| dc.description.abstract | Many loops can be more easily understood  and manipulated if they are viewed as being  built up out of operations on sequences of  values. A notation is introduced which makes  this viewpoint explicit. Using it, loops can be  represented as compositions of functions  operating on sequences of values. A library of  standard sequence functions is provided  along with facilities for defining additional  ones. The notation is not intended to be  applicable to every kind of loop. Rather, it has  been simplified wherever possible so that  straightforward loops can be represented  extremely easily. The expressional form of the  notation makes it possible to construct and  modify such loops rapidly and accurately. The  implementation of the notation does not  actually use sequences but rather compiles  loop expressions into iterative loop code. As a  result, using the notation leads to no  reduction in run time efficiency. | en_US |