dplyukhin

import Data.List

type Program = [SExp]

-- Note that we are using Strings in our compiler to denote Lisp *symbols*;
-- The Lisp we are writing has no string primitives of its own.
data SExp = Literal Integer  -- e.g. 5, 42
          | Symbol String    -- e.g. x, first, lambda, -
          | SExp [SExp]      -- e.g. (+ (* 3 2) 4), (define fact (lambda n (fact (- n 1))))

dplyukhin

// object_1.foo === 'bar'
// object_1['foo'] === 'bar'
var object_1 = {
    foo: 'bar'
}

// object_2 uses object_1 as its *prototype* - it inherits the properties but they are not its own
// object_2.hasOwnProperty('foo') === false
// object_2.foo === 'bar'
var object_2 = Object.create(object_1);

dplyukhin

class EventEmitter:
    """Create listeners on an object"""
    
    def __init__(self):
        self._events = {}
        
    def on(self, event, callback):
        """Execute callback when event is emitted. Returns an id for deletion.
        
        event {String}