[ziotom78]

Not the OP, but here are my 2¢. Introducing generics in a language implies a deep revision of the type system, which risks to become much more complex to understand. Moreover, this might have a bad impact on compilation performance (compare C++ compilation times with Go compilation times and you'll understand what I mean).

[peoplewindow]

C++ compile times are huge for many reasons, but templates are only one of them. And note that templates aren't the same thing as generics.

Java has near-instant compile times and has generics. Likewise for Kotlin. Generics don't have to mean slow compiles.

[frankzinger]

It sounds like you're saying Java's generics are somehow superior to C++ templates.

For those who don't know, C++ generates a separate instance of the code for each type which means that it can operate directly on a value instead of through a reference/pointer and it also makes it possible for the compiler to inline the type-specific code in many cases. Ie., it has the potential to be much more efficient. That is why it works the way it does. The downside is that the code generation slows down compile times, as you noted.

Java simply casts a reference to an instance of Object to the type on behalf of the user. So you effectively have generic code the way it's done in C (void*) and Go (interface{}) but without the explicit casts.

Maybe the JIT offsets many of these inefficiencies but making that comparison is beyond me. I only bring this up because you made it sound like Java got generics completely right and C++ got it all wrong, and with the amount of flak C++ gets these days I think it deserves a little help now and then.

[peoplewindow]

I didn't intend it to come across like that. C++ is how you have to do aggressive type specialisations and optimisations in the absence of a JITC. Java's JITC is able to do many of the same things at runtime as C++ does at compile time, but it's less predictable.

[ziotom78]

I was not referring to templates only, but to the overall complexity of the C++ language. Examples: syntactic ambiguities, the preprocessor... Templates are a big part of the problem, but not the only one for sure. Languages like Free Pascal have outstanding compilation times because they privileged language simplicity, and IMHO Go falls in the same ballpark.