QCon San Francisco 2021 November 1-5, 2021 | | Category Theory for the Working Hacker

What You’ll Learn

How functional languages can benefit from a different perspective on types.
How category theory has contributed to modern functional programming.

Abstract

The talk will explain why category theory is of interest for developers. The principle of Propositions as Types describes a correspondence between, on the one hand, propositions and proofs in logic, and, on the other, types and programs in computing. And, on the third hand, we have category theory! Assuming only high school maths, the talk will explain how categories model three basic data types: products (logical and), sums (logical or), and functions (logical implication). And it explains why you already learned the most important stuff in high school.

Question:

What do you do day-to-day?

Answer:

I work in functional programming and trying to put that in a place where other people can use it.

Question:

What is your motivation for this talk?

Answer:

Category theory is the secret sauce that underlies a lot of functional programming. For instance, monads have become quite popular. The original ideas were developed by category theorists, and part of my contribution was to explain the ideas so you can use then without knowing any category theory. But if you do know category theory, then you have a chance to see where the next idea is coming from.

In the talk, I’m going to focus on three basic data types: products, sums, and functions. I’m going to talk about how they look in category theory, and how that translates to Java and Haskell, and some deep and beautiful symmetries that tie everything all together.

Question:

Who should come to your talk?

Answer:

Developers who are interested in understanding some of the fundamental ideas that underpin the design of programming languages.

Question:

What can people come take away from this talk?

Answer:

An understanding of the three most basic data structures in programming, how variants are really records turned on their head, and how the most important ideas are ones they already learned in high school.

Speaker: Philip Wadler

Haskell, Type Theory, & Functional Programming Theory Contributor

Philip Wadler is Professor of Theoretical Computer Science at the University of Edinburgh and Senior Research Fellow at IOHK. He is an ACM Fellow, a Fellow of the Royal Society of Edinburgh, and editor-in-chief of Proceedings of the ACM for Programming Languages. He is past chair of ACM SIGPLAN, past holder of a Royal Society-Wolfson Research Merit Fellowship, winner of the SIGPLAN Distinguished Service Award, and a winner of the POPL Most Influential Paper Award. Previously, he worked or studied at Stanford, Xerox Parc, CMU, Oxford, Chalmers, Glasgow, Bell Labs, and Avaya Labs, and visited as a guest professor in Copenhagen, Sydney, and Paris. He has an h-index of 66 with more than 22,000 citations to his work, according to Google Scholar. He contributed to the designs of Haskell, Java, and XQuery, and is a co-author of Introduction to Functional Programming (Prentice Hall, 1988), XQuery from the Experts (Addison Wesley, 2004) and Generics and Collections in Java (O'Reilly, 2006). He has delivered invited talks in locations ranging from Aizu to Zurich.