Language server

The Iris language server uses the Rust parser, semantic model and reader. An editor starts the iris executable with one argument, lsp, and communicates through framed LSP messages on standard input and output. Errors go to standard error. The editor owns executable discovery and installation.

Connect an editor

Build the CLI. Configure your editor’s language-server executable as iris, with arguments ["lsp"], or supply the absolute path to the built executable. The editor can use the project directory as its working directory; document identity comes from URIs. The JetBrains plugin starts the server for you. A VS Code extension that combines the grammar and an LSP client is planned.

The server analyzes open buffers, including unsaved edits. It supports incremental synchronization, UTF-16 positions by default, and UTF-8 when the client offers it. Edits trigger analysis after a 150 ms debounce. Closing a document clears its diagnostics.

Features

• Parse and resolution diagnostics with stable error-code links, including syntax errors.
• Hover for keywords, types, functions and names, with inferred value types and depths.
• Completion for statement keywords, visible names, named types, layouts, functions and host constants.
• Go to definition, find references, and rename within the current document. Rename checks for collisions and preserves reference targets.
• Inlay hints for definitions, an outline of repeats, sections and instances, folding, and semantic tokens.
• Document and range formatting using the same style as the CLI.

Hover and hints do not guess: a fact the server cannot determine is shown as unknown, and several possible definitions are listed and marked ambiguous. Rename requires a reader spec without parse or resolution errors. Navigation uses the available semantic model even when the source has an error. Features available in an editor also depend on its LSP client.

Read a sample while editing

A directive comment asks the server to read a sample with the whole reader spec:

# iris: sample samples/small.txt

Save a file at samples/small.txt relative to the reader spec’s directory. On open and accepted reader-spec edits, the server reads it and merges any runtime errors with the document diagnostics. A successful sample gets a hover summary and inlay hint with entry names, types, scalar values and shapes. The previews are truncated for large data; the read itself is complete.

A directive can add instance=2 or param NAME=VALUE. Double quotes delimit components containing spaces; backslashes are literal. Paths must be relative and resolve from a local file URI. Untitled buffers cannot resolve sample paths. Directives are ordinary comments to the Iris language and to Gecode.

The server rereads samples on reader-spec edits, without watching sample files. After changing only an input file, edit the reader spec or close and reopen it. Obsolete reads are cancelled and their results are discarded. See the server README for directive syntax, preview limits, and protocol details.