Sam Lindley is giving this month's EdLambda talk on Tuesday 17th at 7pm

at The Outhouse pub. It'll be based with Ohad Kammar and Nicolas Oury:

"Handlers in action". Sam will probably focus mostly on examples from

their Haskell effect handler library, perhaps with some live hacking.

Abstract

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Plotkin and Pretnar’s handlers for algebraic effects occupy a sweet spot

in the design space of abstractions for effectful computation. By

separating effect signatures from their implementation, algebraic

effects provide a high degree of modularity, allowing programmers to

express effectful programs independently of the concrete interpretation

of their effects. A handler is an interpretation of the effects of an

algebraic computation. The handler abstraction adapts well to multiple

settings: pure or impure, strict or lazy, static types or dynamic types.

This is a position paper whose main aim is to popularise the handler

abstraction. We give a gentle introduction to its use, a collection of

illustrative examples, and a straightforward operational semantics. We

describe our Haskell implementation of handlers in detail, outline the

ideas behind our OCaml, SML, and Racket implementations, and present

experimental results comparing handlers with existing code.