type algebra

A London Haskell talk on the algebra of algebraic data types, showing how sum and product types behave like arithmetic. It frames types as numbers obeying algebraic laws.

The Michigan TypeScript group shows the Doom engine running entirely inside the TypeScript type system. It is open source, and two follow-up videos cover why and how they did it.

An interview with Anders Hejlsberg, lead architect of TypeScript, about porting the TypeScript compiler to Go. He covers the 10x type-checking speedup, lower memory use, and why Go was chosen.

The first chapter of 3Blue1Brown's Essence of Linear Algebra series, introducing vectors with animated geometric visuals. It begins a series that builds intuition for linear algebra from the basics.

A SIGGRAPH 2019 course on geometric algebra. Charles Gunn gives an intro, then Steven De Keninck gives a programmer-focused course with live examples in ganja.js.

A five-minute preview of 3Blue1Brown's Essence of Linear Algebra series, which uses animation to build geometric intuition for topics from a standard linear algebra course.

An animated introduction to geometric algebra, presented as a language that can describe most of physics. It was made with manim and covers multivectors and how they generalize familiar tools like cross products and quaternions.

Jiahao Chen's JuliaCon 2017 talk argues that vector transposes should be taken seriously in type systems and linear algebra libraries. It explains why treating vectors as matrices causes trouble in languages.

A Channel 9 conversation recorded at GOTO 2012 between Anders Hejlsberg (TypeScript) and Lars Bak (Dart). They discuss the two languages and different approaches to making JavaScript development safer, including runtime type checking.

Edwin Brady, creator of Idris, presents Idris 2 and demonstrates type-driven development, where the compiler assists by filling holes and suggesting implementations from types.

Edwin Brady presents Idris 2, a rewrite of the Idris dependently typed language, and shows type-driven development in practice. The demos show the compiler filling in whole functions from their types.

José Valim's ElixirConf US 2023 closing keynote on the foundations of the Elixir type system, covering set-theoretic types and gradual typing with strong arrows.

Aaron Hsu's FnConf18 talk asks whether APL needs a static type system. He argues that APL's expressiveness and rapid iteration already deliver the benefits usually credited to types.

David Christiansen gives a Strange Loop 2018 introduction to dependent types, where one language serves for both compile-time and run-time code and programs unite with proofs. It draws on his book The Little Typer.

CuriousMarc inspects a newly arrived Teletype Model 19, an early military unit built around a Model 15 keyboard and printer, after an initial rough cleaning. It is the first part of a restoration series and touches on 5-bit Baudot code.

Edwin Brady, creator of Idris, introduces type-driven development in a dependently typed language. He shows types being written first and programs derived with interactive editing, then extends beyond simple examples to programs that interact with users and networks.

Professor Brailsford of the University of Nottingham describes how the university set out to print its own mathematics exam papers in the 1980s. The story centers on getting a Mergenthaler Linotron 202 typesetter to work with their own software.

A Ben Heck Show episode tearing down the Nintendo PlayStation prototype, one of the rarest consoles ever, with its owners Terry and Dan Diebold. Part 2 then gets it working again.

Simon Peyton Jones's first lecture on types in Haskell from the Oregon Programming Languages Summer School 2013. It covers type classes and how they relate to OOP, subtyping and polymorphism.

ElixirConf EU 2023 talk by Giuseppe Castagna and Guillaume Duboc on bringing set-theoretic types to Elixir, and the benefits such a type system could offer such as catching bugs.

Philip Wadler's Strange Loop talk on Propositions as Types, the link between logic and computation (the Curry-Howard correspondence). He traces its history through Church, Godel and Turing and shows how it shaped theorem provers and programming languages.

CuriousMarc connects a restored 1930 Model 15 Teletype to a Linux machine and uses it as a terminal, after commenters requested it. The video shows the challenges of linking a 5-bit mechanical device to a modern OS.

Philip Wadler's Lambda Days talk on propositions as types, the link between logic and computation that underlies theorem provers and programming language design.

Edward Kmett speaks at the Boston Haskell meetup about type classes and the design tradeoffs of global coherence compared with other approaches to implicit instances. It covers why uniqueness of instances matters for reasoning and refactoring.

The SILE author's FOSDEM 2015 talk introducing SILE, a TeX-inspired typesetting system with frame-based layout, Unicode, OpenType and a Lua-based extensible design.

Anders Hejlsberg introduces the native port of the TypeScript compiler, written in Go, which promises roughly 10x faster tooling. He demos compiling VS Code and explains where the speedup comes from.

Matthias Felleisen's keynote uses weather prediction as an analogy for type systems, arguing they forecast problems so you can act on them. It draws on his experience developing Typed Racket.

The first lecture of Gilbert Strang's MIT 18.06 Linear Algebra course, covering the geometry of linear equations. It opens a full 35-lecture university course.

3Blue1Brown's chapter on eigenvectors and eigenvalues in the Essence of Linear Algebra series. It builds a visual intuition for what they mean, why an eigenbasis is useful, and ends with a puzzle.

Nadia Polikarpova's Strange Loop talk on program synthesis driven by refinement types, as in Synquid. It shows how rich type specifications can be turned into verified, executable code.

Richard Feldman's elm-conf talk on designing models so that bugs from impossible application states cannot occur, using Elm's compiler and types. It demonstrates techniques for making invalid states unrepresentable.

Rich Hickey's Clojure/Conj 2018 keynote argues that Maybe/Option types and rigid type signatures are a poor way to model data that changes over time. He builds the case around optionality, schema growth and compatibility, and presents the ideas behind Clojure spec as an alternative.

A documentary on the last day the New York Times was printed with linotype machines in 1978, following the process from the newsroom to the press. It marks the move to computerized typesetting.

Freya Holmer's Dutch Game Day 2023 talk asking why vectors can't be multiplied, building from complex numbers to a single axiom and arriving at geometric algebra, quaternions and multivectors.

Dr. Sarah Hallberg argues in a TEDx talk that type 2 diabetes can be treated and potentially reversed through diet, especially by restricting carbohydrates. TED flagged the talk as outside its guidelines and warned against taking it as medical advice.

Bill Hammack of engineerguy uses slow motion video to show how the IBM Selectric typewriter works. He focuses on its fully mechanical digital-to-analog converter, which turns key presses into rotation of the type ball.

Scott Wlaschin shows how statically typed functional languages, using F# examples, can model a business domain so that invalid states cannot be represented. The type system acts almost like an instant unit test at compile time.

Tom Wildenhain's SIGBOVIK 2018 presentation of WordTeX, a Microsoft Word template that mimics LaTeX typesetting output. It is a joke research project executed with serious effort.

Tom 7's pilot episode of a series that plays with type systems and absurd programming, presented as a parody of the GPL v3 license. It mixes a typesetting experiment with a long, story-driven intro on the origin of TeX. Source code and papers are linked from the author's site.

Simon Peyton Jones presents linear types for Haskell, showing how practical linearity can fit into a higher-order polymorphic language. The talk covers motivations such as resource handling and relates the ideas to Rust.