ETAPS 2019
Sat 6 - Thu 11 April 2019 Prague, Czech Republic
Tue 9 Apr 2019 10:30 - 11:00 at SUN II - Types Chair(s): Vasco Vasconcelos

Algebraic effects and handlers are a powerful abstraction mechanism to represent and implement control effects. In this work, we study their extension with parametric polymorphism that allows abstracting not only expressions but also effects and handlers. Although polymorphism makes it possible to reuse and reason about effect implementations more effectively, it has long been known that naive combination of polymorphic effects and let-polymorphism breaks type safety. While type safety can often be gained by restricting let-bound expressions—e.g., by adopting value restriction or weak polymorphism—we propose a complementary approach, which restricts, instead of let-bound expressions, handlers. Our key observation is, informally speaking, that a handler is safe if resumptions from the handler do not interfere with each other. To formalize our idea, we define a call-by-value lambda calculus that supports let-polymorphism and polymorphic algebraic effects and handlers, design a type system that rejects interfering handlers, and prove type safety of our calculus.

Tue 9 Apr
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10:30 - 12:30: TypesESOP at SUN II
Chair(s): Vasco VasconcelosLASIGE, Faculty of Sciences, University of Lisbon
10:30 - 11:00
Talk
Handling polymorphic algebraic effects
ESOP
Taro SekiyamaNational Institute of Informatics, Atsushi IgarashiKyoto University, Japan
Link to publication
11:00 - 11:30
Talk
Distributive Disjoint Polymorphism for Compositional Programming
ESOP
Xuan BiStandard Chartered Bank, Ningning XieThe University of Hong Kong, Bruno C. d. S. OliveiraThe University of Hong Kong, Hong Kong, Tom SchrijversKU Leuven
Link to publication
11:30 - 12:00
Talk
Types by Need
ESOP
Beniamino AccattoliInria & Ecole Polytechnique, Giulio GuerrieriUniversity of Bath, Maico Leberle
Link to publication
12:00 - 12:30
Talk
Verifiable certificates for predicate subtyping
ESOP
Link to publication