Is there a ViewCategories macro that I can use for a categories root file index.txt?

right now I have one that has this:

<%radio.macros.viewCategoryList ()%>

 which obviously isn’t legit,  cuz I get this when I go to it:

[Macro error: Can’t call the script because the name “viewCategoryList” hasn’t been defined.]

Is what I’m after something doable? Or better yet,  has it been done?