Richard Eisenberg: A Tale of Two Lambdas

A Tale of Two Lambdas: A Haskeller's Journey Into Ocaml
November 6, 2025
Jane Street, 250 Vesey St, New York, NY 10007

NOTE: Please RSVP if you plan to attend. If you arrive unannounced, we'll do our best to get you a visitor badge so you can attend, but it's a last minute scramble for the security staff.

Schedule
6:00 - 6:30: Meet and Greet
6:30 - 8:30: Presentation
8:30 - 10:00: Optional Social Gathering @ Sixpoint Brewery (a very brief walk)

Speaker: Richard Eisenberg

Richard Eisenberg is a Principal Researcher at Jane Street and a leading figure in the Haskell community. His work focuses on programming language design and implementation, with major contributions to GHC, including dependent types and type system extensions. He is widely recognized for advancing the expressiveness and power of Haskell’s type system while making these ideas accessible to the broader functional programming community.

Abstract

After spending a decade focusing mostly on Haskell, I have spent the last three years looking deeply at Ocaml. This talk will capture some lessons learned about my work in the two languages and their communities - how they are similar, how they differ, and how each might usefully grow to become more like the other. I will compare Haskell's purity against Ocaml's support for mutation, type classes against modules as abstraction paradigms, laziness against strictness, along with some general thoughts about language philosophy. We'll also touch on some of the challenges both languages face as open-source products, in need of both volunteers and funding. While some functional programming experience will definitely be helpful, I'll explain syntax as we go - no Haskell or Ocaml knowledge required, as I want this talk to be accessible equally to the two communities.