This paper investigates algebraic effects and handlers from the
viewpoint of well-established work on the four delimited continuation
constructs known as shift, control, shift0, and control0.
The whole development follows what Danvy and his colleagues have laid
out.
We start by defining two definitional interpreters for algebraic
effects and handlers based on trails as introduced for dynamic
continuation-passing style translation and metacontinuations as
introduced for a hierarchy of control operators.
Once definitional interpreters are obtained, we transform them
using well-known meaning-preserving program translations to obtain
abstract machines for algebraic effects and handlers.
We also derive monomorphic type systems for algebraic effects and
handlers by assigning types to the definitional interpreters,
ones similar in spirit to the type system for shift and reset with
answer type modification.
The resulting semantic artifacts are close to those for delimited
continuation constructs, enabling cross-fertilization between
delimited continuation constructs and algebraic effects and handlers.