class.sjs

class.sjs

// Class Macro with Support for Inheritance
// ========================================

macro class {
  rule { $className($cparam:ident (,) ...) { $cbody } } => {
    function $className($cparam (,) ...) {
      if (!(this instanceof $className)) {
        return new $className($cparam (,) ...);
      }
      $cbody ...
    }
  }
  rule { $className($cparam:ident (,) ...) extends $superClass:ident (,) ... { $cbody ... } } => {
    function $className($cparam (,) ...) {
      if (!(this instanceof $className)) {
        return new $className($cparam (,) ...);
      }
      $($superClass.call(this);) ...
      $cbody ...
    }
    (function(inherits) {
      $(inherits($className, $superClass);) ...
    }(require('util').inherits));
  }
}

// Example: Extending EventEmitter
// -------------------------------

var EventEmitter = require('events').EventEmitter;

class Person(name) extends EventEmitter {
  Object.defineProperty(this, 'name', {
    value: name
  });
}

Person.prototype.say = function(something) {
  this.emit('say', this.name + ' said, "' + something + '"');
};

var bob = new Person('Bob');
bob.on('say', function(something) { console.log(something); });
bob.say('Hello world!');

/*

$ sjs -r --format-indent=2 class.sjs

// Example: Extending EventEmitter
// -------------------------------
var EventEmitter = require('events').EventEmitter;
function Person(name) {
  if (!(this instanceof Person)) {
    return new Person(name);
  }
  EventEmitter.call(this);
  Object.defineProperty(this, 'name', { value: name });
}
(function (inherits) {
  inherits(Person, EventEmitter);
}(require('util').inherits));
Person.prototype.say = function (something) {
  this.emit('say', this.name + ' said, "' + something + '"');
};
var bob = new Person('Bob');
bob.on('say', function (something) {
  console.log(something);
});
bob.say('Hello world!');

$ sjs -r --format-indent=2 class.sjs | node
Bob said, "Hello world!"

*/