[eloff]

Lack of generics != lack of abstractions.

The Go community freely acknowledges that generics are a nice feature, and that lacking them is a pain point of Go sometimes. Although many Go developers will tell you that sometimes turns out to be not that often in reality, which has also been my experience.

Rob Pike has outlined the tradeoffs inherent with generics here: http://research.swtch.com/2009/12/generic-dilemma.html

The bottom line is it's not a feature that comes for free, and if most of the time you don't really need it, maybe the costs aren't worth it. That's a bold statement for a programming language these days, since generics is a central feature of every popular, modern, statically typed language. Whether they are right or wrong I won't attempt to say. The language may well get generics one day, but it's early days still and the team is rightly focusing on more important features for the moment.

[spion]

That really depends on what you mean by "most of the time". After all, you only write a generics based library once, and you reuse it many times - therefore on the outside it appears that you don't really use generics all that much.

In my opinion, depriving a "normal" language user of generics is like depriving a Lisp user of macros. Whatever it is, its definitely not just "bold".

[eloff]

I've done most of my Go programming on library code. A sync library for relational databases to sqlite (for mobile devices) and an embedded database. Lack of generics has bothered me a little, but copy and paste with a multiple-cursor editor really makes short work of it. I think the worst part is really our natural aversion to code duplication and the ugliness of it. e.g. having to write min/max for integers is pretty ugly (although not as ugly as converting your ints to float64 and using the stdlib min/max.) However, I spent more time thinking that it was ugly than writing min and max. Sure it's ugly, but programming is not art, it's engineering, and Go is a language for engineers.

[apta]

> I think the worst part is really our natural aversion to code duplication and the ugliness of it. e.g. having to write min/max for integers is pretty ugly

Sometimes ugliness is a sign that something is designed incorrectly, especially if the language aids in making that more visually evident.

> (although not as ugly as converting your ints to float64 and using the stdlib min/max.)

Not to mention incorrect.

> it's ugly, but programming is not art, it's engineering

Not mutually exclusive. A good language would make incorrect or inefficient code "ugly" or "uglier" than correct code.

> and Go is a language for engineers.

So are languages with generics like C++, Java, Rust, Haskell, etc.

[pmontra]

Plus all those dynamically typed languages which are intrinsically built on the concept of generics (JavaScript, Perl, PHP, Python, Ruby). /sarcasm Nobody uses them because nobody needs generics.

[tel]

They are intrinsically built atop generics. Duck typing is row polymorphism. Dynamic languages often depend upon that flexibility to operate—and they enable it by allowing everything. Static languages without polymorphism are at a low point in that trade-off space since they restrict useful operations and provide no way to express the invariances needed to recover that flexibility.

[echaozh]

I never thought people will actually come up and defend code duplication. It's definitely more than ugliness. The need to fix all the copies when they need to be updated is a bigger problem.

[apta]

Or the fact that I actually saw someone on the mailing list also implement min() incorrectly due to copy-paste :)

> I never thought people will actually come up and defend code duplication.

Indeed. Some of the responses by some Go fans really leave me surprised to say the least.

[pjmlp]

It was the community attitude towards generics and code distribution that eventually made me focus on Rust and D.

At least those communities embrace modern computing abstractions and code distribution practices.

[nknighthb]

It's fine that you don't agree with our tastes, but it would be nice if you could stop coming into every Go thread and being condescending about it.

Like PostgreSQL and OpenBSD, I've been permanently turned off Rust because I never want to be left at the mercy of a community that invests so much time in harassing and insulting others.

[spion]

Yeah, the deficiency isn't the most harmful part - its the attitudes that come with defending that deficiency.

[sagichmal]

    > I never thought people will actually come up and defend   
    > code duplication.

DRY is a principle, not an axiom.

Overapplication of DRY as axiomatic has led to much pain and suffering.

[the_af]

Agreed! But what this means is that when you decide not to apply DRY, you need to have a reasonable justification. Code duplication in general is a bad thing.

[StandardFuture]

Now you are shifting to a editing dilemma. Code duplication is not machine code duplication which is what really matters at execution time. Reading is also easier (even for non-Go programmers at least familiar with C) without templating-like syntax.

[nine_k]

Machine code duplication is spending a few extra megabytes on perfectly valid, if duplicate, machine code.

Source code duplication is a risk of spending an hour, or maybe a day, of developer's time to detect the duplication, change it in concert in several places, with an occasional need of detecting and fixing a subtle discrepancy between the copies.

RAM is $0.015 per megabyte. Developer time is $50 per hour.

[jesstaa]

You could also spend that developer time trying to untangle code reuse between various components, or the more subtle breakages caused by changes that don't account for the expectations of all callers. Code reuse is still a tradeoff.

[the_af]

Code duplication is definitely a programmer problem, not a machine problem. It's also a major problem. Code duplication increases the probability of programming errors, and makes maintenance harder. Any modern language with poor tools for keeping duplication at bay is suspect.

[notduncansmith]

"My editor makes it really easy to do this terrible thing, so it's okay!"

I'm sorry, I quite enjoy many aspects of Go - but the argument that committing one of the cardinal sins of programming is okay because your editor makes it easy is worse than the actual language shortcoming itself.

[sagichmal]

Code duplication is not a cardinal sin of programming. In fact, the attitude that it _is_ has probably done more harm to [modern] programming than duplication ever did :)

[nine_k]

This comment wins the thread!

Sorry, I meant to say that the language's shortcomings, even if temporary, start to attract a wrong attitude, which is sad (and you, golang team, should feel sad).

[mamcx]

OffTopic: This sync library is available?

[ufo]

Correct me if I'm wrong but doesn't the current state of affairs (using Interface{}) have all the downsides of Java's boxing but without any of the type safety?

[Pxtl]

It reminds me of the wonderful fun days of Java 1.2 - anybody remember how proud Sun was of how everything derived from object so you could use the untyped containers for everything?

[JulianMorrison]

The main difference with casting to Object is that you can use type switches or safe casts which return an additional success boolean, to restore type safety quickly after taking the item out of its container. Yes, you can type-test in Java before you type-cast, but it isn't idiomatic, and it isn't syntax.

[frowaway001]

"It's fine in Go to do the wrong thing, because they added syntax to make it even easier to do the wrong thing."

[NateDad]

The answer is not that you should use an empty interface, the answer is not to write generic functions.

[eropple]

Which leads to writing the same code repeatedly--because trying to wedge in reusability via insufficiently expressive structural typing is entertaining but often fruitless--and making the user wonder why they didn't just use something modern (setting aside stuff like Scala, even C++ can do channels, and past that the reasons for Go start vanishing real quick).

[NateDad]

I write go 40 hours a week and have been for over a year. There's been only a couple times I wanted generics and those are structures I haven't actually needed to reuse yet. I'm not guessing about not being generics much.

Edit That being said, go is not for all projects. Some projects need a lot of generics. Don't use go for that.

[eropple]

Um, I've written Go. Nontrivial amounts, as it happens. In doing so, I recognized that I was regularly forced to write worse code in the pursuit of doing things idiomatically because I lacked the semantic richness of C++, let alone Scala. And this worse-is-better attitude of the Go community gives me a dim view of its future--and between its junk GC and its completely pedestrian semantic and syntactic propositions I already had a dim view of its present.

If you write reusable, future-facing code, generic types without the erasure of interface upcasting is required. There are no two ways around it.

[NateDad]

It sounds like you were forced to write/maintain some Go code and are basing your opinion on that, an opinion heavily colored by the quality of the original code and your annoyance at your employer for making you work in something other than your preferred language(s).

It's even possible the software you were tasked with writing/maintaining was a bad fit for Go. I tried to mention that in my previous response. Such things certainly exist, and most Go enthusiasts will be more than willing to admit it.

However, saying you can't write reusable, future-facing code without generics is preposterous. To refute you, all I have to do is point you at the Go standard library. A huge body of code whose purpose is purely reuse, and not a generic to be found.

Or perhaps we could look at the thousands of reusable go packages found on godoc.org.

You don't like Go. That's a perfectly acceptable stance to take. But I don't think you've really given it a fair shake, either.

[burntsushi]

> If you write reusable, future-facing code, generic types without the erasure of interface upcasting is required.

You're entitled to your opinions, but this is a patently false statement. There is plenty of C code currently running on my machine that was written decades ago and is still actively maintained.

> And this worse-is-better attitude of the Go community gives me a dim view of its future

The Go community actively embraces Worse-Is-Better. If your opinions are well formed enough that you know you want nothing to do with it, then what is your point exactly? Yeah, you hate Go because you hate Worst-Is-Better. So what?

[EpicEng]

Well it obviously depends on what kind of code you write. People writing certain types of libraries may benefit far more from generics than you would.

[pjmlp]

> Rob Pike has outlined the tradeoffs inherent with generics here: http://research.swtch.com/2009/12/generic-dilemma.html

First of all that post was written by Russ Cox.

Second, it already has been discussed multiple times that it only focus on C++, C#, Java approaches while cleverly forgetting generics implementations exist in multiple forms since CLU (1974) introduced them.

But Go advocates take that page as dogma and toss it around every time a generics discussion comes up.

[kmontrose]

It doesn't even cover C#, just C++ and Java. C# has it's flaws certainly, but it's a baffling omission.

[pjmlp]

In the comments, where the flaws about the document are pointed out.

[kansface]

The problem is that the code that needs generics is reusable abstractions in libraries. Thats probably 1-3% of code but it is also critically important and there is no convincing workaround.

[jesstaa]

That is Russ' blog post, not Rob's.