files, preserving lexical name classes;
• inferred kind and type information on hover, with links to type definitions;
• documentation summaries in hover and full prose in completion;
• a persistent documentation panel with pinning, declaration/use type views, and checked scratch examples;
• compiler-aware semantic highlighting;
• full synchronization of unsaved editor contents.

Installing Cajun

Install the server with Cargo:

cargo install --git https://github.com/zydeco-lang/zydeco.git cajun --bin cajun --locked

The extension finds cajun on PATH. You can instead set cajun.server.path to an explicit executable path. If neither is available, the extension offers to run the Cargo command above.

Hover

To include a name or term's right endpoint when selecting hover information and choose a narrower column budget:

{
  "cajun.hover.inclusiveEnd": true,
  "cajun.hover.lineWidth": 72
}

cajun.hover.inclusiveEnd defaults to false; enabling it can make short names easier to hover near their right edge. cajun.hover.lineWidth is a positive integer, defaults to 100, and also controls completion type details. Changes apply to subsequent requests without reloading the window or restarting Cajun. Removing an override restores its default, and invalid values leave the last valid server settings in place. An already open popover may need to be dismissed and reopened.

Project documentation

Run Zydeco: Show Documentation from the command palette or editor context menu. The panel follows the cursor and offers Pin, Back, Source, and a type-view selector when the documented declaration differs from the current use. Pinning tracks a source occurrence across preceding edits; changing that occurrence invalidates the pin instead of retaining an old analysis.

Explicitly verified examples offer Check and Open scratch. Scratch files preserve file imports and use normal Cajun diagnostics, hover, and completion. Checking runs in a bounded compiler worker and never interprets the program. Results are discarded when their source revision changes.

See the language reference for annotations and semantic links, and the compiler reference for example checking and publication. The panel requires a Cajun server advertising documentation protocol version 1; ordinary hover and completion remain available to other LSP clients.

Formatting

Formatting policy comes from @[format(...)] annotations in the source, not from editor settings:

@[format(width(100), indent(4), layout(blank_lines))] begin
  ...
end

Each option applies to the annotated expression and everything inside it, and nested annotations override enclosing ones. Use @[format(verbatim)] to copy an annotated region's original source text unchanged.

Development

From this directory:

pnpm install
pnpm compile
pnpm test

Build Cajun from the repository root with cargo build -p cajun, then press F5 in VS Code. The development launch configuration supplies the workspace binary through CAJUN_SERVER_PATH.