the arc of software bends towards understanding
The best and worst thing about semantic import versioning is that it makes BC-breaking changes hard. In the past few days, Russ Cox has made a splash in a series of white papers describing Go and Versioning. In them, he coins a new term, Semantic Import Versioning, distilling it to the following principle: If an […]
Rich Hickey recently gave a keynote at Clojure/conj 2016, meditating on the problems of versioning, specification and backwards compatibility in language ecosystems. In it, Rich considers the "extremist" view, what if we built a language ecosystem, where you never, ever broke backwards compatibility. A large portion of the talk is spent grappling with the ramifications […]
Content advisory: This is a half-baked research post. Abstract. Top-level unpacking of existentials are easy to integrate into Hindley-Milner type inference. Haskell should support them. It's possible this idea can work for internal bindings of existentials as well (ala F-ing modules) but I have not worked out how to do it. Update. And UHC did […]
Ott and PLT Redex are a pair of complimentary tools for the working semanticist. Ott is a tool for writing definitions of programming languages in a nice ASCII notation, which then can be typeset in LaTeX or used to generate definitions for a theorem prover (e.g. Coq). PLT Redex is a tool for specifying and […]
I write in from sunny Oregon, where the sun floods into your room at seven in the morning and the Oregon Programming Languages Summer School is in session. So far, it’s been a blast—with lectures covering Coq, Agda, homotopy type theory, linear logic, logical relations—and we’ve still got another week to go! If you were […]
From the files of the ECMAScript TC39 proceedings Single export refers to a design pattern where a module identifier is overloaded to also represent a function or type inside the module. As far as I can tell, the term “single export” is not particularly widely used outside the ECMAScript TC39 committee; however, the idea shows […]
From the files of the ECMAScript TC39 proceedings I want to talk about an interesting duality pointed out by Mark Miller between two otherwise different language features: weak maps and private symbols. Modulo implementation differences, they are the same thing! A weak map is an ordinary associative map, with the twist that if the key […]
If you hang out long enough with a certain crowd (in my case, it was the ECMAScript TC39 committee), you will probably hear the term membrane tossed around. And eventually, you will start to wonder, “Well, what is a membrane, anyway?” As is the case with many clever but simple ideas, membranes were first introduced […]
Caveat emptor: half-baked research ideas ahead. What is a monad? One answer is that it is a way of sequencing actions in a non-strict language, a way of saying “this should be executed before that.” But another answer is that it is programmable semicolon, a way of implementing custom side-effects when doing computation. These include […]
One of the most mind-bending features of the untyped lambda calculus is the fixed-point combinator, which is a function fix with the property that fix f == f (fix f). Writing these combinators requires nothing besides lambdas; one of the most famous of which is the Y combinator λf.(λx.f (x x)) (λx.f (x x)). Now, […]