alive2
Cassius
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alive2 | Cassius | |
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4 | 5 | |
667 | 90 | |
4.3% | - | |
9.3 | 0.0 | |
11 days ago | about 1 year ago | |
C++ | Racket | |
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.
alive2
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Basic SAT model of x86 instructions using Z3, autogenerated from Intel docs
You can use it to (mostly) validate small snippets are the same. See Alive2 for the application of Z3/formalization of programs as SMT for that [1]. As far as I'm aware there are some problems scaling up to arbitrarily sized programs due to a lack of formalization in higher level languages in addition to computational constraints. With a lot of time and effort it can be done though [2].
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Verifying GCC optimizations using an SMT solver
Yeah, this kind of thing is nice.
Alive had been used for years (almost a decade actually) by people to verify LLVM instcombine transforms.
Alive2 (https://github.com/AliveToolkit/alive2) makes it easier to do the same with most optimization passes.
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Programming in Z3 by learning to think like a compiler
Alive/Alive2 [1] is one of the most famous frameworks for compiler transformation verification using BitVec logic
Cassius
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The Rules of Margin Collapse
FWIW, while there are unfortunately only very few attempts at formalizing CSS, there's at least an unofficial, unreviewed (?), partial formal semantics for (CSS 2-era) float layout based on z3 SMT and Racket you can take a look at to get a flavor, though it isn't receiving further development.
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W3Cβs transfer from MIT to non-profit going poorly
Do we need W3C anymore? The HTML 5 specification has been created by WHATWG for many years now, with W3C only rubber-stamping historic WHATWG versions until 2017 or so. SVG2 is going nowhere, and so isn't MathML, leaving the CSS working group as W3C's remaining point of influence over the Web. CSS is regarded as so poor and overdone a specification that the only two external projects for a formal specification have failed or remained woefully incomplete (1, 2).
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Is There Too Much CSS Now?
1. CSS should've been split into app-y styles and doc-y styles a looong time ago; meaning that when you need JavaScript to make use of a feature anyway, there's no point in using CSS and it's better to set styles, layout using JavaScript rather than bloat CSS. The Houdini API was on the right track years ago.
2. The CSS WG at W3C must deliver formal specification rather than the prose they're writing up now. For an idea how a (partial) formal spec for CSS rendering looks like, see eg. [1], [2] (with limitations).
The one way complexity that both W3C and WHATWG have delivered over the past 15 years with complete lack of mental discipline due to financial dependency/job security will be a major source of confusion for generations to cone, and will not be looked at favorably.
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Verifying GCC optimizations using an SMT solver
There's this cool project using z3 (and racket) for formalizing CSS rendering [1] I never came around to lift for anything. Maybe someone else interested in leading the web out of the dark ages and give W3C's CSS WG an idea what we expect from them will.
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Ladybird: A new cross-platform browser project
FWIW, I know two (partial, kinda) formal specifications of CSS normal flow and float layout, both of which are finished ie dead projects:
[1]: https://lmeyerov.github.io/projects/pbrowser/pubfiles/paper....
[2]: https://github.com/uwplse/cassius
(not counting the 1990s constraint CSS effort).
The first was merely part of a parallel compiler project and also covers table layout, whereas the second is a Racket (Scheme) program to formulate the HTML doc and CSS rules as a theory for submitting to z3 SMT to solve all kinds of decision problems (it can also produce a rendering).
Not sure that's very helpful; it would be cool if W3C can invest some time into better specs (not just prose).
What are some alternatives?
CrossHair - An analysis tool for Python that blurs the line between testing and type systems.
Radpath - Path library for Elixir inspired by Python's pathlib
klee - KLEE Symbolic Execution Engine
ex_guard - ExGuard is a mix command to handle events on file system modifications
zz - πΊπ ZetZ a zymbolic verifier and tranzpiler to bare metal C
recreational-rosette - Some fun examples of solving problems with symbolic execution
Symbolica - Symbolica's open-source symbolic execution engine. [Moved to: https://github.com/Symbolica/Symbolica]
sizeable - An Elixir library to make File Sizes human-readable
llvm-tutor - A collection of out-of-tree LLVM passes for teaching and learning
servo-embedding-example - Examples of embedding Servo inside non-browser GL applications.
taxoptimizer
sprdpl - Simple Python Recursive-Descent Parsing Library