An input allows the consumption of the specified input signal instance. The consumption of the input signal makes the information conveyed by the signal available to the process. The variables associated with the input are assigned the values conveyed by the consumed signal.
The values will be assigned to the variables from left to right. If there is no variable associated with the input for a sort specified in the signal, the value of this sort is discarded. If there is no value associated with a sort specified in the signal, the corresponding variable becomes "undefined".