Can a Verilog function take a boolean argument?

I've got a Verilog function that I'd like to behave slightly differently depending on the value of a boolean argument, an argument whose value can be either (true) or (false). I tried:

  module sid ();


function integer execOp;      input integer left;      input integer right;      input boolean add;    begin      execOp = add ? left + right : left * right;    end  endfunction

endmodule  

Then when I use Icarus to simulate it I get:

  D:\Hf\Verilog\Unpacked\Common>\Icarus\bin\iverilog -g2009 -o sid.out sid.sv  sid.sv:6: syntax error  sid.sv:3: error: Syntax error defining function.


D:\Hf\Verilog\Unpacked\Common>  

Line 6 is the line where I declare variable (add). Is there a way to pass a boolean argument to a function, or am I going to have to declare an (enum) that has values (true) and (false)?