(fn-name f)
  f: a fn or an rfn
  returns a sym or #n

Returns a function's name.

For a GameLisp function, this is the symbol assigned using the &name flag in the fn special form, or #n if that flag was absent. A &name flag is automatically generated by macros like defn and let-fn.

This function is normally used for debugging. For example, stack-trace uses fn-name to print the name of each call-stack entry.