I would like to see the output of printf() when RULES is set for debugging purposes. Bug or feature? I couldn't find anything in the manual about this behavior. Can I enable the output myself?

Code
function run() 
{
	set(RULES);
	printf("\nHello.");
}


If I click Train, I see nothing. If I click Test, I see:

Hello.
Hello.
Hello.
Hello.
...