proposal
RE2
proposal | RE2 | |
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46 | 49 | |
3,290 | 8,628 | |
0.4% | 0.6% | |
4.4 | 8.9 | |
about 2 months ago | 5 days ago | |
Go | C++ | |
BSD 3-clause "New" or "Revised" License | BSD 3-clause "New" or "Revised" License |
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proposal
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Does Go Have Subtyping?
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...
- Backward Compatibility, Go 1.21, and Go 2
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Defining interfaces in C++ with ‘concepts’ (C++20)
https://github.com/golang/proposal/blob/master/design/generi...
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Why Turborepo is migrating from Go to Rust – Vercel
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.
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Are you a real programmer if you use VS Code? No Says OP in the byte sized drama
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
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Major standard library changes in Go 1.20
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.
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Go's Future v2 and Go's Versioning
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
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What's the status of the various "Go 2" proposals?
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
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An alternative memory limiter for Go based on GC tuning and request throttling
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:
- Shaving 40% off Google’s B-Tree Implementation with Go Generics
RE2
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C Is the Greenest Programming Language
Looking at the benchmark where C++ is worst compared to other languages, it's depending on the library used. I would guess if they used Google's re2 Regex library instead of Boost's, the result would be different.
https://github.com/google/re2
https://github.com/greensoftwarelab/Energy-Languages/blob/ma...
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what does this + do in the regular expression "(^A-Za-z)+"
That page says it just includes "some of the most common special characters", and following the link to the Examples page in turn includes a link to the full list.
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On a Great Interview Question
Python uses backtracking, so this probably isn't O(n), especially with the ability to choose the dictionary.
But with there are non-backtracking matchers which would make this O(n). Here's re2 from https://github.com/google/re2 :
>>> import re2
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RE2 VS hyperscan - a user suggested alternative
2 projects | 17 Mar 2023
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hyperscan VS RE2 - a user suggested alternative
2 projects | 17 Mar 2023
RE2 is a Google regular expression library
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Projects ideas to learn C++/OOP
google's regex library: https://github.com/google/re2
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Regex: is there a difference between * and {0,}, as well as + and {1,}?
I am currently working with Regex, specifically Re2, and was wondering if there is a real difference between the above expressions for repeated sub-regex.
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First release of SPVM::File::Spec - complex regular expressions, file tests, SPVM::Cwd, inheritance
I ported Google RE2, a regular expression library, to SPVM as Resource::Re2, and created SPVM::Regex, a wrapper for it.
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SPVM::File::Basename is released. This is the first module of SPVM using regular expressions.
I searched for I found that there is a Perl compatible regular expression called Google RE2. It is written in C++, and with Google RE2, I can use Perl-compatible regular expressions as a library.
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Ruby 3.2.0 Is from Another Dimension
Yes, but there is an interesting clarification here. RE2 has used the "caching" approach documented in the Ruby bug ticket linked for quite some time (since its birth?): https://github.com/google/re2/blob/954656f47fe8fb505d4818da1...
It is mentioned only briefly in Cox's article on regex matching in the wild. Look for the word "bitstate": https://swtch.com/~rsc/regexp/regexp3.html
I didn't know Perl had implemented this trick too.
The paper[1] cited in the Ruby bug ticket was published very recently. When I first read the Ruby bug ticket, I immediately wondered how they sidestepped the memory use problem. The paper's abstract seems to suggest there is some technique for doing so, as it rebuffs the idea of doing "full" memoization. Alas, I do not have access the paper. (Which is fucking ridiculous.)
[1]: https://ieeexplore.ieee.org/abstract/document/9519427
What are some alternatives?
go - The Go programming language
compile-time-regular-expressions - Compile Time Regular Expression in C++
vscode-gremlins - Gremlins tracker for Visual Studio Code: reveals invisible whitespace and other annoying characters
semver.c - Semantic version in ANSI C
avendish - declarative polyamorous cross-system intermedia objects
Boost.Signals - Boost.org signals2 module
too-many-lists - Learn Rust by writing Entirely Too Many linked lists
libevil - The Evil License Manager
go-generic-optional - Implementation of Optionals in Go using Generics
constexpr-8cc - Compile-time C Compiler implemented as C++14 constant expressions
go_chainable - With generics, allowing chainable .Map(func(...)).Reduce(func(...)) syntax in go
Cppcheck - static analysis of C/C++ code