`define macros usage

In reply to dave_59:

So you are suggesting the 2nd `` in I or in R has no meaning so if the macro is like this :

`define xyz(I,R)
assign abc(I).clk = R.duI_clk_x;

`xyz(1,a)

will still be :

assign abc(1).clk = a.du1_clk_x;