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The Evolution of Effects (Keynote) (Video, Haskell 2023) Nicolas Wu (Imperial College London, UK) Abstract: Functional programming has been celebrated for its promise of pure functions, delivering referential transparency and elegant reasoning about programs. However, real-world applications are not pure, and necessitate interaction with the outside world, introducing computational effects such as IO, state, and exceptions. The journey to harmonize these seemingly contradictory paradigms has led to a fascinating evolution of effectful programming in Haskell. The introduction of monads as a practical programming tool was a pivotal discovery, enabling controlled sequencing of effectful computations and addressing the challenge of handling side effects in a pure language. However, it soon became evident that the lack of modularity in composing effects using monads posed a limitation to effectful programming. To overcome this obstacle, monad transformers emerged as a solution, providing a composable manner of building effects on top of one another. More recent advancements have led to algebraic effects as an alternative framework that is easy to extend, particularly as domain-specific languages crafted to work in specific contexts. Nevertheless, these effects are not without quirks and limitations, leading to the development of higher-order effects. These higher-order effects extend the capabilities of algebraic effects, providing greater flexibility for expressing effectful computations, while also shedding light on the connection between the monad approach and the algebraic approach to effects. This talk will survey the historical milestones that have shaped the landscape of effectful programming in Haskell, exploring the transition from monads to monad transformers and the emergence of algebraic and higher-order effects. Article: https://doi.org/10.1145/3609026.3615581 ORCID: https://orcid.org/0000-0002-4161-985X Video Tags: icfpws23haskellmain-key2-p, doi:10.1145/3609026.3615581, orcid:0000-0002-4161-985X Presentation at the Haskell 2023 conference, September 8–9, 2023, https://icfp23.sigplan.org/home/haskellsymp-2023 Sponsored by ACM SIGPLAN, https://www.sigplan.org/

Luau is the first programming language to put the power of semantic subtyping in the hands of millions of creators.

A guide to domain-specific types that make sense.

Luau is the first programming language to put the power of semantic subtyping in the hands of millions of creators. Minimizing false positives One of the issues with type error reporting in tools like the Script Analysis widget in Roblox Studio is false positives. These are warnings that are artifacts of the analysis, and don’t correspond […]

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I have long struggled to understand what a logical relation is. This may come as a surprise, since I have used logical relations a bunch in my research, apparently successfully. I am not afraid to admit that despite that success, I didn't really know what...

Hacky repo to see what the Copilot extension sends to the server

Way back in 2016 I wrote a couple of (now mostly outdated) blog posts talking about how types and declarations are represented in the compiler, and at the time I promised a third installment which would discuss generics. A few of you have asked me about this over the years... Well, I finally got around to starting a write up about how generics work last year, and I think I its finally in good enough shape that I can release the first part of what is going to be a three part series. So here it i...

I don't mean to complain. Doing software engineering for a living is a situation of extreme privilege. But there's something to be said about how alienating it can be at times. ...

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Computer security as a field is met with a persistent criticism:flashy attacks arehot,boring (hard-fought) defenses arenot. Comparedto security, programming ...

I recently decided to confront the fact that I didn't know what "realizability" meant. I see it in programming languages papers from time to time, and could see little rhyme or reason to how it was used. Any time I tried to look it up, I got some nonsense...

Many are well aware of the hazards of race conditions. But what about the benefits?