[Gramps-devel] How control variable can make the report displays Call Name if exists, Given Name otherwise

[setan k. <set...@ya...>]

I have tried the following control variables statement in the report generator window:
     {$n(c) $n(f)}
But it also displayed the Given Name although the Call Name existed.
What I want is to make report displays ONLY Call Name if exists, but ONLY Given Name if Call Name doesn't exist.

Thanks for advance.