Inline `Object.keys` (seems slower with Firefox)

keys.macro.sjs

let keys = macro {
	rule infix { Object. | () } => { Object.keys() }
	rule infix { Object. | ($object:expr) } => {
		(function (object) {
			if (typeof obj !== 'object' && (typeof obj !== 'function' || obj === null)) {
			  throw new TypeError('Object.keys called on non-object');
			}
		
			var keys = [], proto = object.__proto__;

			object.__proto__ = null;

			for (var key in object) {
				keys.push(key);
			}

			object.__proto__ = proto;

			return keys;
		}($object))
	}
	rule { $rest ... } => { keys $rest ... }
}

export keys;