Lazy vs. Strict

Philip Wadler, University of Glasgow

To a first approximation, lazy languages are modelled by Church's call-by-name lambda calculus, while strict languages are modelled by Plotkin's call-by-value lambda calculus. The former is a good denotional model, while the latter is not; and the latter is a good operational model, while the former is not.

To improve the situation one must devise less simple but more accurate models. The construction of such models is remarkably recent, and they turn out to be surprisingly similar.

.

Last updated by sblp96@dcc.ufmg.br at Thu May 16 1996