RMT Language Server

Editor integration for completion, hover, definition and code actions.

What it covers

The RMT language server provides diagnostics, navigation, completion, and code actions from the same source model as the CLI and compiler. Editor feedback is therefore an early view of the same errors, not a separate grammar.

Public building blocks

tools/rmt-language-server/server.js processes documents and requests.
tools/rmt-language-server/protocol.js defines public message shapes.
tools/rmt-language/diagnostics.js supplies normalized RMT diagnostics.

node tools/rmt-language-server/server.js.
Completion, hover, definition and Code Actions.
Snippets for app, component and route structures.

Editor setup

node tools/rmt-language-server/server.js

The server supports VS Code, JetBrains, Neovim and Helix through stdio. Snippets such as rmt-app, rmt-component, rmt-route and rmt-template-dom speed up new files. The relevant schemas are xtend.rmt.language-server.v1, xtend.rmt.editor-packaging.v1 and xtend.rmt.snippet-catalog.v1.

VS Code also contributes XTendRMT: Show vNext Primitive Apply Experience and XTendRMT: Run Active RMT Lint. Problem-matcher workflows use xt rmt lint app.rmt --format problem-matcher --fail-on warning; debug configurations are available as a template at tools/rmt-editor/vscode/templates/launch.json.

Orchestration DX

The language server adds completion, hover and document symbols for validation, animation and transition. That works for native .rmt files and for JSON/Core-like documents with validations, animations and transitions. Effects such as fade, crossfade, slide-left, slide-right, slide-up, slide-down, scale, pop, zoom, flip, fade-blur, shared-element, layout-flip and none, plus validation rules such as required, email, minLength, maxLength and pattern, are explained in the editor.

The complete keyword and operator contexts live in the RMT Reference.

New snippets:

rmt-vnext-validation
rmt-vnext-animation
rmt-vnext-transition
rmt-vnext-maraca-orchestration-app

node scripts/run_xtend_tests.js rmt-completions rmt-navigation rmt-vnext-tooling rmt-editor-packaging --json

Recommended workflow

Open an .rmt file through the editor integration, resolve parser errors before semantic diagnostics, and confirm critical changes with the CLI gate. Restarting the editor must not produce a different diagnostic set.

Shared project index

Workspace symbols (workspace/symbol), definitions, import navigation and textDocument/references use a shared in-memory index. It includes closed RMT files in every workspace folder. Open buffers take precedence over disk content; closing a buffer reloads the file. Clients should send workspace/didChangeWatchedFiles for external changes and workspace/didChangeWorkspaceFolders when roots change. Older document versions are ignored. Positions use UTF-16, as required by the existing source model.

Symbol identities contain the project, relative file, domain and declared scope. Inserting lines preserves identity. Moving a file changes identity; impact reports compare both snapshots so deleted relationships remain visible.

const { createProjectIndex, computeImpact } = require('@ccslabs/xtend-compiler/project-index');
const index = createProjectIndex({ rootDir: '/absolute/project', profile: 'rmt' });
index.build();
const matches = index.searchSymbols('orders');
const references = matches.length ? index.references({ symbolId: matches[0].id }) : [];
const snapshot = index.snapshot();
index.dispose();

The same API is exported as @ccslabs/xtend/project-index. updateDocument accepts a URI, text and increasing version; closeDocument, refreshDocument and removeDocument manage subsequent changes. Snapshots contain concrete document, symbol, reference, relationship and coverage records with provenance.

xt index build --root /absolute/project --profile rmt --json
xt index symbols orders --root /absolute/project --json
xt index references --symbol '<symbol-id-from-symbols>' --root /absolute/project --json
xt index build --root /absolute/repository --profile repository --out /tmp/base-index.json --json
xt index impact --root /absolute/repository --base /tmp/base-index.json --changed tests/fixtures/input.json --json

The repository profile adds static JS/TS imports, package exports, curated schema contracts and suite registrations from scripts/run_xtend_tests.js. TypeScript is optional for RMT navigation; install it in the project to enable module analysis. The editor profile does not load TypeScript, the schema inventory or test modules. Neither profile executes project modules or resolves over the network. The repository report lists browser, Node and type export targets separately, together with missing targets and computed dependencies.

RMT compilation remains file-local. Import paths navigate to files within the existing resolver boundaries. A matching declaration in an imported file may appear as a candidate in the index report; it does not become a confirmed definition/reference and cannot remove compiler diagnostics. Incomplete input offers declarations retained by the parser, with an explicit incomplete status.

Impact reports retain explanation paths from the base and current snapshots, unknown mappings and possible duplicate suite implementations. They never skip, select or merge gates. A report with no identified suite does not establish that no tests are required. Rename, formatting, semantic tokens and full JS/TS symbol analysis remain separate work.

--cache explicitly enables .project-index-cache/snapshot.json. The cache is ignored by source scans and invalidated by source, configuration, inventory or analyzer-version changes. It can be deleted and rebuilt at any time; distributable packages contain no repository snapshot. For measurements and verification run npm run test:project-index; runtime values are observations, not timing gates.

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