ISO/IEC 13211 is designed to promote the applicability and portability of Prolog text and data among a variety of data processing systems. This part of ISO/IEC 13211 specifies: a) The representation of Prolog text, b) The syntax and constraints of the Prolog language, c) The semantic rules for interpreting Prolog text, d) The representation of input data to be processed by Prolog, e) The representation of output produced by Prolog, and f) The restrictions and limits imposed on a conforming Prolog processor.