OPL-I An Open Ended Programming System Within CTSS

Abstract

OPL-1, an incremental programming system presently operating with CTSS, permits the user to augment both his program and his data base during widely separated successive sessions at his terminal. Facilities are provided which make it possible for the user to operate on his already established data base both by means of built-in operators and in terms of operators (functions) which the user has previously defined in the language of the system. Underlying the system is a powerful list processing scheme embedded in FORTRAN (SLIP). The machinery of this fundamental language drives the system and is also largely available to the user. The data base generated by the user is therefore a set of list structures (trees), and most of the operators available to him are list processing operators. Data structures with considerably complex inter-relational properties may therefore be treated quite directly.