Tree-walking ECMAScript interpreter built on ecma-syntax-cat. v0.3.0 added accessor-property support at the engine level (`Object::with_accessor`, getter/setter dispatch on read/write). v0.3.1 picks up ecma-parse-cat 0.2 so the same dispatch path now also fires for accessor / shorthand-method object-literal syntax (`{ get x() {} }` / `{ set x(v) {} }` / `{ foo() {} }`) in user-provided JS source -- the engine already handled those AST variants in 0.3.0, only the parser was holding it back.