Cub for VS Code

Language support for Cub — a small language in the C family that tells you what went wrong.

Syntax highlighting, formatting, and errors underlined as you type, with the compiler's own suggestions carried into the hover.

Requirements

This extension drives the Cub compiler, so you need cubc on your PATH:

git clone https://github.com/Seth-dse/cub.git
cd cub
make
make install          # or: make install PREFIX=$HOME/.local

If cubc lives somewhere else, point the extension at it:

{ "cub.compilerPath": "/full/path/to/cubc" }

Without the compiler you still get highlighting and snippets; formatting and error checking need it.

What you get

Errors as you type

cubc --check runs in the background and its output becomes squiggles. The compiler's help: line comes along with the message, so hovering a mistake tells you how to fix it:

count was declared with let, so it never changes

help: declare it with var count = ...; if it needs to change

Misspell a name and it suggests the right one. Forget a struct field and it names the one you forgot. Skip a return on one branch and it finds the branch — before the program ever runs.

Highlighting

Keywords, types, every built-in, classes, self and super, import and the module names, /// doc comments, numbers, escapes, and nested block comments. Expressions inside interpolated text are highlighted as code, so {count + 1} in "you have {count + 1} left" reads as an expression rather than as string contents.

Formatting

Format Document (Shift+Alt+F) runs cubc fmt. The formatter only ever changes horizontal whitespace — it cannot alter what your program does.

Format on save:

{
  "[cub]": {
    "editor.formatOnSave": true,
    "editor.defaultFormatter": "Sethttech.cb"
  }
}

A file icon

.cb files get a cub in the explorer. VS Code shows it when your active file icon theme has nothing of its own for the extension, which is the case for the built-in Seti theme. Some themes — Material Icon Theme among them — supply a fallback for every unknown extension, and those win; with one of those you will see the theme's generic icon instead.

Snippets

main, fn, void, fnm, static, if, ife, ifx, for, fore, while, struct, enum, class, classx, classmain, map, import, importf, ///, print, printv.

Commands

Command Palette, or right-click in a .cb file:

Command	What it does
Cub: Run File	saves, then runs it in a terminal
Cub: Check File for Errors	checks now, rather than waiting
Cub: Show Generated C	opens the standalone C your program compiles to

Settings

Setting	Default	Meaning
`cub.compilerPath`	`cubc`	where to find the compiler
`cub.checkOnType`	`true`	underline errors while typing, not only on save
`cub.checkDelay`	`400`	milliseconds of quiet before checking

A taste of the language

class Animal {
    name: string;

    void init(name: string) {
        self.name = name;
    }

    string speak(){
        return "{self.name} makes a sound";
    }
}

class Dog extends Animal {
    void init(name: string) { super.init(name); }
    string speak(){ return "{self.name} says woof"; }
}

void main() {
    let pets: [Animal] = [Animal("Generic"), Dog("Rex")];
    for pet in pets {
        print(pet.speak());      // each one keeps its own voice
    }
}

Build errors in the Problems panel

A cubc problem matcher ships with the extension. In .vscode/tasks.json:

{
  "version": "2.0.0",
  "tasks": [
    {
      "label": "cub: build",
      "type": "shell",
      "command": "cubc ${file}",
      "problemMatcher": "$cubc",
      "group": { "kind": "build", "isDefault": true }
    }
  ]
}

License

MIT

Cub Language

Sethttech