High-level Programming Language for Interactive Lisp-like Languages

Abstract

The language LISP 1.5 is neither easy to write nor to read. In the McCarthy etal. definitive manual on LISP 1.5 a higher level language, MLISP, is used From the early 1960's various people have proposed higher level languages for LISP. Two types oflanguages may be distinguished: those based on a LISP programming style, but more readable, and those based on an Algol style. The language PLISP is a language in which it is attempted to reconcile the two approaches to high level languages for LISP. The notation is based on the Algolstyle languages but is brief and adapted for terminal use. PLISP allows full access to all the LISP features in a consistent notation. In addition there are features that will appeal to the mathematically mature programmer: full infix notation for not only the assignment, arithmetic, and logical operators, but also for lists, sets, and chained relations. PLISP also has a consistent notation for the first order predicate logic and a variety of ways in which functions may be defined. Top-down program development is facilitated by the use ofan assertional language FEA which can be translated to PLISP for test-data generation. Furthermore a definite notation for function stubs is made available - the stubs yield values although the functions called have not been defined at that stage.