How to define a rule parser with an empty attribute?

[akrzemi1]

The docs do not state it clearly, how I can define a rule parser with an empty attribute (e.g., when I need a parser for skipping comments). Neither in the tutorial, nor in the reference section?

I am guessing that I need to skip the second template parameter. Is that right?

[tzlaine]

Yes, that's right. I'll add this to the docs in a way that's more clear. I swear it used to say that....