castSwitch

Executes one of a series of handlers based on the dynamic type of a class instance.

switchObject's dynamic type is checked for compatibility with the argument type of each

choice in turn until a match is found. When there's a match, the choice will be called with switchObject cast to that type. If the choice returns a value, castSwitch will return it.

• If one choice's return type is void and one can return a value, SwitchError will be thrown if the void handler was matched and completed execution without throwing.
• A void handler is allowed to return when all the choices' return types convert to void - in that case, castSwitch itself will return void.
• A choice's return type can be noreturn (e.g. when a handler always throws an exception).

  Throws

  If none of the choices match, a SwitchError will be thrown. SwitchError will also be thrown if one choice can return a value but a void choice was matched and completed execution.

  Parameters

  choices	A sequence of function and/or delegate handlers that each accept one argument. There can also be one choice that accepts zero arguments, which will be invoked if the switchObject is null.
  switchObject	the object against which the tests are being made.

  Returns

  The return value of the selected choice.