go's version of interfaces is fairly unique, if you read that as them inventing interfaces you misread. If you read it as them having a unique twist on interfaces they felt was powerful, then you read it correctly.
It never even occurred to me that someone would suggest they're claiming to have invented interfaces, mostly because obviously they didn't.
I was careful to try read what was said; the language might be a bit loose because it's a transcript of a live talk. That said, the example they gave, and their motivating problem of the qsort API in C don't show anything about using nominal interfaces, and instead look like a normal use of interfaces, combined with language about being wowed of how powerful they could be.
> It's clear that interfaces are, with concurrency, a distinguishing idea in Go. They are Go's answer to objected-oriented design, in the original, behavior-focused style, despite a continuing push by newcomers to make structs carry that load.
> Making interfaces dynamic, with no need to announce ahead of time which types implement them, bothered some early critics, and still irritates a few, but it's important to the style of programming that Go fostered. Much of the standard library is built upon their foundation, and broader subjects such as testing and managing dependencies rely heavily on their generous, "all are welcome" nature.
> I feel that interfaces are one of the best-designed things in Go.
> Other than a few early conversations about whether data should be included in their definition, they arrived fully formed on literally the first day of discussions.
> And there is a story to tell there.
> On that famous first day in Robert's and my office, we asked the question of what to do about polymorphism. Ken and I knew from C that qsort could serve as a difficult test case, so the three of us started to talk about how our embryonic language could implement a type-safe sort routine.
> Robert and I came up with the same idea pretty much simultaneously: using methods on types to provide the operations that sort needed. That notion quickly grew into the idea that value types had behaviors, defined as methods, and that sets of methods could provide interfaces that functions could operate on. Go's interfaces arose pretty much right away.
> That's something that is not often not acknowledged: Go's sort is implemented as a function that operates on an interface. This is not the style of object-oriented programming most people were familiar with, but it's a very powerful idea.
> That idea was exciting for us, and the possibility that this could become a foundational
> programming construct was intoxicating. When Russ joined, he soon pointed out how I/O would fit beautifully into this idea, and the library took place rapidly, based in large part on the three famous interfaces: empty, Writer, and Reader, holding an average of two thirds of a method each. Those tiny methods are idiomatic to Go, and ubiquitous.
> _THE WAY INTERFACES WORKED became not only a distinguishing feature of Go, they became the way we thought about libraries, and generality, and composition. It was heady stuff.
emphasis at the end there is mine.
how the hell _anyone_ reads that and comes away with the idea that they're claiming they invented the idea of interfaces is beyond me.
my only guess here is that many people are not familiar with the sort problem they're describing.
very famously, C++'s sort is more performant than C's sort because C uses a void pointer and C++ uses templates. The extra type information allows C++ to optimize the sort in a way that C cannot, so while C is generally more performant than C++ in a lot of ways, this is one particular area where C++ shines.
So it's no surprise that Rob Pike, et al, paid close attention to sort as something to improve over C and the way to do that is having more type information available (C++ very clearly has shown this).
> That's something that is not often not acknowledged: Go's sort is implemented as a function that operates on an interface. This is not the style of object-oriented programming most people were familiar with, but it's a very powerful idea.
I feel like most of this is just ignoring the prior art. C#'s sort works the same way. Admittedly, this isn't obvious because of the way it's implemented. But if you're a language designer you don't have much of an excuse there.
> Robert and I came up with the same idea pretty much simultaneously: using methods on types to provide the operations that sort needed. That notion quickly grew into the idea that value types had behaviors, defined as methods, and that sets of methods could provide interfaces that functions could operate on. Go's interfaces arose pretty much right away.
> That's something that is not often not acknowledged: Go's sort is implemented as a function that operates on an interface. This is not the style of object-oriented programming most people were familiar with, but it's a very powerful idea.
What he actually said is that being able to pass a value type into a sort function and have it work without needing to explicitly define and implement an interface was not a style that most people are familiar with.
and indeed, C# absolutely does NOT work that way.
It probably would have been better for you to claim that Ruby had prior art, but even that's implemented in an entirely different way it's just that the behavior is closer to Go's behavior than C# is.
In his defence, their interfaces do work somewhat differently to Java's, because they don't need to be explicitly implemented. I don't know if that matters enough to make them a novel invention, though.
It sounded like it to me. I kept thinking didn't java have interfaces to prevent multiple inheritance? All go did was replace all inheritance with interfaces
Go's concurrency isn't even that good. It just looks good for anyone coming from the languages which don't have that (which are the majority).
One of the earliest high level languages with powerful concurrency and parallelism APIs are C# and F# (TPL and Parallel/PLINQ, some of which was available back in 2010).
They are certainly different, but to say there is nothing similar is plainly untrue - apart from nominal vs structural, they are pretty much the same.
I'm not sure how significant the nominal vs structural distinction even is. In Go, a struct can implement an interface without declaring it, but the programmer still needs to deliberately write the struct to conform to the definition of the interface, so they're still coupled, just not explicitly [1]. Yes, it is possible to define a new interface which fits existing structs which weren't designed for it - but how common is that? That is, how common is it for two or more structs to have a meaningful overlapping set of methods without being designed to conform to some pre-existing interface?
Go's nominal interface feature is definitely interesting, but that section doesn't talk about how amazing it was to implement interfaces implicitly:
> That notion quickly grew into the idea that value types had behaviors, defined as methods, and that sets of methods could provide interfaces that functions could operate on. Go's interfaces arose pretty much right away.
If you replace Go with Java, this would've accurately described Java ~30 years ago.
As the review Chen links discusses, it turns out that M:N threading (i.e. goroutines) and good C compatibility are mutually exclusive. Go went one way, every other language went the other way. The most common alternative is stackless coroutines, which are much more widely implemented than the Go model.
To the extent that Go has features that no other popular language has, it is not influential. To the extent to which it invented those things, it's not influential. And that's why he didn't make that claim, he made a much broader one. The only problem is, if you make the broader one, it's obvious it's F#/C# that's been influential.
Erlang's processes might have similar semantics to Go's goroutines (green threads) but Erlang is a much simpler language, because it doesn't have shared state.
A lot of work went into optimizing Go's GC to be able to cope with concurrency.
