my $el;
	while ($el = pop @els) {
		# Body of loop
	}

##</code><code>##

	sub while (BOOL $condition, &closure) {...}

	sub if (BOOL $condition, &closure) {...}

##</code><code>##

	if condition(), &call_me;

##</code><code>##

	&debug := { if BEGIN{$debug}, &^action };

	# and later...

	debug { print "here" }