Why should I love JSON applets?

Do you want to allow others to script your apps? In other words: turn your apps into a platform the quick & easy way? And... you want them sandboxed? Then try JSON applets.

Do you want to create a simple to use declarative language and pass it around using JSON? Then try JSON applets.

Example:

Your app users send you this JSON:

[
  "form", ["my_dom_id", "post", "http://my_url.something/"], [
    "text_input", [ "dom_id_2", {lines: 1} ], [
      "Input your name here."
    ],
    "button", [ "Save" ],
    "on_click", [ "submit_form" ]
  ]
]

You then process the above into HTML and JS... using Ruby, Python, Factor, etc.

Alternatives:

• Adsafe

The Standard

The starting point is an array:

[ "print", ["hello", "world"] ]

You have to define what "print" does.

Function calls: A string followed by one or more arrays or object (ie {name: vale}).

[
   "remove" , ["my_form", "my_spouse"], ["some", "other", "args", [ 1, 2, 3 ]],
   "add"    , {right: 1, left: "2"}
]

Any string followed by another string is considered a function call without arguments:

[
   "my_func_with_no_args",
   "my_func_with_args", [ 1, 2, 3 ]
]

There are no plans for variables or methods because JSON applet because there are closer in pedigree to SQL/DSLs/POLs than to a full scripting/prog. lang.

The nodejs/npm implementation:

npm install json_applet (Currently, it's not on the npm yet.)

var Applet = require('json_applet').Applet;
var source = [
  "form", ["my_form"], [
    "text_input", [ "my_name", {lines: 1} ], [
      "Input your name here."
    ],
    "button", [], [ "Save" ],
    "on_click", [ "submit_form" ]
  ]
];

var HTML = Applet(source);

HTML.def('form', function (call_meta, args) {
  call_meta.name   // 'form'
  call_meta.prev   // the previous func call and args: [name, array1, array2, ...]
  call_meta.curr   // the current func call: ['form', array1, array2]
  call_meta.data   // an object you can use to save and pass around data to other
                   //   func calls.
  call_meta.app.run(args_array); // compile args as if it were a sub-call_meta.
  return "<form> ... </form>";
});

HTML.def_in('form', 'text_input', my_func) // "text_input" only allowed inside a "form".
HTML.def_parent('form', my_func)           // A "form" can not be inside another "form".
HTML.after_run(some_func);                 // See below: "Events".
HTML.run();                                // returns itself.
HTML.run().results                         // the results of your applet.
HTML.run().error                           // any error.

If there are any errors, they are returned from .run as:

{ error: new Error("the msg") }

Events

If you want to process your results after calling .run(), just add different callbacks using .after_run()

My_Applet.after_run(function (app) {
  var results = app.results;
  // do something...
  app.results = my_new_results;
});

My_Applet.after_run(function (app) {
  // do something...
  app.results = my_other_new_results;
});

Now, when you call .run(), the results are run through the callbacks you defined in .after_run:

My_Applet.run().results; // results are processed through the callbacks.

There are no more "events" other than after_run.

History

Formerly called: ok_slang.

A better way:

You have a client (PC, virtual machine, tablet, etc.). You want to script it using Haskell, but the machine only partys with JavaScript. How do you solve it? Make the problem more complicated... What if you have 1 billion people who all use 1 million different languages... and they all want to run code on the machine...

The Alan Kay Way: Let the client run binary code using a sandbox. Then, collect the output and present the result to the USER or to another process/VM.

The sandbox can decide how much CPU/RAM/etc the binary code can have, how much access to the screen/speakers/etc it gets, etc.

This way, you can run almost any past/present/future language on the client securely. This is of course too radical and not common (despite being Oper. Sys 101). (And no... JS ByteArray/ASM.js is not the answer. It's better than nothing, but not what AK was thinking about.)

For more on Alan Kay, go to youtube and vimeo. His 30+ min lectures are heavenly.

The End

... for now.