primitive recursive attribute

Presents the abstraction on algorithms and primitive recursion constructor,aiming to reinforce the high reusability and extensibility of generic algorithms.

将对递归算法进行抽象,构造原始递归构造子,使得一般的泛型算法都可以通过该算子来构造,从而加强泛型算法的可复用型与可扩展性。