processing2-exports.js

var processing2 = (function(global) {
  var exports = {};

  exports.drawCircle = function() {
    // something
  };

  exports.setColor = function() {
    // something
  };

  exports.onMouseUpdate = function(x, y) {
    // exports.mouseX = x;
    // exports.mouseY = y;
    exports.setProperty('mouseX', x);
    exports.setProperty('mouseY', y);
  };

  // Rudimentary export system

  var allExports = [exports];
  var excludes = /^p_|setProperty|globals/;

  exports.setProperty = function(name, value) {
    allExports.forEach(function(exports) {
      exports[name] = value;
    });
  };

  exports.globals = function(exportTo) {
    // Default to global object (window?)
    if (!exportTo) { exportTo = global; }
    // Add exportTo object to allExports array
    if (allExports.indexOf(exportTo) === -1) { allExports.push(exportTo); }
    // Copy methods and properties to global object.
    Object.keys(exports).forEach(function(method) {
      if (excludes.test(method)) { return; }
      exportTo[method] = exports[method];
    });
  };

  return exports;
}(this));

usage.html

<script src="processing2.js"></script>
<script>processing2.globals();</script>

<script>
  processing2.onMouseUpdate(100, 200);
  processing2.mouseX // 100
  processing2.mouseY // 200
  mouseX // 100
  mouseY // 200
</script>