Eugene E. McDonnell

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Current implementations of APL give one as the result of zero divided by zero. This paper gives the reasons for proposing that this quotient be changed to zero. Two conventions introduced by K. E. Iverson [1] for the exposition of mathematical topics are used here.
This paper proposes a notation to be used for the greatest common divisor (gcd) and least common multiple (1cm) functions in APL. The notation proposed is that in use for the logical or and and functions: @@@@ for gcd and Λ for lcm. For this reason, special attention is paid to the cases of gcd and lcm for the arguments 0 and 1. Also, because we wish(More)
This paper gives some of the history of the early implementations of APL, and concentrates on the system aspects of these implementations, paying special attention to the evolution of the workspace concept, the time-sharing scheduling strategy, and the handling of the terminal. It contrasts the development of APL with the development of other time-sharing(More)
This paper is a progress report on work undertaken to include tree data structures by means of the boxed data type available in J. Methods for displaying these boxed arrays as trees are shown. This work is part of a larger effort to provide a comprehensive set of facilities in J for working with tree structures. The facilities described were at first(More)
This paper describes a series of functions for performing Conway's game of Life [Ga70] in APL, beginning with versions that go back to the early 1970's. The paper doesn't deal with the game itself, but rather with the expressive power of various approaches, and particularly with the increased expressiveness found in some of the new operator extensions to(More)
Without this extension, writers of APL applications requiring complex numbers have to simulate them by various devices which make them awkward to work with. Generally speaking, existing applications are not affected by this change. The potential differences are relatively minor and are local to just a few primitive functions. Those functions which would(More)
A reception was held at the Prime Art Gallery in downtown Toronto on the evening before the official opening of the meeting. I didn't get a count of the number of people attending, but it was big, overflowing the gallery premises so that a number of us stood on the sidewalk in front of the door, despite a slight drizzle. Among the many people I recognized(More)