tlaplus
apalache
Our great sponsors
tlaplus | apalache | |
---|---|---|
38 | 6 | |
2,201 | 409 | |
1.2% | 4.9% | |
9.1 | 9.5 | |
8 days ago | 7 days ago | |
Java | Scala | |
MIT License | Apache License 2.0 |
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.
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)
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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
apalache
- Holiday protocols: secret Santa with Quint
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Learn TLA+
Anyone know of some good free software TLA+ model checkers? The "Other Tooling" mentions one alternative checker, https://apalache.informal.systems/, but that's all I could find. Thanks.
- Apalache – Symbolic Model Checker for TLA+
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A dependently typed language for proofs that you can implement in one day
> How are those types any different than outright stating a behavioral invariant?
Because the behavior of programs can't be verified without executing the program, but types can be checked purely based on syntax. There is way less source code than runtime states of any non-trivial program.
I've asked this same question many times, the TLA+ way is much more expressive and _simpler_. But model checking is a way harder problem than type checking, in general. SMT solvers make this line blurry - in fact, have you heard of the SMT-based model checker for TLA+, [Apalache](https://apalache.informal.systems/)?. I haven't tried it out, but that should be way faster than TLC which just brute forces the state-space exploration.
I'm totally with you about TLA+ style spec properties, but it's a big theoretical hurdle to cross before they could be as efficient as types.
- Apalache Release v0.15.1
- Apalache, a symbolic model checker for TLA+, v0.8.0 is released
What are some alternatives?
dafny - Dafny is a verification-aware programming language
Formality - A modern proof language [Moved to: https://github.com/kind-lang/Kind]
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.
advent-of-tla - AoC goals in TLA+
stateright - A model checker for implementing distributed systems.
BlockingQueue - Tutorial "Weeks of debugging can save you hours of TLA+". Each git commit introduces a new concept => check the git history!
awesome-programming-languages - The list of an awesome programming languages that you might be interested in
ewd998 - Distributed termination detection on a ring, due to Shmuel Safra:
adventofcode - Advent of Code solutions of 2015, 2016, 2017, 2018, 2019, 2020, 2021, 2022 and 2023 in Scala
suslik - Synthesis of Heap-Manipulating Programs from Separation Logic
Corinna - Corinna - Bring Modern OO to the Core of Perl
PomPom-Language - The cuteness implementation of a dependently typed language.