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.