In a previous paper, Halstead's theory was applied to first generation APL.
Those implementations only support simple arrays (APL/SA). In this paper w
e extend the application of Halstead's theory to second generation APL; the
main difference being that those implementations support arrays of arrays
or nested arrays (APL/NA). In both investigations, Halstead's theory had to
be adjusted in order to account for the fact that in APL operations may be
functions or operators. It is shown that the language level increases from
3.07 for APL/SA to 3.62 for APL/NA This means that language efficiency of
APL versus assembler raises from about 12 for APL/SA to nearly 17 for APL/N
A.