functional programming

A Dyalog demonstration of developing a Sudoku solver in APL, using an algorithm by Arthur Whitney with performance work by John Scholes. The narration steps through the array-oriented solution.

Stephen Wolfram gives a 13-minute tour of the Wolfram Language, a symbolic, functional programming language with a built-in knowledgebase. He demos querying large datasets, interactivity and deployment.

Bruce Hauman live-codes Flappy Bird in ClojureScript in about six minutes, using figwheel to hot-reload changes into the running game. The demo shows game behavior being changed interactively without restarting.

A roughly ten-minute demo of Microsoft's Intentional Programming research system, showing its editor and an unusual way of working with code. It is the first of two clips cut from a longer video.

Part 2 of an old Microsoft Research demo of Intentional Programming, showing the compiler side of a system that stores programs as abstract structure rather than text. The uploader says the companion editor clip is clearer.

A short Dyalog demonstration building Conway's Game of Life in a single line of APL, step by step. It shows how array operations replace loops.

A 12-minute film in which Erlang's creators demonstrate the language's fault tolerance and live-system features, including phoning each other to show it working. This version has fixed audio.

A 1995 Sun Microsystems film about the Self programming language, a prototype-based Smalltalk relative, showing its live, graphical programming environment.

Samuel Falvo II live-codes a text preprocessor and blog engine in Forth over about an hour. It shows Forth's dictionary being snapshotted and restored in place of mutation, and how a small Forth system gets real work done.

A roughly hour-long live hacking session in which Go team members Andrew Gerrand and Brad Fitzpatrick write the new version of tip.golang.org, the site serving leading-edge Go documentation. It is unedited pair programming on a real Go project.

Smalltalk pioneer Dan Ingalls presents the Lively Kernel at JSConf US 2012, a live, direct-manipulation programming environment running in the browser. He shows drag-and-drop building of live objects on the web.

Jonathan Blow demos his prototype programming language, covering the base language and compile-time execution, including running a game while compiling. The video is about 70 minutes of demo followed by Q&A.

Symbolics developer Kalman Reti gives a short introductory demo of a Symbolics Lisp Machine running Genera in an emulator. It shows the context-aware command line, typed on-screen objects, and the live-editable system, including swapping in a C-compiled JPEG decoder.

A demo of the Symbolics Graphics Division's S-Packages, a Lisp-based 3D color graphics and animation system from the 1980s. It was later used in developing for the Nintendo 64.

A short Ericsson film demoing Erlang, showing concurrent processes, debugging tools, and hot code reloading, including crashing parts of a running system while calls continue.

Dave Ackley presents robust-first computing and the ULAM programming language for the Movable Feast Machine, a cellular-automata-like architecture. It was a short video for the Future Programming Workshop 2015.

Alan Kay demonstrates GRaIL, a graphical input language system from around 1968 in which hand-drawn strokes become boxes, connections and dataflow-style programs.

Stuart Halloway introduces REBL, a graphical, interactive tool for browsing Clojure data, extracted from Datomic tools. The talk is from Clojure/conj 2018.

A short film about the Erlang language, showing telecom systems built from lightweight processes and demonstrating hot code swapping. It is an edited version of the original Ericsson video.

A short demo of SEdit, the structure editor for Interlisp-D on Xerox Lisp machines in the 1980s, which edits code as trees rather than text.

A five-minute demo of a live ClojureScript game editor by Chris Granger. It is based on Bret Victor's demo from the Inventing on Principle talk, with code changes reflected instantly in the running game.

Jonathan Blow gives a formal, hour-long demo of his Jai compiler focused on the implicit context feature. The context carries things like allocators through a program without explicit parameter passing, and the talk walks through the code.

A five-minute demo of the Common Lisp debugger fixing a bug, recompiling a single function, and resuming execution from the failed stack frame. It shows how to avoid re-running long computations.

A roughly two-hour demonstration by Dan Ingalls of Smalltalk running on the Computer History Museum's restored Xerox Alto. It shows the integrated environment and language designed at Xerox PARC as personal dynamic media.

A demo of writing technical documents in Emacs Org mode using org-babel, so that code blocks and generated content stay consistent when things change. The author shares the demo files and his dotfiles.

A long George Hotz livestream in which he explores the coronavirus genome and molecular biology from scratch using a browser and Python, hacking on the science in real time.

A 1991 NeXT promotional video that stages a head-to-head programming contest between a NeXT computer and a Sun workstation. It shows NeXT's interface builder and object-oriented tooling producing an application far faster than traditional UNIX development.

A 12-minute demo of the Alternate Reality Kit, built by Randall Smith at Xerox PARC in 1986. It is a simulated physical world in which users manipulate objects and program by direct interaction.

Ashley Feniello demonstrates VimSpeak, a voice-controlled interface for Vim inspired by Tavis Rudd's voice programming talk. The demo includes working through a VimGolf challenge by speech.

Howard Abrams demonstrates, in an EmacsConf 2015 talk, how he uses org-mode's Babel and Tramp to configure and operate remote servers from a single document. Code blocks, their results and the explanatory text all live together.

A 3-minute demo of a tiny IOCCC 2012 winning C program that simulates fluid dynamics in an 80x25 terminal, using any text (including its own source) as input. The video shows the simulation running to Handel's Water Music.

Viznut demonstrates bytebeat, experimental music generated by extremely short C programs. It is the first of a series of videos on the technique.

A 1975 live demonstration of the APL language by Imperial College professor Bob Spence, showing a REPL on a modified typewriter terminal and APL's appeal to non-programmers.

Saqib Shaikh, a blind developer, shows how he writes and debugs code in Visual Studio 2017 using a screen reader. The short demo shows an expert doing ordinary developer tasks.

A short demo of Code Bubbles, an IDE interface built around editable code fragments in bubbles instead of files. It was a research prototype for Java development.

OpenAI's 2021 live demo of Codex translating natural language into code, from Hello World to building a game and a Microsoft Word plugin.

Jon Gjengset spends about three hours livecoding complex changes in a Rust codebase with agentic AI tools, testing his hypothesis that AI is weak at non-pattern work. He documents where Claude Code helps and where it struggles.

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.

A short unscripted demo of writing FizzBuzz in JavaScript with a generator function on a steno keyboard, typos included. It gives a feel for what real coding in stenography looks like.

A brief demo of the Smalltalk debugger, including defining a method that doesn't exist yet while the program is stopped mid-crash.