Friday 15 July 2016

A fairytale found on Stack Overflow


Somewhere on the Internets there is that little fairy tale about a little princess*, written in the
language of dreams, i.e. Javascript:

  function princess() {

      var adventures = [];

      function princeCharming() { /* ... */ }
  
      var unicorn = { /* ... */ },
          dragons = [ /* ... */ ],
          squirrel = "Hello!";

      return {
          story: function() {
              return adventures[adventures.length - 1];
          }
      };
  }

  var littleGirl = princess();
  littleGirl.story();

Can you read it? If not, there is this attempt of translation by Patrick M:
"...the princess() function is a complex scope containing private data. Outside the function, the private data can't be seen or accessed. The princess keeps the unicorns, dragons, adventures etc. in her imagination (private data) and the grown-ups can't see them for themselves. BUT the princess's imagination is captured in the closure for the story() function, which is the only interface the littleGirl instance exposes into the world of magic. – Patrick M Feb 28 '13 at 7:49"  
Still an alien language? Learn some Javascript closures, would you? And then a story unveils:
Domenichino [Public domain], via Wikimedia Commons
Once upon a time, there was a princess, her world was full of adventures: dragons, unicorns, talking squirrels (Narnia?). But because in this world she was only a little girl, she only could tell stories about her adventures. And nobody would believe her, because she couldn't take anybody into her magical land (due to a curse of an old, ugly witch called Ecma). So the princess was both happy and sad, because she couldn't share her adventures with anyone. An that's the tragic of sorcery, you have always to pay a price for it...
Now that you are in the know, did you notice, that the princess doesn't tell anyone about Prince Charming?

--
* source: https://stackoverflow.com/questions/111102/how-do-javascript-closures-work/6472397#6472397

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