x2c - C with batteries

This VS Code extension provides the TextMate grammar and language configuration for x2c source files (.x, .xc, .xh, .x2c, and .xmacro) and compile-time Lisp files (.xlisp).

It highlights x2c list, array, map, string, Symbol, and SymbolSet literals, including data-first Array and Map contents and their runtime unquotes; pattern variables; runtime unquote and List splice forms; protocols; macros; decorators; with blocks; List destructuring; imports; delegate fields; Self method types; embedded and standalone compile-time Lisp; and the C-compatible syntax used by the language.

This is a syntax-only extension. It does not install or run the x2c compiler, execute workspace code, collect telemetry, or make network requests.

Installation

Find x2c - C with batteries by x2c in the VS Code Extensions view, or install a packaged VSIX with Extensions: Install from VSIX.

Distinct x2c colors

The extension contributes scopes but does not override the active theme. To use the colors shown below, copy either the dark or light setting into VS Code's settings.json.

Dark backgrounds:

"editor.tokenColorCustomizations": {
  "textMateRules": [
    {
      "scope": [
        "keyword.control.in.x2c",
        "keyword.control.try.x2c",
        "keyword.control.catch.x2c",
        "keyword.control.finally.x2c",
        "keyword.control.defer.x2c",
        "keyword.control.raise.x2c",
        "keyword.control.match.x2c",
        "storage.modifier.delegate.x2c",
        "storage.modifier.threaded.x2c",
        "keyword.control.import.x2c",
        "keyword.control.with.x2c",
        "keyword.declaration.protocol.x2c",
        "keyword.control.foreach.x2c",
        "keyword.operator.is.x2c",
        "storage.type.self.x2c",
        "keyword.declaration.macro.x2c",
        "keyword.other.macro.using.x2c",
        "keyword.operator.arrow.x2c"
      ],
      "settings": { "foreground": "#FF4FD8", "fontStyle": "bold" }
    },
    {
      "scope": "support.type.prelude.x2c",
      "settings": { "foreground": "#29D3E2", "fontStyle": "" }
    },
    {
      "scope": [
        "storage.type.macro.result.x2c",
        "storage.type.macro.hole.x2c"
      ],
      "settings": { "foreground": "#FFB454", "fontStyle": "italic" }
    }
  ]
}

Light backgrounds:

"editor.tokenColorCustomizations": {
  "textMateRules": [
    {
      "scope": [
        "keyword.control.in.x2c",
        "keyword.control.try.x2c",
        "keyword.control.catch.x2c",
        "keyword.control.finally.x2c",
        "keyword.control.defer.x2c",
        "keyword.control.raise.x2c",
        "keyword.control.match.x2c",
        "storage.modifier.delegate.x2c",
        "storage.modifier.threaded.x2c",
        "keyword.control.import.x2c",
        "keyword.control.with.x2c",
        "keyword.declaration.protocol.x2c",
        "keyword.control.foreach.x2c",
        "keyword.operator.is.x2c",
        "storage.type.self.x2c",
        "keyword.declaration.macro.x2c",
        "keyword.other.macro.using.x2c",
        "keyword.operator.arrow.x2c"
      ],
      "settings": { "foreground": "#A626A4", "fontStyle": "bold" }
    },
    {
      "scope": "support.type.prelude.x2c",
      "settings": { "foreground": "#007C8A", "fontStyle": "" }
    },
    {
      "scope": [
        "storage.type.macro.result.x2c",
        "storage.type.macro.hole.x2c"
      ],
      "settings": { "foreground": "#A15C00", "fontStyle": "italic" }
    }
  ]
}

The syntax scopes cover in, try, catch, finally, defer, raise, match, delegate, threaded, import, with, as, protocol, associated, foreach, is not, Self, macro, keyword, using, and =>. Prelude types use support.type.prelude.x2c: Array, Atom, Block, Buffer, Bytes, Context, Error, ErrorHandler, File, Func, Iter, Lambda, Lisp, List, Logger, LogSink, Map, Mutex, Pool, Scope, Split, String, Symbol, SymbolSet, Thread, Token, Tokenizer, and Var. Macro result and hole kinds keep the storage.type.macro.result.x2c and storage.type.macro.hole.x2c scopes.

For another background, keep the scope arrays and change only the three foreground values. An empty fontStyle keeps prelude types upright. The specific keyword and modifier scopes retain their broader parent scopes, so existing theme rules continue to apply when these settings are absent.

Development

Open this directory in VS Code and press F5 to launch an Extension Development Host. Open an x2c source file and use Developer: Inspect Editor Tokens and Scopes to inspect the grammar.

The most useful scopes are:

• punctuation.definition.literal.*.x2c for literal delimiters;
• meta.literal.*.content.x2c for collection contents;
• constant.other.atom.x2c for bare data names;
• constant.other.symbol.x2c for symbols;
• variable.other.pattern.*.x2c for pattern variables; and
• variable.other.interpolation.*.x2c for runtime unquote and splice forms;
• meta.destructuring.*.x2c and variable.other.readwrite.destructuring.x2c for List destructuring;
• keyword.declaration.macro.x2c and entity.name.function.macro.x2c for macro definitions and applications; and
• meta.embedded.lisp.x2c and *.lisp.x2c for compile-time Lisp.

Standard C strings retain the standard string.quoted.double and string.quoted.single scopes for theme compatibility.

Packaging

Install the pinned development dependencies, run the scope tests, then build the VSIX:

npm ci
npm test
npm run build

The packaged VSIX is tracked with the extension source. Install it from VS Code with Extensions: Install from VSIX.

When changing the grammar, keep x2c-specific rules ahead of competing C operator, call, string, and angle-bracket rules. Add scope tests for both the x2c form and the ordinary C syntax it could be confused with.

Marketplace identity

The Marketplace publisher is x2c-lang, displayed as x2c. The extension ID is x2c-lang.x2c-syntax. Version 0.1.23 retains the Preview label.

License and support

The extension is licensed under the Apache License 2.0; its attribution notice is in NOTICE. x2c is experimental and has no support commitment. See SUPPORT.md for reporting bugs and getting help.