------------------------------------
 Guard.js - JavaScript API validation library
 ------------------------------------

 About:
   Guard.js is a library that helps validating API calls in your project
   This is useful for authors of JavaScript libraries, not end-users

 Usage:
   // Your library code
   function myLibraryFunction(sName, fHandler, bDirection, oArguments) {
       // Validate API arguments
       Guard(arguments, [
           ["name",      String],               // 'name' is required, must be string
           ["handler",   Function],             // 'handler' is required, must be function
           ["direction", Boolean, true, true],  // 'direction' is optional, if passed must be boolean or null
           ["arguments", Guard.Arguments, true] // 'arguments' is optional, if passed must be JS arguments object
       ]);

       // Execute your library code here
       return "the output of myLibraryFunction";
   };

   // User code
   >>> myLibraryFunction()
   >>> [Exception... Missing 1st required argument "name" in "myLibraryFunction" function call]

   >>> myLibraryFunction("test", true)
   >>> [Exception... Incompatible type of 2nd argument "handler" in "myLibraryFunction" function call. Expected "Function", got "Boolean"]

   >>> myLibraryFunction("test", null)
   >>> [Exception... null is not allowed value of 2nd argument "handler" in "myLibraryFunction" function call]

   >>> myLibraryFunction("test", function(){}, undefined)
   >>> [Exception... Incompatible type of 3rd argument "direction" in "myLibraryFunction" function call. Expected "Boolean", got "undefined"]

   >>> myLibraryFunction("test", new Function)
   >>> the output of myLibraryFunction

   >>> (function(){return myLibraryFunction("test", new Function, true, arguments)})()
   >>> the output of myLibraryFunction

 Data types support:
   Primitive types
     - String
     - Number
     - Boolean
     - Object
   Complex Types
     - Array
     - Function
     - Date
     - RegExp
   Special Types
     - Guard.Arguments (to designate JavaScript function arguments type)
   User-defined types
     - any custom types supported

 Supplementary APIs:

   /*Boolean*/ Guard.instanceOf(/*Variant*/ value, /*Function*/ type)

   >>> Guard.instanceOf([], Array)
   >>> true

   >>> Guard.instanceOf("1", String)
   >>> true

   >>> Guard.instanceOf("2", Number)
   >>> false

   /*Function*/ Guard.typeOf(/*Variant*/ value)

   >>> Guard.typeOf(1)
   >>> Number()

   >>> Guard.typeOf(function(){})
   >>> Function()