Fast determination of subtype relationship in a single inheritance type hierarchy.

摘要

In a rule-based programming language which supports type inheritence, a method of subtype determination uses Huffman coding. Each object to be evaluated for subtype determinating in the type hierarchy is provided with a corresponding unique binary number, a pattern and a mask; each binary number contains information identifying ancestors in the hierarchy; the mask contains information as to the significant number of bits in the binary. A bit wise AND operation of the binary of the first object is performed with the mask of the second object to obtain a result which is compared with the binary of the Second object to determine the type/subtype of the second object. <IMAGE>