Professor Alcides Fonseca from the University of Lisbon gave a talk to us

Professor Alcides Fonseca from the University of Lisbon (Portugal) gave a talk to us under the title of Usability Barriers and Design of Liquid Typess.

Title

Usability Barriers and Design of Liquid Types

Presenter

Alcides Fonseca (the University of Lisbon, Portugal)

Abstract

Developers want to detect bugs as early in the development lifecycle as possible, as the effort and cost to fix them increases with the incremental development of features. Ultimately, bugs that are only found in production can have catastrophic consequences. Type systems are effective at detecting many classes of bugs during development, often providing immediate feedback both at compile-time and while typing due to editor integration. Unfortunately, more powerful static and dynamic analysis tools do not have the same success due to providing false positives, not being immediate, or not being integrated into the language. Liquid Types extend the language type system with predicates, augmenting the classes of bugs that the compiler or IDE can catch compared to the simpler type systems available in mainstream programming languages. However, previous implementations of Liquid Types have not used human-centered methods for designing or evaluating their extensions. Therefore, this paper investigates how Liquid Types can be integrated into a mainstream programming language, Java, by proposing a new design that aims to lower the barriers to entry and adapts to problems that Java developers commonly encounter at runtime. Following a participatory design methodology, we conducted a developer survey to design the syntax of LiquidJava, our prototype. To evaluate if the added effort to writing Liquid Types in Java would convince users to adopt them, we conducted a user study with 30 Java developers. The results show that LiquidJava helped users detect and fix more bugs and that Liquid Types are easy to interpret and learn with few resources. At the end of the study, all users reported interest in adopting LiquidJava for their projects.

Bio: Alcides Fonseca is an Associate Professor at the University of Lisbon, Portugal, where he leads the Reliable Software Systems research line. Lately, he has been exploring Liquid Types (e.g., {x:Int | x > 0}) for verification of systems software, typestate and for program synthesis. Despite being 17(!!!) years old, Liquid Types have not been adopted in mainstream languages. In this talk, we will try to find out why.