I'm pretty sure the feature will show up in the next few minor version increments.
No it won't. People need to stop expecting generics because it will never happen. Not that agree with this but it was made pretty clear in the go-nuts mailing list that the Go team wants to keep Go type system "simple".
We just came out of a decade of nifty language mania. What I learned is that languages are boring but problems are interesting. Algorithms and solutions are interesting. A great solution to a challenging problem is really interesting even if it's in the most boring language ever.
I have code on my machine written in C in the 70s because C is largely "done." People today continue to write interesting stuff in C. Neuromancer was written in the same language as Lord of the Rings and Moby Dick, too.
Of course, we're talking about pre-ANSI C where any function prototype without a void argument implicitly accepts any and all arguments.
I don't think Go is done. The active development speaks otherwise.
But working at a price. And Go isn't willing to pay the price (especially in terms of compile time). If Go ever adds generics, it will be with a new approach that doesn't blow up compile times.
IIRC the reasons on the list were the standard tradeoffs of memory space and so on. Do they emit specialized versions for each function, or not, and so on. Again, stuff that's working fine in other platforms.
Developer time costs more than compiler time.
I find that to be a very odd statement. Usually, the developer waits for the compiler in order to find out if the code compiles and executes properly. That is, every minute of compiler time costs a minute of developer time.
Worse, the developer time you spend due to lack of a feature, you spend while writing some code that would benefit from the feature. The compiler time you pay every time you compile - year after year, for some projects.
If your business starts to hit a wall on compile times you can buy a computer that can compile twice as fast. It's much harder to buy a developer who can think twice as fast. And every year the computers get faster and the developers stay the same.
> Worse, the developer time you spend due to lack of a feature, you spend while writing some code that would benefit from the feature. The compiler time you pay every time you compile - year after year, for some projects.
No, the cost of being unable to abstract increases exponentially as your system grows. If using language X lets you cut 500 lines from a 1000-line Go project, then when you have a 2000-line Go project, in language X you'd be able to cut 500 lines from each half of it considering each half in isolation - and then you'd be able to cut some more because of things that were common between the two halves - so you'd end up with just 750 lines of language X. And you pay the cost of extra lines every time you read or debug, year after year.
Buying a fast machine only gets you so far. Large C++ projects take minutes to compile even on the fastest machines available. Plus, you'd need to buy one for every developer.
> when you have a 2000-line Go project, in language X you'd be able to cut 500 lines from each half of it considering each half in isolation - and then you'd be able to cut some more because of things that were common between the two halves - so you'd end up with just 750 lines of language X.
While this is true in theory, in practice I think the effect is not quite as large. As the project grows, developers take ownership of certain parts of the code and become ignorant of other parts. This is the whole point of abstraction. Under these conditions it will take a heavy investment of time and effort to find and replace the things in common between the two halves. So you might cut 250 lines in common between two 1000-line halves, but you're not going to cut 25,000 lines in common between two 100,000-line halves without a serious amount of work.
I think Go's design shows awareness of this effect. The Go literature does not preach the battle against code duplication as strongly as, say, Java. The goal is to make it easy to understand the other team's 100,000 lines, even if that comes at the expense of some code duplication.
Note: I am not a Go programmer, but I do think that optimizing for ``code entropy'' (lack of duplicated code) over all else is a mistake.
Maybe. I find the same patterns tend to show up in a lot of code, so very high-level libraries like scalaz or recursion-schemes (that you can't even think without a powerful type system) turn out to save code virtually everywhere.
> Note: I am not a Go programmer, but I do think that optimizing for ``code entropy'' (lack of duplicated code) over all else is a mistake.
Intuitively it does seem like other things should be more important, but I've become more attached to that measure through experience. Even seemingly innocuous duplication tends to go wrong over time.
In some cases, if you have long-lived services, then Java and .Net make sense... You can get farther with the code in place. If you are running one-off executable handlers, that need to start and finish quickly, then you probably would favor go.
It's entirely possible for different options to be part of a larger solution.. and while I agree, the lack of generics is truly painful... I remember C# before, and feel that Java's generics are a horrible implementation... I'd rather wait for a nice implementation just the same.
And I doubt generics make a significant difference in runtime but I don't have a CLR v1.1 around to test it out. For comparison, a C# hello world takes about 10ms longer than a C one (both compiled with optimizations; .NET 4.6 C# 6 / MSVC 19) on my i5 Broadwell laptop. Timing as measured by "time" in bash (~25ms vs ~35ms).
I'm guessing you're talking about JIT in general and of course have a point there. I doubt it's significant for any significant values of significant.
I remember the difference being a bit more than that, on the order of half a second in difference.. but that was around the .Net 1.0 timeframe.. I still used it for a lot of things because it didn't matter to me.. but a couple of things I wanted to use it for at the time was too much lag for starting an EXE and getting output from the command prompt.. running as a service was a different story.
A 1.2Ghz early Athlon was a lot slower than what we have today as well... even so, depending on what you need, even 10ms can make a difference.
Except that this is a false dichotomy: you don't have to have a lack of features to get a fast compile. Incremental compiles have existed for a very long time in various language ecosystems and will achieve very acceptable results.
In addition, SSDs and multicore CPUs can be leveraged to decrease compile times, and these things are only getting better.
The bigger problem is that Go doesn't have type inheritance or similar. Meaning, there's no great way to say that this generic function will only work with number types, for example. You leave the burden on the programmer to ensure their generalized function is applied only to types which it is intended to be used with.
While that is less than ideal, I cannot see that increasing developer time by a significant margin.
I'll stop you right there. Have you seen a modern Go codebase?
They most certainly duplicate the simplest of functions, resort to `go generate`, or use reflection.
I _think_ what you are trying to say is that templates in Go are less convenient than in some other languages. That is a completely fair assertion. But the idea of having to type `go generate` occasionally adding significant man hours to a project seems a little far fetched. You could even:
alias go='go generate && go'
That's besides the point, codegen from extra on-disk files can only be slower than codegen without extra on-disk files, so "generics are slow to compile" and "go has generate" don't make sense together, yet they are used together to assert that generics are bad and anyway go has a replacement.
> go's build system handles these sort of things without a more complex workflow.
No they don't. If you're using go generate you have to run go generate. That's a strictly more complex workflow than not having to run it.
While I agree that "strictly" your assessment is corect it's more complex, I think you're being a bit literal; it's just another command. most of my builds have hundreds of commands.
Go is only unique in that it can do a complete recompile in very attractive times. The only hitch, of course, is that you sacrifice features known and loved in other languages for over a decade.