functional programming

David Beazley's PyCon 2019 tutorial derives the lambda calculus from the ground up in Python, using only single-argument functions. He builds booleans, numerals and more with no other language features.

John Scholes builds a depth-first tree-search operator step by step in a Dyalog APL session. It covers higher-order functions and runs the search on the N-Queens problem.

An episode of FunFunFunction explaining monads in JavaScript as functors that also implement flatMap. It builds on the preceding functor episode and works through code examples.

James Trunk introduces Clojure syntax and thinking, covering its core data structures, immutability, the thread-last macro and live data analysis in the REPL.

Tsoding live-codes a JSON parser from scratch in Haskell in about 111 lines, using only the standard library. It is an edited Twitch stream that explains the intuition behind parser combinators, functors, applicatives and monads.

The first part of a series on programming in Jai, Jonathan Blow's in-development language. It covers compiling, writing hello world and using code from other files.

A screencast tutorial on Specter, a Clojure library for navigating and transforming nested data structures declaratively, demonstrated in a REPL.

The first video in Photon of Scoopex's Amiga hardware programming series. It shows how to set up an assembler and write a minimal 68000 program that waits for a left mouse click.

The first episode of a screencast series building djb's redo build system from scratch in Haskell. It explains the purpose of redo, writes initial code and sets up a GitHub repository.

Day 1 of Casey Muratori's Handmade Hero, a live-coded game built from scratch in C on Windows. It reviews C on Windows, sets up a minimal build system and WinMain entry point, and shows a first MessageBox.

David Sanders gives the first part of a two-part introduction to the Julia programming language at SciPy 2014. It walks through the language's basics and its appeal for scientific computing.

A three-minute Emacs Rocks screencast by Magnar Sveen demonstrating paredit, which edits Lisp code structurally as a tree of s-expressions rather than characters.

Phoenix creator Chris McCord builds a real-time Twitter-style app live with Phoenix LiveView 1.5 in about 15 minutes. It shows interactive, real-time updates without writing JavaScript.

The first stream in the Emacs From Scratch series, building a custom Emacs configuration from zero while teaching basics. It covers a usable baseline setup and the packages for completion, themes and productivity.

A long livestream of George Hotz live-coding a toy SLAM implementation, twitchslam, over two days in May 2018. It is an unedited session of Python programming with computer vision and visualization.

Marco Baringer's tutorial video on SLIME, the Emacs mode for developing Common Lisp. It demonstrates the interactive workflow of working against a live Lisp image.

Bisqwit builds a Doom or Duke Nukem 3D style software-rendered 3D engine in C from scratch, supporting non-Euclidean geometry. It covers vector rotation and portal rendering with sped-up, tool-assisted coding.

Bisqwit writes a NES emulator in C++ in about 15 minutes of tool-assisted, sped-up coding, narrated with captions. It shows an accurate emulator built with a compile-time generated 6502 instruction table. Part 2 covers compiling and running it.

Day 1 of Handmade Hero's introduction to C on Windows, covering setting up Visual Studio, creating a Win32 project, the WinMain entry point and writing a first function. It is the starting point for Casey Muratori's from-scratch game series.

Inigo Quilez live-codes a painting using only mathematics in a shader, building it up step by step. The linked Shadertoy source shows the result.

The first part of a ShaderToy live-coding series that lays the groundwork for The Drive Home, a rainy night-traffic shader. It covers basic setup and builds toward rain and bokeh effects.

Harry Schwartz gives a roughly hour-long tour of Emacs Org mode as an outliner, task manager, markup language and agenda tool. He demonstrates how he uses it for documents, presentations and todo lists.

Markus Triska tours Prolog's most distinctive features, including its use as a database and query language, rule processing, constraint solving and compile-time rewriting. It also covers concise meta-interpreters.

Day 21 of Casey Muratori's Handmade Hero, which covers loading game code dynamically from a DLL on Windows. He builds hot reloading of C game code from scratch in about an hour and a half.

Acerola explores building a shader that turns games into ASCII art, walking through techniques such as brightness mapping and edge detection to see whether it looks good.

A short first episode in Zaiste's Doom Emacs series, showing how to get started with Doom, an Emacs configuration aimed at Vim users. It presents Doom as a polished, fast, batteries-included distribution.

Allieway Audio gives an informal introduction and live-coding demo of ORCA, a free esoteric programming environment for building procedural sequencers from Hundred Rabbits. It walks through the interface and how to make music with it.

David Beazley's workshop screencast builds asynchronous programming in Python from scratch, starting from callbacks and continuations and replacing threads to show how concurrency works underneath.

Bisqwit writes a raytracer from scratch in C++ for DOS, rendering in the 16-color VGA palette at 640x480. The video also covers color quantization and ordered dithering.

A long Tsoding Daily programming stream in which he implements hot code reloading in C by loading a dynamic library at runtime without stopping the main program. It also touches on migrating struct versions across reloads.