Summary: J. Functional Programming 1 (1): 1--000, January 1993 c
fl Cambridge University Press 1
The Call­By­Need Lambda Calculus
Zena M. Ariola y
Computer & Information Science Department
University of Oregon
Eugene, Oregon
Matthias Felleisen z
Department of Computer Science
Rice University
Houston, Texas
Abstract
Plotkin [Theor. Comp. Sci. 1975] showed that the lambda calculus is a good model of the
evaluation process for call­by­name functional programs. Reducing programs to constants
or lambda abstractions according to the leftmost­outermost strategy exactly mirrors exe­
cution on an abstract machine like Landin's SECD machine. The machine­based evaluator
returns a constant or the token closure if and only if the standard reduction sequence
starting at the same program will end in the same constant or in some lambda abstraction.
However, the calculus does not capture the sharing of the evaluation of arguments that
lazy implementations use to speed up the execution. More precisely, a lazy implementation

Source: Ariola, Zena M. - Department of Computer and Information Science, University of Oregon
Northeastern University, College of Computer Science, Programming Languages Team

Collections: Computer Technologies and Information Sciences