Handling control

Non-local control transfer and exception handling have a long tradition in higher-order programming languages such as Common Lisp, Scheme and ML. However, each language stops short of providing a full and complementary approach—control handling is provided only if the corresponding control operator is first-order. In this work, we describe handlers in a higher-order control setting. We invoke our earlier theoretical result that all denotational models of control languages invariably include capabilities that handle control. These capabilities, when incorporated into the language, form an elegant and powerful higher-order generalization of the first-order exception-handling mechanism.