input.js

import { odd as local_odd } from "./b";

export var counter = 0;

export default function even(n) {
    console.log("even has run %s times", counter++);
    return n === 0 || local_odd(n - 1);
}

output.js

System.register("tests/others/a", function($import_bind, $export_bind, $export_push) {
    return {
        deps: [ "./b" ],
        execute: function() {
            "use strict";
            var local_odd, counter;

            // m.setup(...dep_configs, exports)
            $import_bind("odd", function($cur){ local_odd = $cur });
            $export_bind("default", function(){ return even });
            $export_bind("counter", function(){ return counter });

            /* begin source body */

            $export_push("counter", counter = 0); // push to importers, return argument[1]

            function even(n) {
                console.log("even has run %s times", $export_push("counter", counter++));
                return n === 0 || local_odd(n - 1);
            }
        }
    };
});

// This is what the push operation would sort-of look like
meta.execute.push = function(name, pass_through) {
    var newVal = my.exports[name](); // fetch the value to push from the export_binding

    // push newVal out to subscribers of `name`

    return pass_through;
};