In this article, we discuss two programming language features that hav
e value for expressibility and efficiency: nonstrictness and nondeterm
inism. Our work arose while assessing ways to enhance a currently succ
essful language, SISAL [McGraw et al. 1985]. The questions of how best
to include these features, if at all, has led not to conclusions but
to an impetus to explore the answers in an objective way. We will reta
in strictness for efficiency reasons and explore the limits it may imp
ose, and we will experiment with a carefully controlled form of nondet
erminism to assess its expressive power.