What's the right way to test if regex.match() hits or not?

[Russell Lewis]

I'm trying to use regex.match() for a tokenizer.  So I want to compare 
my input to a bunch of different regex'es, expecting one to hit and the 
rest not to.

Problem is, I can't seem to figure out the "right" way to ask if a hit 
occurred.  My code is roughly this:

BEGIN CODE
while(input.length > 0)
{
	auto r1 = regex("^...something nasty...");
	auto r2 = regex("^...something worse...");

	auto tmp = match(input, r1);
	if(<check r1 here>)
	{
		ReportTokenType1(tmp.hit())
		input = tmp.post();
		continue;
	}

	... and so on ...
}
END CODE

What do I put inside the if()?

P.S. Does anybody know why dmd complains "cannot evaluate at compile 
time" when I set those regex objects to "static invariant" so I'm not 
rebuilding them with every pass?