Q'Nial: A portable interpreter for the nested interactive array language, Nial

The Q'Nial interpreter combines ideas from APL and Lisp implementations to provide a rich programming environment that supports several paradigms of programming. The interpreter is structured to reflect the division of Nial semantics into levels corresponding to zero‐, first‐and second‐order objects. The paper describes the design of the interpreter, discusses constraints imposed by the desire to achieve portability and comments on what has been learned in building an interpreter in this style.