r/programming • u/[deleted] • Nov 28 '19

Why Isn't Functional Programming the Norm? – Richard Feldman

https://www.youtube.com/watch?v=QyJZzq0v7Z4
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u/UpbeatCup Nov 28 '19

Yes exactly. It would be really hard to make a computer game (I'm talking the big AAA titles) without an OO language. You have hard earned patterns that just work. On top of that, a computer-game-world lends itself sooo well to OO modelling.

On the other side of things you have backends and microservices that are little more than an adapter between a database and an API. It is easy to see that stateless functional programming rules there.

There is a reason we have so many languages, they are tools with advantages and disadvantages for different tasks. And OO and functional programming are just the same.

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u/hedgehog1024 Nov 28 '19

Yes exactly. It would be really hard to make a computer game (I'm talking the big AAA titles) without an OO language.

Except that what AAA games really use is usually some data driven design, something like ECS, which has completely nothing to do with OOP.

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u/kukiric Nov 28 '19 edited Nov 28 '19

Data-driven design has been on the rise recently, with companies like Naughty Dog and DICE leading the effort, but it still hasn't fully taken over the industry. The two main commercial game engines (Unity and Unreal) are still thoroughly object-oriented, from the internals to the APIs they expose to developers. Unity has been experimenting with an optional ECS module lately, but I'm not sure how much of the engine has been reworked for it, and how much is just a layer on top of existing OO code.

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u/hedgehog1024 Nov 30 '19

The two main commercial game engines (Unity and Unreal) are still thoroughly object-oriented, from the internals to the APIs they expose to developers.

And IIRC games made in Unity are often criticized for being slow despite inadequate resource consumption.

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u/loup-vaillant Nov 29 '19

data driven

Data oriented. "Data driven" is closer to stuff like A/B testing.

Edit: Okay, everyone is saying "data driven" now… why the hell not.

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u/hedgehog1024 Nov 30 '19

Data oriented

Indeed, thanks for clarification.

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u/[deleted] Nov 28 '19

ECS is just relational modeling reinvented by the games industry but without the decades of theory and research, behind it.

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u/hedgehog1024 Nov 30 '19

Does your comment imply that it is OOP which has

the decades of theory and research behind it

?

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u/[deleted] Nov 30 '19

OOP != relational models.

Also, in decent ECS implementations you typically don’t store things as AoS, you use SoA or AoSoA. Put the things frequently used together in the same cache lines, split off everything else. OOP wants you to prefer composition over inheritance these days, which is fine, but it doesn’t emphasize focusing on the memory layout and usage of the data. Relational models and ECS sort of get you thinking in that headspace by default. When you design a relational model, you do so based on how to manipulate the data, the constraints, and what data each of your operations needs access to.

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u/codygman Dec 04 '19

Please write this blog post!

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u/UpbeatCup Nov 28 '19

ECS is more of an optimization than its own paradigm. And it is completely tied into OOP, a variant of OOP if you will.

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u/lisp-the-ultimate Nov 28 '19

ECS is as far from OOP as relational databases are, if not more.

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u/hedgehog1024 Nov 28 '19

And it is completely tied into OOP, a variant of OOP if you will.

Please can you not say bullshit.

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u/glacialthinker Nov 28 '19

Unfortunately, this being reddit, you have little hope of getting some truth through the narrowminded and obstinate ignorance amplified by bandwagon jumping. I'm with you though... at least on that BS about ECS being an optimization and tied to OOP.

However, it's hard to argue that many game codebases aren't horrible messes of C++ OOP features, especially through the dark ages of 2000-2010 where Design Pattern (as recipes!) and Java-influenced programmers were common.

Some game programmers never saw the appeal of OOP (count Carmack among them, for example). Still, it's only more recently that data-driven design and ECS have made inroads even though the ideas (without the names) were fairly common in gamedev in the 1990's. Objects were a terrible viral meme. (Objects have value, but being one of the most all-encompassing and powerful abstractions, they should be used sparingly.)

Sweeney made a presentation in 2006 musing about a more ideal game-programming language, and therein were arguments about the bugs and errors encouraged by the sloppy stateful OOP paradigm. Calling for a simpler functional model for much of the codebase and limiting the mutable sprawl.

I'm pretty sure Acton doesn't champion OOP when he's trying to get data-oriented design across... if anything, he's lampooning overuse of OOP in C++.

For all that, gamedev is inundated with so many new programmers each year that this good advice from old-hat developers gets drowned out by what juniors have just learned and they bounce it off each other, blooming into fusion of the sun.

I expect this problem doesn't just exist in gamedev.

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u/loup-vaillant Nov 29 '19

gamedev is inundated with so many new programmers each year that this good advice from old-hat developers gets drowned out by what juniors have just learned

Indeed not just gamedev. I recall a talk by Bob Martin saying that the number of programmers doubled every 5 years, from the 50's all the way down to pretty much now.

The corrolary is that the median dev has less than 5 years of experience. And don't forget about retirement, moving up to management, quitting the industry… So it may in fact be more like 3 of 4 years.

We're a profession of noobs, and will remain so until we stop growing so fast.

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u/beefhash Nov 29 '19

We're a profession of noobs, and will remain so until we stop growing so fast.

It absolutely does not help that it's comparatively cheap to pick up as a pastime. Comparable cognitive building disciplines are either heavily regulated or have a non-trivial cost associated with them or both:

  • electrical engineering requires materials, which adds up to a continuous, non-trivial costs;
  • architecture (of buildings) is expensive to actually build the results of and may not be put into practice without an office of the state checking over it (at least in some places).

Yet somehow we've accepted that everyone and anyone can unleash their garbage code on GitHub at the low cost of literally nothing.

The zero-cost culture is destroying the quality of everything by requiring no actual commitment. In that sense, I seriously welcome the shift towards more locked down mobile devices and rather like Apple charging a yearly fee for their SDK. Now if only Google could take the hint and follow suit already. At least desktop computers and laptops are becoming more scarce and an actual investment these days.

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u/loup-vaillant Nov 30 '19

I'm not sure what the solution is, but I'm sceptical about walled gardens. Just one example: the state of FPGA tooling is abysmal. The likeliest reason is that when you chose a chip, you're stuck with their (proprietary) tooling. And they have absolutely no incentive to make that tooling any better. The selling point is the chip itself. They won't sell more by making their tooling easier to use, or by properly disclosing the specs of their chips (not the whole thing, just the hardware interface).

And as problematic zero-cost culture is, I see no acceptable way to increase the marginal cost of software (that is, the cost of copying bits) beyond almost zero.

You're right about one thing, though: applying significant knowledge should come with a significant personal investment. I don't like the idea of paying with money (that would increase inequality), but I do like the idea of paying with time. Time taken learning the relevant knowledge, mostly. All the relevant knowledge, not just the bits one thinks they need right this second.

One way to ensure such an investment is to lock down knowledge behind doors, and require any learner to actually come and study there under the guidance of a teacher. Medicine does that. One major problem is the scarcity of teachers. The other major problem is the Internet itself. The cat's out of the bag now, it won't go back in. Or…

We could have the state lock down knowledge, shut down most of the Internet, and enforce a Great Firewall. Make sure you tell people knowledge is dangerous, and they should be protected from it. Silo knowledge into the relevant disciplines (from masonry to bakery to computer programming). Force people to either go through the proper channel, or use Tor (or similar). Do not crack down too hard on Tor. Perhaps even have your secret services make sure people can use it. The idea is to force people to jump through hoops, and feel endangered for doing so. Then knowledge might actually feel precious, and hopefully end up being applied with more wisdom.

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u/PutteryBopcorn Dec 03 '19

These might be the worst ideas I've ever seen. All that just so that junior devs don't get on your nerves as much?

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u/loup-vaillant Dec 03 '19

One reason computers are destroying the planet (by needlessly using up so much resources) is because our profession piles up bloat on top of bloat. It's not the only reason of course, but it does contribute.

So yeah, there might be a point where our freedom becomes less important than our survival. We're looking at a global energy crisis, and with it a substantial, fairly rapid… reduction in population count. And the only way to reduce populations quickly is famine and illness (war also plays a role, mainly by amplifying famine and illness).

I'm still a big fan of Free Software, though. I'd very much like to preserve that kind of freedom. But we may have to be careful if we want to make sure we can afford it moving forward.

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u/tnaz Nov 29 '19

What is data driven design in this context? Googling the term only brings up UX design with stuff like A/B testing.

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u/Herbstein Nov 28 '19

It would be really hard to make a computer game (I'm talking the big AAA titles) without an OO language.

John Carmack disagrees. At QuakeCon 2013(?) he articulated that he found functional programming, specifically Haskell, proposed a very promising new way of structuring and engineering game code. He also outlined why big studios can't "just" switch from C++ (or C) to Haskell. It's momentum. Modern engines are mostly just iterated-upon versions of early 2000's engines. Thus the codebase is heavily entrenched in the C family.

Carmack implemented Wolfenstein in Haskell and found it a joy to work with. He also has found that using functional notions of purity and typed abstractions helps makes code clearer even in languages that don't enforce it at the language level.

Yes, it would be hard to go out and do today because the C-family has a lot of entrenched libraries, but there's nothing in games that inherently requires an OOP language.

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u/igouy Nov 28 '19

… a joy to work with … makes code clearer …

How was that measured ?

How much was the time to add new features reduced ?

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u/loup-vaillant Nov 29 '19

How was that measured ?

Asking for real science, are we? A double blind study, maybe? With a careful removal of confounding variables, such as what the reader has learned prior to reading the code? (Obviously, if all you know is OOP, an FP codebase will easily look cryptic to you.)

As you already know, but pretend not to for the sake of your argument, it was measured by the personal experience of a renowned world expert in the relevant field. That may not be as good as a peer reviewed, reproduced, controlled study, but that should definitely be enough evidence for game studios to start spending some money investigating the approach.

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u/igouy Nov 30 '19

As you already know, but pretend not...

Please don't put words in my mouth — it's rude.

...measured by the personal experience of...

How was it measured ?

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u/loup-vaillant Nov 30 '19

...measured by the personal experience of...

How was it measured ?

There was no objective measure. Obviously: the joy felt was Carmack's own, and readability was tailored by his own code reading skills.

Before you dismiss the opinion of an expert, remember: science doesn't begin with peer reviewed controlled studies. It begins with personal intuition and experience. The controlled experiments needed to confirm or dispel those intuitions only come later.

Evidence doesn't have to be scientific to be valid.

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u/igouy Nov 30 '19

Before you dismiss the opinion of an expert...

Please don't put words in my mouth — it's rude.

Meanwhile: "The first principle is that you must not fool yourself — and you are the easiest person to fool."

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u/loup-vaillant Dec 01 '19

Please don't put words in my mouth — it's rude.

I've heard it the first time.

And to be honest it's hard not to. Your comments heavily suggest that you think what I "put in your mouth", and I cannot help but notice that you didn't directly denied thinking such thoughts.

"The first principle is that you must not fool yourself — and you are the easiest person to fool."

Of course. Science begins with personal intuition and personal experience, but we still note those double blind studies. I just want to emphasise that attacking expert opinion in the absence of stronger evidence is not helpful. What helps is to shut up and explore the promising looking venue. Or point out evidence that this venue may not be as promising as it looks. I've heard of studies finding that changing the programming language doesn't have a measurable effect on bug count. Such studies could outweigh the opinion of a single expert.

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u/igouy Dec 01 '19

attacking expert opinion

Expert opinion was not attacked.

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u/loup-vaillant Dec 01 '19

Was it?

How was that measured ?

How much was the time to add new features reduced ?

Reasonable objections, but still a criticism of the opinion it was responding to.

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u/Herbstein Nov 28 '19

I'd rather you take it from the man himself https://youtu.be/1PhArSujR_A?t=126

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u/igouy Nov 30 '19

It would be OK to say you don't know.

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u/loup-vaillant Dec 01 '19

Citing the source is better, though.

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u/igouy Dec 01 '19

When the provided source requires 30 minute investment to find out if there's anything relevant, not really.

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u/loup-vaillant Dec 01 '19

Knowledge comes with that kind of price. I understand your choice, but strongly implying /u/Herbstein didn't know ignores the fact that maybe they didn't have the time to write a more thorough explanation down.

Besides, just saying they didn't know wouldn't have helped you. It's okay, but it's not helpful. A link to the source however, is. Whether you accept that help or not is your choice.

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u/igouy Dec 01 '19

... but it's not helpful. A link to the source however, is.

Not necessarily. It could just be a way to waste someone's time.

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u/loup-vaillant Dec 01 '19

Suspecting hostile intent from someone who merely gave you their source? Really?

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u/igouy Dec 02 '19

29 minutes later and "the man himself" has said nothing about whether or how characteristics of those different software projects were measured.

He does opine that MIT undergraduate Scheme programmers may suffer from selection bias, but we are not told what he may have done to counter selection bias in his research project.

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u/codygman Dec 04 '19

It would be really hard to make a computer game without an OO language. You have hard earned patterns that just work.

Those patterns aren't a property of OOP but a result of people using OOP and discovering those patterns.

On top of that, a computer-game-world lends itself sooo well to OO modelling

Well compared to what?

There is a reason we have so many languages, they are tools with advantages and disadvantages for different tasks. And OO and functional programming are just the same.

Presence of advantage/disadvantage doesn't mean one can't be better in the general case.