Apart from APL, he also found beauty in nature, opera, the music of Tom Waits, the literature of James Joyce,[3] the poetry of W. B. Yeats.

Between 1977 and 1978 he worked with the European Space Agency in Madrid, Spain as a programmer for the International Ultraviolet Explorer project.

Examples of using direct definition are found in the 1979 Turing Award Lecture[8] and in books and application papers.

Of these, the "alternative APL function definition" of Bunda in 1987[19] came closest to current facilities, but is flawed in conflicts with existing symbols and in error handling which would have caused practical difficulties, and was never implemented.

[13] In 1996, Scholes invented direct functions or dfns (pronounced "dee funs"), a major distinguishing advance of early 21st century APL over prior versions.

The ideas originated in 1989 when he read a special issue of The Computer Journal on functional programming.

[25] He then proceeded to study functional programming and became strongly motivated ("sick with desire", like Yeats) to bring these ideas to APL.

[28] They also play a key role in efforts to exploit the computational capabilities of a GPU (graphics processing unit).

Applying the function derived from Q3 to the same argument multiple times gives different results because the pivots are chosen at random.

[31] However, unlike the pidgin ALGOL program in Figure 3.7, Q and Q3 are executable, and the partial order used in the sorting is an operand, the (×-) the examples above.