class Controller

def on(event, &block)

Register an event handler which may be triggered when an event is fired.

def on(event, &block)
	@events[event] << block
end

def fire(event, *args)

Fire an event which calls all registered event handlers in the order they were defined. The first argument is used to #instance_eval any handlers.

def fire(event, *args)
	return false unless @events.key?(event)
	
	handled = false
	
	scope = args.shift
	
	@events[event].each do |handler|
		handled = true

		if scope
			scope.instance_exec(*args, &handler)
		else
			handler.call
		end
	end
	
	return handled
end

def try(*arguments)

Try executing a given block of code and fire appropriate events.

The sequence of events (registered via #on) are as follows: [+:prepare+] Fired before the block is executed. May call #abort! to cancel execution. [+:success+] Fired after the block of code has executed without raising an exception. [+:failure+] Fired if an exception is thrown during normal execution. [+:finish+] Fired at the end of execution regardless of failure.

If #abort! has been called in the past, this function returns immediately.

def try(*arguments)
	return if @aborted
	
	begin
		catch(abort_name) do
			fire(:prepare, *arguments)
			
			yield
			
			fire(:success, *arguments)
		end
	rescue Exception => exception
		# Propagage the exception unless it was handled in some specific way.
		raise unless fire(:failure, *arguments, exception)
	ensure
		fire(:finish, *arguments)
	end
end

def abort!(persistent = false)

Abort the current event handler. Aborting an event handler persistently implies that in the future it will still be aborted; thus calling #try will have no effect.

def abort!(persistent = false)
	@aborted = true if persistent
	
	throw abort_name
end

def abort_name

The name used for throwing abortions.

def abort_name
	("abort_" + self.class.name).downcase.to_sym
end