On 17/09/2008, at 5:48 AM, Frank Mittelbach wrote:

> \tlp_set:Nn\l_quark_test_tlp{#1}
> \if_meaning:NN \l_quark_test_tlp #1 ...
>
> assuming that #1 has picked up a token which may or may not be a quark
>
> is that what you are looking for?

Ha, so simple. Thanks.
And if it's *not* a quark, you're still not going to want to expand it  
(fully)!

Will