Algebraic Subtyping is a type system devised by Stephen Dolan in 2016, in his dissertation. It extends Hindley-Milner with subtyping, in a way that preserves decidability and principality. Over the past few years, I have implemented Algebraic Subtyping in my language Pinafore (omitting record types). Pinafore is, as far as I know, currently the only […]
A much smaller update, this time. The main improvement is a reworking of dynamic types. Before, they had to be defined bottom up, that is, you had to define the concrete types first, and then define abstract supertypes in terms of them. Now, however, you can define the types in any order, and then simply […]
Pinafore is an interpreted purely functional language using Algebraic Subtyping that explores structuring information and composing graphical user interfaces. It has a number of unusual features, some fairly trivial, some more significant, some occasionally found in other programming languages, and some I believe are entirely unique to the language. Haskellish Things As an interpreted language […]
I’ve just released version 0.4 of Pinafore, representing more than a year’s worth of full-time work since the last release. I’ll make another post shortly explaining what Pinafore is all about and what makes it unusual, but in the mean time, this is the release notes for the new version: — Ashley Yakeley
Monadology is intended as a collection of the best ideas in monad-related classes and types, with a focus on correctness, elegance and theoretical understanding. I am interested in hearing further ideas, so at least initially expect a lot of change version-to-version. Re-exported Transformers Monadology is built on the existing transformers package. It re-exports most of […]
This is largely in response to Nassim Taleb’s paper Bitcoin, Currencies, and Fragility. I don’t know much about finance or economics, this is merely my best guess and I may have made some elementary errors, or missed some possibilities. The relentless volatility of Bitcoin and other cryptocurrencies continues to astonish me. As far as I […]
I had more planned for Pinafore 0.3, but two things happened: I found a bug in the type-checker that absolutely had to be fixed, and took me awhile to figure out. And last week I started full-time work, so I wanted to get a version out now, since I won’t have much time to work […]
Pinafore was originally motivated by my desire to organise and structure (i.e., type) various bits of information relating to my life. This is why, for instance, the example Pinafore code in the documentation relates to contacts and events. After I released Pinafore 0.1, I spent some time actually trying to do this, and ran into […]
For some reason GADTs are a particular sticking point for many advocates of Simple Haskell. But sometimes GADTs are the natural form of expressing a concept. By way of example, here’s a snippet of API I’ve borrowed from JuicyPixels: JuicyPixels was originally released in 2012, and there’s always a good presumption against changing an API, […]
The promise of Haskell over other languages is that it allows you to more cleanly and intuitively represent the application domain. This leads to more intelligible and maintainable code. But to take full advantage of what Haskell has to offer, you have to embrace the whole language. This means making use of any appropriate language […]