`@` alias to `this` with Sweet.js

at.sjs

/**
	Sweet.js version: 0.7.2

	`this` nickname `@`
	
	Expected:
		@ -> this
		@something -> this.something

	example:
	function hello (tag) {
		var element = @document.querySelectorAll(tag);
		console.log(element, @);
		Object.prototype.toString.call(@, 5);
		return @;
	}
*/
macro @ {
	rule { ; } => { this; }
	rule { , } => { this, }
	rule { $exp } => { this.$exp }
	rule { } => { this }
}

To have support for @[name] syntax from CoffeeScript, a following rule can be added before rule { $exp } => { this.$exp }.

rule { [$exp:expr] } => { this[$exp] }

Not sure entirely why last rule doesn't work in that particular case.