An Extensional Characterization of Lambda-Lifting and Lambda-Dropping

Abstract

Lambda-lifting and lambda-dropping respectively transform a block-structured
functional program into recursive equations and vice versa.
Lambda-lifting was developed in the early 80's, whereas lambda-dropping
is more recent. Both are split into an analysis and a transformation.
Published work, however, has only concentrated on the analysis parts.
We focus here on the transformation parts and more precisely on their
correctness, which appears never to have been proven. To this end, we
define extensional versions of lambda-lifting and lambda-dropping and
establish their correctness with respect to a least fixed-point semantics.