frunk
tlaplus
frunk | tlaplus | |
---|---|---|
7 | 38 | |
1,199 | 2,210 | |
- | 0.8% | |
5.9 | 9.1 | |
3 months ago | 6 days ago | |
Rust | Java | |
MIT License | MIT License |
Stars - the number of stars that a project has on GitHub. Growth - month over month growth in stars.
Activity is a relative number indicating how actively a project is being developed. Recent commits have higher weight than older ones.
For example, an activity of 9.0 indicates that a project is amongst the top 10% of the most actively developed projects that we are tracking.
frunk
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Apply generic function to every tuple element
So rust doesn't support variadics, but I have heard some murmurings around the topic. In the meantime, you can still do a lot with recursive tras. The frunk crate makes working with them a lot easier: In this case
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Self Referencing structs with different generic types
I think the closest possible approach is the one used in frunk where those consecutive types are nested recursively (creating a linked list on type level basically) and special type is used as the end.
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Is there a convenient way to convert a struct<T> (where all fields are of type T) into struct<U> where U: From<T>?
I suggest looking into frunk. You could convert the struct into an HList, map over the values to convert and convert into the target struct. README has some relevant examples.
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Can we make useful streaming APIs that disallow deadlocks?
So a while back I got interested in how rust could provide parallel/concurrent APIs that prevent deadlocking shared state. I now created a Proof-of-Concept stream processing library that attempts to do that. The library makes prodigious use of heterogeneous lists from the frunk library. The basic idea is that you can build a graph by combining source streams as source nodes and mutexes for state, then you can add nodes which subscribe to subsets of the previous nodes using various combinators. You can either
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constduck: compile-time duck typing and reflection powered by const generics
Hey, #[derive(LabelledGeneric)] from frunk does something like this, but without const generics, so it has odd representations for things like type-level strings (it's represented as a tuple of chars so (a, b, c) is the type-level representation of the string "abc")
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Symbolics.jl: A Modern Computer Algebra System for a Modern Language
I don't understand why you call it "trickery or "fake". Church encoding of natural numbers is the same technique used in Agda, Coq and Idris to represent the Peano numbers. It's a completely valid encoding and isomorphic to any other representation.
You don't need to use a fixed-length array either - you can used a recursive linked list at the type-level for an unbounded encoding [1]. The Scala library is an example of that; the Github page even has an example of encoding arbitrary units like sheep and wheat.
[1] https://github.com/lloydmeta/frunk
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Generic associated types encode higher-order functions on types
I wonder if frunk can (ab)use this kind of trick to make their crate even more powerful. IIRC they have a bunch of amazing and horrible workarounds to work with type-level lists.
tlaplus
- Ask HN: Usefulness of formal verification (Coq) and formal verification (TLA+)?
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Quint: A specification language based on the temporal logic of actions (TLA)
```
https://github.com/tlaplus/tlaplus/blob/master/tlatools/org....
In any case, our whole team thinks TLA is great, and we're happy people like you and Ron find it so useful and insightful. We also think it is a very insightful.
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Concurrent Data-structure Design Walk-Through
There are no tests! There are various ways to test concurrent data structures. You could use a stress test, where you spawn a lot of threads and let them mutate the map in a random way and then check the consistency of the map and some invariants. You could learn TLA+ and write a formal model of the map and then verify it.
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In Which I Claim Rich Hickey Is Wrong
Dafny and Whiley are two examples with explicit verification support. Idris and other dependently typed languages should all be rich enough to express the required predicate but might not necessarily be able to accept a reasonable implementation as proof. Isabelle, Lean, Coq, and other theorem provers definitely can express the capability but aren't going to churn out much in the way of executable programs; they're more useful to guide an implementation in a more practical functional language but then the proof is separated from the implementation, and you could also use tools like TLA+.
https://dafny.org/
https://whiley.org/
https://www.idris-lang.org/
https://isabelle.in.tum.de/
https://leanprover.github.io/
https://coq.inria.fr/
http://lamport.azurewebsites.net/tla/tla.html
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Programming Languages Going Above and Beyond
I wish something like Lamport's TLA+ (https://lamport.azurewebsites.net/tla/tla.html) was supported in modern language compilers - perhaps with annotations/macros and a mini formal DSL.
- Ask HN: How you understand TLA+ and how you use TLA+ in your projects?
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A collection of lock-free data structures written in standard C++11
Checking the invariant with assert is also useful in my limited experience with concurrency.
https://lamport.azurewebsites.net/tla/tla.html
- Ask HN: Is writing a math proof like programming without ever running your code?
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What I've Learned About Formal Methods in Half a Year
One advantage of formal methods is in determining "what was expected" (including all the goofy edge cases) without having to burrow into the details of code.
Take a look at Alloy (http://alloytools.org/) and TLA+ (https://lamport.azurewebsites.net/tla/tla.html) for example. (Or even the ancient Z ("Zed") notation (https://www.cs.cmu.edu/~15819/zedbook.pdf)).
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How do I get the set of process identifier of PlusCal?
The pcal generator does *not* generate a definition for the set of labels. However, some users have suggested to add such a feature: https://github.com/tlaplus/tlaplus/issues/613
What are some alternatives?
tyrade - A pure functional language for type-level programming in Rust
dafny - Dafny is a verification-aware programming language
stately-streams - combine mutable state and asynchronous streams without deadlocks
coq - Coq is a formal proof management system. It provides a formal language to write mathematical definitions, executable algorithms and theorems together with an environment for semi-interactive development of machine-checked proofs.
sicmutils - Computer Algebra, Physics and Differential Geometry in Clojure.
apalache - APALACHE: symbolic model checker for TLA+ and Quint
scroll - Scroll - making scrolling through buffers fun since 2016
stateright - A model checker for implementing distributed systems.
Algebird - Abstract Algebra for Scala
awesome-programming-languages - The list of an awesome programming languages that you might be interested in
typic - Type-safe transmutations between layout-compatible types.
adventofcode - Advent of Code solutions of 2015, 2016, 2017, 2018, 2019, 2020, 2021, 2022 and 2023 in Scala