Input and output declarations

The effect of the INPUT declaration is to make an assignment from the actual parameters to the corresponding formal parameters. Thus, in instance ``bit0'', the declaration

        INPUT carry_in, clear : boolean;

has the effect of assigning

        bit0.carry_in := carry[0];
        bit0.clear := clear;

Similarly, the effect of the OUTPUT declaration is to make an assignment from the formal parameters to the corresponding actual parameters. Thus, in instance ``bit0'', the declaration

          OUTPUT bit_out, carry_out : boolean;

has the effect of assigning

        count[0] := bit0.bit_out;
        carry[1] := bit0.carry_out;