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ICFP 2020
Thu 20 - Fri 28 August 2020
Sun 23 Aug 2020 10:45 - 11:30 at HOPE - Keynote and Session 1

Functional reactive programming (FRP) is a paradigm for programming with signals and events, allowing the user to describe reactive programs on a high level of abstraction. For this to make sense, an FRP language must ensure that all programs are causal, and can be implemented without introducing space leaks and time leaks. To this end, some FRP languages do not give direct access to signals, but just to signal functions.

Recently, modal types have been suggested as an alternative approach to ensuring causality in FRP languages in the synchronous case, giving direct access to the signal and event abstractions. This paper presents Simply RaTT, a new modal calculus for reactive programming. Unlike prior calculi, Simply RaTT uses a Fitch-style approach to modal types, which simplifies the type system and makes programs more concise.

In the context of modal FRP, the delay modality is used to represent computations that can be executed in the next time step. This is a computational effect and controlling this is crucial for FRP as many space and time leaks arise from moving computations across time steps. Echoing a previous result by Krishnaswami for a different language, we devise an operational semantics that safely executes Simply RaTT programs without space leaks.

Sun 23 Aug

Displayed time zone: Eastern Time (US & Canada) change

08:00 - 11:30
Keynote and Session 1HOPE at HOPE
Variants of call-by-push-value
Paul Blain Levy University of Birmingham
Kripke open relations and operational game semantics
Guilhem Jaber Université de Nantes, Andrzej Murawski University of Oxford
Merging coeffect production into effect handling
Tarmo Uustalu Reykjavik University, Tallinn University of Technology, Niels Voorneveld Tallinn University of Technology
Simply RaTT: A Fitch-style Modal Calculus for Reactive Programming
Patrick Bahr IT University of Copenhagen, Christian Uldal Graulund IT University of Copenhagen, Rasmus Ejlers Møgelberg IT University of Copenhagen