A year ago we said it was time to move toward Go 2: https://blog.golang.org/toward-go2 . This is another step in that direction.

Then I'm a year late in asking why the Go team is now deciding to say yes to something they said no to for over half a decade.

The blog post explains that.

Nothing changed. It wasn't off the table to begin with. See: https://golang.org/doc/faq#generics

The question of the parent boils down to "what put it on the menu".

So, yeah, it was always "on the table" in some hazy, we'll see later, way, but not like that.

I think a good faith reading of the circumstance would lead one to conclude that the passage of time, and other, higher-priority and lower-cost-of-implementation issues being addressed, have put these issues on the menu.

Likely because they have now figured out implementations of these features which they feel work well with the rest of the language design.

Because now is later than when they said later?

The reason for saying "no, but maybe later" originally was that it was always a desired piece of functionality. I believe the word "inevitable" was even tossed around. The problem was that they didn't like the existing implementations of generics in other languages and also didn't know how they would improve it. I haven't had time to look at the details, so I'm not sure what they actually did, but I think they basically came up with a strategy that they are mostly happy with.

You might ask, why not pick a solution earlier and then improve it over time? However with a popular language it's not that easy. People are writing lots of code. If you start early, you can paint yourself in a corner and end up with a system that you really can't improve very much because it introduces incompatible changes. Note the extremely painful (and drawn out!) incompatible changes with Perl 6 and Python 3. If you make the wrong choice early, you might still take over a decade to find an opportunity to replace it. And since the state of the art in language design moves very slowly, it took a long time before they could see something that they felt they wouldn't regret choosing.

I highly recommend reading https://go.googlesource.com/proposal/+/master/design/go2draf...

This is part of the material linked to from this thread. It answers all your questions. You will see that some of the people who are directly replying to you are very much involved in this effort.

Edit: I tried editing the previous message but HN actually automatically made a reply instead....

Adding generics is a major change (e.g. it would restructure the stdlib), and so it would only belong in a major-version bump of the language.

Though the authors have clarified that the "2" in "Go 2" is just for marketing purposes, and that the actual release would still be "Go 1.x", and shouldn't break any existing code (so it won't restructure the stdlib in any major way, unless they want to do a huge mass-deprecation).

So Go is following the exact same path as Java.

Inevitably.

Also inevitably, Java will get value types (structs) at some point.

Just like with Go Generics, people will complain the feature is bolted on. After some time it is just one of the many quirks of a complex language.

I think it was Stroustrup who said: there are two kinds of programming languages, the ones people hate and the ones nobody uses.

And Java had quite a few good examples to take on like Modula-3 and Eiffel, but alas they wanted something for average Joe, kind of sounds familiar.

The difference is that Go could have learned from Java.

I think because it would break backward compatability in v1, and not doing that was the Most Important Thing in all 1.xx releases.

v2 is allowed to Break Stuff. So obviously they're going to consider the thing that people have shouted for most in Go... generics and error handling (and package management but they found a way of doing that earlier).

> What changed? Why is the Go team finally considering this now, when it has been requested for these exact reasons by many credible developers since Go's beginning?

Simply, Go has probably accumulated all the developers it is going to accumulate without something drastically changing.

At this point, I can't think of any programmers around me who now want to learn Go.