Novus Language for VS Code

Editor support for the Novus programming language (.nv files): the client of the language server novus-lsp (written in Novus; see Installation), run/build commands and syntax highlighting, plus highlighting for its web components (.nvh: HTML with <?nv ?> blocks, {expressions}, {#if}/{#for} blocks and @event/bind=/class: directives) and Run/Build for them. Markdown pages with Novus in them (.nvmd: a --- frontmatter, an <?nv ?> header, {expressions}, {#if}/{#for} blocks, <Component> tags and ```nv fences) are highlighted as Markdown with embedded Novus; the compiler does not read them, the dependency nvh-markdown generates .nvh files from them.

The cascade operator receiver..a()..b = 1 (every section runs against the receiver, which is the value) has its own token (keyword.operator.cascade.novus), completion after .. and the formatter keeps .. tight and indents ..section lines like a method chain.

A raw C block c { ... } (with $name for a Novus variable) is highlighted as C inside Novus; the language server treats it like a block comment: no diagnostics, completion or semantic tokens in it, the formatter leaves it as it is. import project (the values of project.nv) is a known module for completion and hover.

Installation

The extension is a client: the language features come from the novus-lsp binary.

1. Build it in the repository (make lsp writes build/novus-lsp) or take novus-lsp-<target> from a release, rename it to novus-lsp and put it on the PATH.
2. Build and install the extension: npm install && npm run package, then Extensions: Install from VSIX....

The extension finds the server through the novus.server.path setting, then build/novus-lsp in the workspace, then novus-lsp on the PATH. If it finds none it offers to open the setting or to use the previous TypeScript server (novus.server.implementation), which completes with its own short snippet list: the full catalogue of snippets comes from novus-lsp. Other editors (Neovim, Helix, JetBrains, ...) need only the command novus-lsp --stdio; see the documentation site, page Editor support.

Features

• Syntax highlighting – TextMate grammar covering the complete concept syntax: packages, imports, methods, define class|enum|interface|abstract|annotation, based, constructors, annotations, accessors (: get, set), generics (array<T>), string interpolation (${…}), comments and operators.
• Semantic highlighting – classes, enums, interfaces, methods, fields, parameters, locals and modules are colored by what they are, not by how they look.
• IntelliSense
  • completion for keywords, types, methods, fields, locals, enum constants, modules and annotations, context aware (top level / class body / statement / after . / after : / after @)
  • object initializers: completing a class offers Key{…} which expands to Key{ field=… } with a placeholder per field, and inside Key{ … } (or @Annotation{ … }) the remaining field names are suggested
  • signature help with parameter highlighting (including overloads)
  • hover documentation (/// and /** */ doc comments are picked up)
• Diagnostics – syntax errors with recovery, unresolved names, duplicate declarations, methods without a body, assignments to final values, unused locals, deprecated members.
• Auto import – symbols from other packages are offered in completion and inserted together with the matching import <package> line; using an unimported symbol yields a warning with an Import '…' quick fix (plus Add all missing imports). Go to definition and hover work even before the import is added.
• Navigation – go to definition, find references, document highlights, rename (workspace wide), outline / breadcrumbs, workspace symbol search, folding.
• Formatter – Format Document / Format Selection (and editor.formatOnSave) normalize indentation, spacing and blank lines in the style of test/syntax.nv (a + b, if (x) {, Key{field="value"}, array<Person> friends, name: get, set). Line breaks, comments and strings are left as written, and it also works on files that do not parse yet.
• Run & Build – Novus: Run Novus File (editor play button, Ctrl+Alt+N) compiles and runs the current file (novusc run); Novus: Build Novus File compiles it to a native binary (novusc build). Both use build/novusc in the workspace, then novusc on PATH, or novus.executablePath.
• Snippets – main, method, class, enum, interface, for, if, field, @Deprecated, … (89 of them, offered by the server through completion; snippets/novus.json is generated from the server's catalogue with make snippets)

The whole workspace is indexed, so symbols defined in other .nv files are available for completion, navigation and rename.

Settings

The settings of the TypeScript server (novus.diagnostics.enabled, novus.diagnostics.undefinedSymbols, novus.diagnostics.unusedVariables, novus.format.namedArgumentSpacing) still apply when it is selected. The full list with every novus.pureline.* key is on the documentation site, page Language server.

Language notes

Novus is self-hosting: novusc, written in Novus, compiles Novus (and itself) to C and is the only implementation. It covers all of test/syntax.nv (a golden test): classes, inheritance, interfaces, abstract classes, enums, annotations, overloading, ${} interpolation, comments, modules (json, path, os, http) and the free builtins (readFile, writeFile, fileExists, removeFile, readLine, args, parseInt, parseFloat, chr, ord, typeOf, exec, env, exit, platform). Hover texts still mark the few remaining concept-only pieces (public/protected/static, null, image).

Packages: a file declares package name; its top-level symbols are visible to files of the same package and to files that import name. Files without a package line are visible everywhere. The builtin modules http, json, os and path should be imported as well.

Statements are newline terminated (a ; is optional). A binary operator that starts a new line begins a new statement, so put operators at the end of the line when wrapping expressions.

Development

cd vscode-novus
npm install
npm run compile      # or: npm run watch
npm test             # parser / analyzer smoke tests against test/*.nv

Open the vscode-novus folder in VS Code and press F5 to launch an Extension Development Host with the extension loaded (it opens the repository's test/ folder). To install it permanently, build a .vsix with npm run package and use Extensions: Install from VSIX….

Project layout:

vscode-novus/
├─ package.json                  extension manifest (language, grammar, commands, settings)
├─ language-configuration.json   brackets, comments, indentation
├─ syntaxes/novus.tmLanguage.json TextMate grammar
├─ snippets/novus.json
└─ src/
   ├─ extension.ts               VS Code client + run command
   └─ server/
      ├─ lexer.ts / parser.ts / ast.ts   Novus front end (TypeScript port + concept syntax)
      ├─ analyzer.ts             scopes, symbols, type inference, diagnostics
      ├─ builtins.ts             keywords, primitive types, concept std-lib (http, json, path)
      ├─ completion.ts / features.ts     LSP providers
      ├─ formatter.ts            token based formatter
      └─ server.ts               LSP wiring