Intensional Equality ;=) for Continuations

Abstract:

I propose a novel language feature, intensional continuation equality,
useful in languages with or without first-class continuations, and
show how it enables truly remarkable gains in efficiency of ordinary user
programs.

Continuations, expressing ``what the program will do from now on,''
are a much-used tool of semantics, and sometimes show up as a user-accessible
programming feature. But most use of continuations is parametric,
in the sense that functions behave the same way independent of their
continuation. I will show that nonparametric use of continuations
allows very substantial, almost incredible gains in program speed.
Furthermore, this technique is compatible with almost any style of
programming language; imperative, functional, even object-oriented.

This technical report has been published as

Intensional Equality ;=) for Continuations.
Andrew W. Appel, ACM SIGPLAN Notices 31(2), pp. 55-57, February 1996.