Abstraction.js "Lite" (live-coded at BrazilJS 2012)

abstraction-lite.js

/*
 * Abstraction.js "Lite"
 *
 * Copyright (c) 2012 "Cowboy" Ben Alman
 * Licensed under the MIT license.
 * http://benalman.com/about/license/
 */

var $elseif, $else;
var $if = function(state) {
  var nop = function() {};
  var exec = function(fn) { fn() };
  if (state) {
    $elseif = function() { return nop; };
    $else = nop;
    return exec;
  } else {
    $elseif = $if;
    $else = exec;
    return nop;
  }
};

usage.js

// Why log now when we can log later?

var console$log = function(arg) {
  return function() {
    console.log(arg);
  };
};


// Valid JavaScript

$if (true) (
  console$log("1")
)
$elseif (true) (
  console$log("shouldn't log a")
)
$else (
  console$log("shouldn't log b")
)

$if (false) (
  console$log("shouldn't log c")
)
$elseif (true) (
  console$log("2")
)
$elseif (true) (
  console$log("shouldn't log d")
)
$elseif (false) (
  console$log("shouldn't log e")
)
$else (
  console$log("shouldn't log f")
)

$if (false) (
  console$log("shouldn't log g")
)
$elseif (false) (
  console$log("shouldn't log h")
)
$else (
  console$log("3")
)

// Logs:
// 1
// 2
// 3

Also see the original, Abstraction.js.

OMG

well this completely blew my mind

@cowboy if the whole language could be written this way and macros were implemented, I think this could be awesome. JavaScript could consist of a small set of functions and really simple syntax.