// a parameterized interface
interface vector_if();
	parameter data_width = 4;
	
	logic	[data_width-1:0]	in;
	logic	[data_width-1:0]	out;
	
	modport pt (
		input in,
		output out
	);
endinterface

// a module performing the operation without interfaces
module op_m #(
	parameter io_width = 2
)(
	input [io_width-1:0] in,
	output [io_width-1:0] out
);
	genvar i;
	generate
	for(i = 0; i < io_width; i++) begin : op_loop
		assign out[i] = in[i];
	end
	endgenerate
	
endmodule

// a wrapper module with interfaces
module op_wrapper #(
	parameter io_width = 2
)(
	vector_if.pt io
);
	op_m #(.io_width(io_width))
	op_inst(.in(io.in), .out(io.out));
endmodule

// test module instantiating the above module and interface
module if_test(
	input	[width-1:0]	in,
	output	[width-1:0]	out
);
	localparam width = 8;
	// create interface with default parameter overriden
	vector_if #(.data_width(width)) vec_if();
	// connect interface nodes
	assign vec_if.in = in;
	assign out = vec_if.out;
	// instantiate module with default parameter overriden
	op_wrapper #(.io_width(width)) op_wrap_inst(.io(vec_if.pt));
endmodule