warg VS proposal

Funcopts aren't always appropriate, but boy do they make things more readable sometimes. I use them pervasively in warg to allow declarative nested CLI commands

I wrote my own! https://github.com/bbkane/warg/

Very useful! I'll be playing with the error tree additions and studying the HTTP interface extension to see if I can replicate the pattern for https://github.com/bbkane/warg values. Id like to be able to have value-specific output for different types of --help , even ones not in warg

I'm using to allow for custom flag types in my CLI parsing library- a lot less duplicate code

One thing that I find nicer with functional options is building tree-like data structures.

My command line parsing library uses them to declaratively build CLI apps with arbitrarily nested subcommands.

Some examples at https://github.com/bbkane/warg/tree/master/examples

I'm writing a CLI parsing library, and generics have let me consolidate most of the flag value functionality for different types. So the flags for dbz --level 9000 --type superSaiyan share most of the same code even though one is an int and one is a string. So much fewer copy-paste-modify lines of code now!

This is largely what the Azure CLI does. It simplifies even further by eliminating the no-value option. Instead, you pass "true" or "false" as the value ( --example true ). It's a little more verbose but very easy to parse/write/generate. I like this convention so much I stole it for my homemade Golang CLI parsing library https://github.com/bbkane/warg/ .

The conclusion is pretty weird to me.

Go does rely on monomorphization for generics, just like C++ and Rust. The only difference is that this is an implementation detail, so Go can group multiple monomorphizations without worrying about anything else [1]. This form of hybrid monomorphization is being increasingly common, GHC does that and Rust is also trying to do so [2], so nothing special for Go here.

On the other hand, explaining variance as a lifted polymorphism is---while not incorrect per se---also weird in part because a lack of variance is at worst just an annoyance. You can always make an adopter to unify heterogeneous types. Rust calls it `Box`, Go happens to call it an interface type instead. Both languages even do not allow heterogeneous concrete (or runtime) types in a single slice! So variance has no use in both languages because no concrete types are eligible for variance anyway.

I think the conclusion got weird because the term "subtyping" is being misused. Subtyping, in the broadest sense, is just a non-trivial type relation. Many languages thus have a multiple notion of subtyping, often (almost) identical to each other but sometimes not. Go in particular has a lot of them, and even some relation like "T implements U" is a straightforward record subtyping. It is no surprise that the non-uniform value representation has the largest influence, and only monomorphization schemes and hetero-to-homogeneous adapters vary in this particular group.

[1] https://github.com/golang/proposal/blob/master/design/generi...

[2] https://rust-lang.github.io/compiler-team/working-groups/pol...

https://github.com/golang/proposal/blob/master/design/generi...

Go Team wanted generics since the start. It was always a problem implementing them without severely hurting compile time and creating compilation bloat. Rust chose to ignore this problem, by relying on LLVM backend for optimizations and dead code elimination.

Hold up, did the members actually push this forward or was support just often memed about and suddenly this proposal was made: https://github.com/golang/proposal/blob/master/design/43651-type-parameters.md

As far as I can tell, the consensus for generics was "it will happen, but we really want to get this right, and it's taking time."

I know some people did the knee-jerk attacks like "Go sucks, it should have had generics long ago" or "Go is fine, it doesn't need generics". I don't think we ever needed to take those attitudes seriously.

> Will error handling be overhauled or not?

Error handling is a thorny issue. It's the biggest complaint people have about Go, but I don't think that exceptions are obviously better, and the discriminated unions that power errors in Rust and some other languages are conspicuously absent from Go. So you end up with a bunch of different proposals for Go error handling that are either too radical or little more than syntactic sugar. The syntactic sugar proposals leave much to be desired. It looks like people are slowly grinding through these proposals until one is found with the right balance to it.

I honestly don't know what kind of changes to error handling would appear in Go 2 if/when it lands, and I think the only reasonable answer right now is "wait and find out". You can see a more reasonable proposal here:

https://github.com/golang/proposal/blob/master/design/go2dra...

Characterizing it as a "lack of vision" does not seem fair here--I started using Rust back in the days when boxed pointers had ~ on them, and it seemed like it took Rust a lot of iterations to get to the current design. Which is fine. I am also never quite sure what is going to get added to future versions of C#.

I am also not quite sure why Go gets so much hate on Hacker News--as far as I can tell, people have more or less given up on criticizing Java and C# (it's not like they've ossified), and C++ is enough of a dumpster fire that it seems gauche to point it out.

There will almost certainly not be a Go 2 in that sense. There is a Go 2 transition doc which extensively discusses what "Go 2" means. The conclusion is

As it says on that page - those were not proposals. They were draft ideas to get feedback on. You can see the list of proposals in this repository: https://github.com/golang/proposal

Approximately a year ago we faced with a necessity of limiting Go runtime memory consumption and started work on our own memory limiter. At the same time, Michael Knyszek published his well-known proposal. Now we have our own implementation quite similar to what has been released in 1.18, but there are two key differences: