Programming J.J. Homing Languages Editor The SL5 Procedure Mechanism

This paper describes an integrated procedure mechanism that permits procedures to be used as recursive functions or as coroutines. This integration is accomplished by treating procedures and their activation records (called environments) as data objects and by decomposing procedure invocation into three separate components at the source-language l vel. In addition, argument binding is under the control of the programmer, permitting the definition of various methods of argument ransmission in the source language itself. The resulting procedure mechanism, which is part of the SL5 programming language, is well suited to goal-oriented problems and to other problems that are more readily programmed by using coroutines. Several examples are given. Key Words and Phrases: procedures, coroutines, programming languages, interpreters, SNOBOL4, backtrackin