Functional Programming for Pragmatists • Richard Feldman • GOTO 2021

This presentation was recorded at GOTO Copenhagen 2021. #GOTOcon #GOTOcph

Richard Feldman - Functional Programming Language Expert & Author of “Elm in Action”

ABSTRACT
Do you care more about how well code works than how conceptually elegant it feels? Are you more interested in how effectively you can build and maintain software than how buzzword-compliant it is? Then this is the talk for you!

People like functional programming for different reasons. Some like it for the conceptual elegance, or the mathematical properties. Richard? He likes to build things. He likes it when the software he builds works well and is easy to maintain. For the past decade he's been using functional programming both professionally and as a hobbyist, and has found it has helped him ship higher quality software in less time than in the decade he spent writing object-oriented code before.
In this talk, he'll share the practical benefits he's enjoyed in FP, and the benefits other pragmatists [...]

TIMECODES
00:00 Intro
04:17 Outline
04:31 Scope: What is functional programming?
06:32 Performance
06:51 Scope: Pure functions
08:55 Performance: Caching
10:57 Performance: Precomputing
12:14 Performance: Parallelizing
15:00 Performance: Performance drawbacks
19:02 Development
19:32 Development: Testing
22:26 Development: Revising
25:49 Development: Debugging
31:18 Development: Development drawbacks
32:35 Ecosystem
38:09 Summary
40:15 Outro

Download slides and read the full abstract here:

RECOMMENDED BOOKS

#FunctionalProgramming #FP #Elm #ElmInAction #Elmlang #Testing #Programming #ProgrammingLanguage #Immutability #PureFunctions #FunctionalLanguages #Debugging #Precomputing #Parallelizing #npm #JavaScript

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[michaelwatson]

Richard Feldman is an excellent teacher. I always learn something from him. It's a good feeling when the light bulb lights up.

[mostafatouny]

Clear, concise, and to the point. Nice how it shows the pragmatic utility using code snippets.

[emanuelerabino]

Inspiring talk. In my opinion the whole industry needs this kind of pragmatic and moderated approach in explaining the value and benefits of FP, instead of fideistic battles.

[bwfrieds]

37:30 is the main point. Limitation is power. Great talk.

[imadetheuniversefun]

18:00 "It's just the thing that would be coming out of the look-up table is a task". That's eye-opening for me, thank you.

[elliotbarlas]

Excellent summary of the merits of functional programming for the pragmatist.

I wish this wisdom replaced the conventional wisdom of Uncle Bob's Clean Code, which is filled with counterexamples. That text seems to revel in solving a problem with the most mutations.

[mortenbrodersen]

Another excellent talk from Richard Feldman!

[SimGunther]

This is a great nuance knowing you have functional AND imperative stuff in your toolbox as you'd default to functional programming for the very reasons he discussed. Nice talk!

[diavolokelevra]

Love the fact that the most replayed sections are about the drawbacks

[jaymanxlife]

Elm sounds too good to be true. Will def. pick this up over the weekend.

[savkelita]

Great video and speech! Thank you Richard.

[gdargdar]

What this guy does would definitely be the next big thing for the evolution of the developer society if they listen. Sadly, today's developers are more attracted to all those shiny new JS frameworks that are garbage in reality.

[teial]

The key here, I think, is the part about dependencies. Either they are implicit (which might bite us back), or we make them explicit but introduce verbosity instead (which can lead to confusion). So it is a tradeoff, as usual. We can sort of circumvent it by making PL itself bear the burden of providing developers with explicit and clear abstractions for dependency management (like algebraic effects and *not* like Haskell's do-notation). But this means that either 1) developer must spend more time learning the language which is sort of okaish or 2) PL developers need to spend more time designing the language.

[shahidkhan]

he really convinced me about functional programming

[austinnar]

One benefit that I would love to see a language add: In pure functional languages you can automatically skip computations that do not lead to any effect. You can treat the entire program as a directed graph where the function calls are nodes and the edges are values. Any node that does not have path to a task (something that produces user-visible output) can be removed from the graph without affecting the program

[MarkusBurrer]

I love to listen to this guy. But I should start coding

[hughoxford]

I choose functional techniques out of fear

[ruiw]

is managed effect just like a thunk (wrapper fn) scheduled by main function? At 21:48, when Richard talked about simulation, it sounds like a stubbing in oop.

[jackgenewtf]

I think you know this, Richard, and probably just want to avoid introducing too much terminology into the talk. But I just wanted to point out that at 28:49, technically, if the function has side effects, it isn't "pure", it is "idempotent" though, which I believe is what you meant.

[bicatu]

how about integration tests? unless your program does not interact with any external dependency they will still be flaky as it depends on the actual behavior of other things outside your function, right?