Please log in to watch this conference skillscast.
Abstraction is a Haskell programmer's best friend. Our choice of good abstractions, identifying which details to hide from other parts of the system and which to expose in interfaces, is crucial to our ability to craft correct, concise and meaningful programs. Haskell gives us the ability to express abstractions at many levels without incurring significant performance penalties. But can it capture all the abstractions we might want?
The concept of lenses in general, and the lens library in particular, have revolutionised modern Haskell programming. The lens library is full of abstractions that allow expert users to write amazingly concise code, but these are sometimes baffling to the uninitiated. Not for nothing has the library been described as a separate language that happens to be embedded in Haskell. Significantly, the key concepts expressed in the library (optics such as lenses, traversals and prisms), are not in fact abstract data types. Rather, they are type synonyms, which expose the underlying implementation. This gives a lot of power and flexibility to combine optics, but allows implementation details to leak into inferred types and error messages.
In this talk, you will discover an attempt to capture optics such as lenses using abstract data types, while maintaining as far as possible the expressive power of the lens library. Clearly distinguishing between the interface and implementation of optics will help illuminate their nature and purpose. Moreover, I will reflect on the power and limitations of abstraction in Haskell itself.
This talk will be suitable for Haskell programmers of a range of skill levels. Only basic Haskell knowledge will be required, and familiarity with the lens library will not be assumed, although having been baffled by it at least once is a worthwhile experience for anyone.
YOU MAY ALSO LIKE:
- Coping with change: data schema migration in Haskell (SkillsCast recorded in October 2014)
- Real World Kotlin Development Workshop (in London on 22nd - 23rd October 2019)
- Lightbend Akka for Scala - Professional (in London on 11th - 12th November 2019)
- Clojure eXchange 2019 (in London on 2nd - 3rd December 2019)
- Scala eXchange London 2019 (in London on 12th - 13th December 2019)
- Code Kata: Yilin Wei - Optics with Monocle (in London on 22nd October 2019)
- Reprogramming Biology with F# (in London on 28th November 2019)
- Lightning Talk: Making and Testing Code Generators in Haskell (SkillsCast recorded in October 2019)
- GHC Runtime Linker by Example (SkillsCast recorded in October 2019)
Through a Glass, Abstractly: Lenses and the Power of Abstraction
Adam currently works as a Haskell Consultant for Well-Typed LLP. He is a keen Haskell programmer, and completed a PhD in 2013 on combining Haskell with dependent types.