webidl-bindgen.mbt

WebIDL to MoonBit binding generator.

Features

• Parse WebIDL files and generate MoonBit FFI bindings
• Fetch WebIDL directly from W3C specs via @webref/idl
• Generate type-safe bindings for interfaces, dictionaries, enums, and typedefs
• Support for all 300+ W3C/WHATWG specifications

Installation

npm install -g webidl-bindgen.mbt
# or
bun add -g webidl-bindgen.mbt

Usage

Generate bindings for all W3C specs

webidl-bindgen.mbt --all --per-spec -o ./src/

Single spec

webidl-bindgen.mbt --spec html -o ./src/

Multiple specs

webidl-bindgen.mbt --specs html,dom,cssom,fetch -o ./src/

From local WebIDL file

webidl-bindgen.mbt --input canvas2d.webidl -o ./src/

Options

-i, --input <file>      Input WebIDL file
-s, --spec <name>       Single spec from @webref/idl (e.g., html)
    --specs <list>      Comma-separated list of specs
-a, --all               Load all specs from @webref/idl
    --per-spec          Output each spec to separate file (with --all or --specs)
-o, --output <dir>      Output directory (default: ./)
-h, --help              Show this help message

Note: --input, --spec, --specs, and --all are mutually exclusive.

Generated Code

The generator produces MoonBit code with:

• pub type declarations for interfaces and callback interfaces
• pub extern "js" fn for methods and attributes
• pub enum for WebIDL enums with to_string/from_string helpers
• pub struct for dictionaries with default() and to_js() methods
• pub type aliases for typedefs

Example Output

/// HTMLElement interface
pub type HTMLElement

/// Get the inner text
pub extern "js" fn HTMLElement::inner_text(self : HTMLElement) -> String =
  #| (self) => self.innerText

/// Set the inner text
pub extern "js" fn HTMLElement::set_inner_text(self : HTMLElement, value : String) -> Unit =
  #| (self, value) => { self.innerText = value }

Dependencies

• webidl2 - WebIDL parser
• @webref/idl - W3C spec IDL collection

Known Limitations

Currently not supported (planned):

• Constructor generation (new Blob() etc.)
• Inheritance (parent interface methods)
• Static methods (URL.createObjectURL())
• Special getter/setter/deleter (indexed access)

License

MIT