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Let's say you want to implement TypeScript with macros:

function foo(str: string) {
    return str.toUpperCase()
    //        ^
    // want to provide completion here
}

So we define the function macro:

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var random = function(seed) { /* ... */ } 
let m = macro { 
  rule {()} => { 
    var n = random(42); // ... 
  } 
}

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macro = {
	rule { > { $body ... } } => { function foo() { $body ...} }
}

=> { return 42; }

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let let = macro {
    rule { async $vars  ... = $fname ... ($params ...); $rest ...} => {
        $fname ... ($params ..., function (err, $vars ...) { 
            if (err) throw err;
            $rest ... 
        })
    }
}

var buffer = new Buffer(1024);

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let function = macro {
	case { _ * $id ($args ...) { $body ... } } => {
		var body = #{ $body ... };
		var isAwaitGenerator = false;
		for (var i = 0; i < body.length; i++) {
			if (body[i].token.type === parser.Token.Identifier &&
				body[i].token.value === 'await') {
				var expr = getExpr(body.slice(i));
				if (expr.success) {
					isAwaitGenerator = true;

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letstx $name ... = [name1, name2, name3];
letstx $type ... ... = [[type1, type2], [type3, type4]]

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// the web is crazy
// http://stackoverflow.com/questions/736513/how-do-i-parse-a-url-into-hostname-and-path-in-javascript
function getLocation(href) {
    var location = document.createElement("a");
    location.href = href;
    // IE doesn't populate all link properties when setting .href with a relative URL,
    // however .href will return an absolute URL which then can be used on itself
    // to populate these additional fields.
    if (location.host == "") {
      location.href = location.href;

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operator >>= left 1 = (left, right) => { 
  return #`${left}.then(${right})`;
} 
fetch('/foo.json') >>= resp => { return resp.json() } 
                   >>= json => { return processJson(json) }

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fetch("/foo.json").then(resp => { 
  return resp.json(); 
}).then(json => { 
  return processJson(json); 
});

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// foo.js
'lang sweet.js';
export syntax m = // ... 

// main.js
'lang sweet.js'; 
import { m } from './foo'; 
m // ...