functional programming

Felienne Hermans argues that Excel is the world's most popular programming language and shows how spreadsheets work as a pure functional language. She implements a few mathematical problems in spreadsheet formulas to illustrate why they are so powerful and approachable.

Richard Feldman argues that functional programming is not the norm largely because of historical accidents, such as C++ popularity, platform exclusivity, marketing spend and network effects, rather than merit. He traces the history of how languages become mainstream.

A Downfall-style parody in which Hitler rages about functional programming concepts such as monads and Haskell. It runs about four minutes.

Jim Weirich's RubyConf 2012 talk derives the Y combinator step by step, live-coding in Ruby lambdas. It builds up an understanding of functional programming and lambda calculus from first principles.

A Lambda Days keynote by Simon Peyton Jones and Tim Sweeney introducing Verse, Epic's functional logic language for the metaverse. It covers existential variables, unification and expressions yielding multiple values.

Gabriel Lebec's Fullstack Academy talk introduces lambda calculus syntax, the history of mathematical logic, and the essence of functional programming using JavaScript. It also covers combinators, currying and Church encodings.

Chris Ford builds up from a single sine wave through layered abstractions to a Bach canon, using Clojure and the Overtone audio environment. The talk shows music theory as a natural fit for functional programming.

Mark Seemann argues that functional programming naturally yields many of the best practices object-oriented developers learn painfully. He shows how functional architecture leads to a pit of success, with a pure core and impure shell.

Part 4 of John Carmack's QuakeCon 2013 keynote, covering OpenGL, functional programming, Haskell, Lisp and Scheme, typing, multithreading, events and garbage collection.

Scott Wlaschin's NDC talk on using statically typed functional programming, F# in particular, to model a business domain. Types are used to represent the domain precisely and to encode business rules so that illegal states cannot be built, with the compiler acting as an instant unit test.

A 1987 talk in which John Backus, creator of Fortran, presents function-level programming and the FL language, a successor to his FP work. It is an archival recording with links to the related paper.

Rafal Dittwald's Clojure/north talk shows how to move from writing Java-style code in Clojure to thinking in data-driven, functional terms. He walks through a JavaScript example, refactoring imperative code step by step into a functional core.

Paul Chiusano's Strange Loop 2019 talk introduces Unison, an open-source functional language for distributed, elastic systems. It covers content-addressed code identified by hashes of the syntax tree, a codebase manager, and algebraic effects called abilities.

Richard Feldman explains how pure functional languages can match or beat imperative ones on performance. Compilers can turn immutable code into in-place mutation, avoiding naive copying. The talk draws on his work on the Roc language.

John Carmack's roughly three-hour QuakeCon 2013 keynote, delivered from a few bullet points. Topics include his Haskell experiments with functional programming and static typing, game state, and cloud gaming.

Michael Arntzenius's Strange Loop talk on Datafun, a functional query language that brings database-style querying into a general-purpose language. It discusses bridging database theory and programming languages.

Scott Wlaschin demystifies functional programming terms like monads, monoids, functors and catamorphisms by showing how they fit into a small toolkit. He applies them to problems such as missing data, list handling, and functional dependency injection.

Guy Steele's Strange Loop 2010 talk argues that programmers should not have to think about parallelism, and that languages should support algorithms built on independence and divide-and-conquer. He also recounts fitting a program onto a single punch card.

Evan Czaplicki's Strange Loop 2014 talk surveys the many formulations of functional reactive programming and how they relate historically and theoretically. It then shows how Elm's variant enables hot-swapping and its time-traveling debugger.

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.

Timothy Daly, an original author of the Axiom computer algebra system, talks about turning a large Common Lisp codebase into a literate program. He argues code should be written as readable manuals, and the talk was given at Write the Docs 2013.

Aditya Siram argues that functional programming has much to learn from Smalltalk's interactivity, using Pharo and Squeak to show live, visual, explorable programming environments.

Zach Oakes explains why Clojure suits making games at runtime, so designers can experience their work as they build it. He combines abstract discussion with live demonstrations, drawing on his play-clj library and Nightmod tool.

Aaron Hsu explains why programmers often find APL harder to learn than people with no programming background. He identifies eight patterns that contrast traditional software engineering practice with APL practice, starting from Ken Iverson's language design principles.

A Strange Loop talk presenting an open-source library that integrates Clojure into the Unity 3D game engine. It covers REPL-based live coding, macros, DSLs and persistent data structures for game development.

Brian Lonsdorf explains why Underscore.js falls short as a functional programming library, then introduces currying, composition and point-free style in JavaScript. He argues for data-last argument ordering.

Rich Hickey's talk on time, state, identity and values, arguing that mutable object-oriented modeling fits the world poorly. It lays out the thinking behind Clojure's approach to data and change.

Tom Stuart's Ruby Manor 3 talk builds FizzBuzz using nothing but Ruby lambdas, working through Church encodings of numbers, booleans and data structures. It is a hands-on introduction to lambda calculus.

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.

Glenn Vanderburg presents Cló, a Clojure library that reimplements TeX's core typesetting algorithms as composable functions. He shows what translating procedural, literate-programming code into functional form teaches.

Rich Hickey's JaxConf 2012 keynote examines what values are and why immutable values matter as information systems grow more complex and data gets bigger. It contrasts places with values and builds the case for immutability.

Jack Rusher's Strange Loop 2022 talk argues that most programming languages are still designed around punchcard-era assumptions. He makes the case for live, interactive programming environments, drawing on Lisp, Smalltalk and REPL-driven development.

Evan Czaplicki, creator of Elm, talks at Curry On 2015 about user-focused language design. He explains the principles behind Elm and how to make a functional, typed language as approachable as JavaScript.

A 2008 Google Tech Talk in which Slava Pestov introduces Factor, a concatenative language influenced by Forth, Lisp and Smalltalk. It covers the interactive environment, metaprogramming, and the language's modern high-level features and libraries.

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.

Shriram Krishnamurthi's PWLConf 2019 talk on the formal notion of expressive power of programming languages, based on Felleisen's paper. It explains how to tell when a feature adds power by whether emulating it requires global rewriting.

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.

Jon Purdy's Stanford EE380 seminar giving an overview of concatenative programming, from function composition theory and history down to low-level implementation and correctness benefits.

Nada Amin's Strange Loop talk on programming languages that build on themselves, centered on towers of interpreters and nestable interpretation in Scheme. She shows how interpreters can be stacked and collapsed.

Dan Friedman and William Byrd demonstrate miniKanren, a logic programming system for Scheme, in an unconference talk. It includes generating programs by running relations in reverse.