 <unk> programming languages describe systems of operations on data streams , and the connections between the <unk> of some operations and the inputs of others . These languages can be convenient for describing repetitive data processing tasks , in which the same <unk> @-@ connected collection of operations is applied to many data items . They can be executed as a parallel algorithm in which each operation is performed by a parallel process as soon as another set of inputs becomes available to it . 
