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A Visual Language for Types

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Joy
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Jon is a long-time Scala developer, delivering the first commercial and open-source projects in Scala in 2005. He is a former chair of the Scala Center Advisory Board and currently serves as advisor on the Virtus Lab Scala Steering Committee. Jon actively contributes to the Scala open-source ecosystem with Fury, Magnolia and Kaleidoscope, and organizes the annual Scala World conference. He contributes free online training through ScalaZONE and Functional Africa, and provides commercial advanced Scala training courses, specializing in the type system.


Scala has a highly expressive type system for modeling sets of instances, and their properties. But it can be hard for programmers to get a good intuition for what different types represent if we only see types through the source code that describes them.

This talk will be a journey through the Scala type system, examining the wealth of types on offer in Scala 2 and Scala 3, and presenting each in a visual form, showing the relationships between them, and developing an understanding of operations such as finding the least upper-bound of a pair of types. Furthermore, we will see how the concept of categorical duality arises every step of the way.