Handlers of Algebraic Effects

We present an algebraic treatment of exception handlers and, more generally, introduce handlers for other computational effects representable by an algebraic theory. These include nondeterminism, interactive input/output, concurrency, state, time, and their combinations; in all cases the computation monad is the free-model monad of the theory. Each such handler corresponds to a model of the theory for the effects at hand. The handling construct, which applies a handler to a computation, is based on the one introduced by Benton and Kennedy, and is interpreted using the homomorphism induced by the universal property of the free model. This general construct can be used to describe previously unrelated concepts from both theory and practice.

• Type: Conference
• Year: 2009
• Where: ESOP
• Authors: Gordon D. Plotkin, Matija Pretnar
• Keywords: Algebraic Theory, Computation Monad, ESOP 2009, Exception Handlers, Programming Languages