423dc155d8
Summary: X-link: https://github.com/facebook/react-native/pull/38303 Pull Request resolved: https://github.com/facebook/yoga/pull/1327 This bumps Yoga to C++ 17 for a few reasons: 1. New versions of C++ may introduce behavior changes (e.g. evaluation order) and deprecations. Keeping the version closer to the version of large users helps avoid that. 2. C++ 17 unblocks some new bits I have wanted to use at times, like `std::optional`, `std::variant`, `if constexpr`, `[[nodiscard]]`. 3. There are already changes in C++ 20 that would be directly useful to Yoga, like `std::bit_cast` to avoid `memcpy` style type punning. There has been some contention around C++ versions before, but by the time the next stable version of Yoga is out, it will have been more than 6 years (~2 C++ versions) since a stable version of Clang/LLVM with C++ 17 support. I would not like to go back further than n-2. Changelog: [Internal] Reviewed By: christophpurrer Differential Revision: D47383922 fbshipit-source-id: eb95d4853f2168b68d6df5fddb797236eac55870
37 lines
1.9 KiB
Markdown
37 lines
1.9 KiB
Markdown
# Yoga [](https://opensource.fb.com/support-ukraine) [](http://cocoapods.org/pods/YogaKit) [](https://www.npmjs.com/package/yoga-layout) [](https://search.maven.org/artifact/com.facebook.yoga/yoga)
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Yoga is an embeddable and performant flexbox layout engine with bindings for multiple languages.
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## Building
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Yoga's main implementation targets C++ 17 with accompanying build logic in CMake. A wrapper is provided to build the main library and run unit tests.
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```sh
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./unit_tests <Debug|Release>
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```
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While not required, this script will use [ninja](https://ninja-build.org/) if it is installed for faster builds.
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Yoga is additionally part of the [vcpkg](https://github.com/Microsoft/vcpkg/) collection of ports maintained by Microsoft and community contributors. If the version is out of date, please [create an issue or pull request](https://github.com/Microsoft/vcpkg) on the vcpkg repository.
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## Adding Tests
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Many of Yoga's tests are automatically generated, using HTML fixtures describing node structure. These are rendered in Chrome to generate an expected layout result for the tree. New fixtures can be added to `gentest/fixtures`.
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```html
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<div id="my_test" style="width: 100px; height: 100px; align-items: center;">
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<div style="width: 50px; height: 50px;"></div>
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</div>
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```
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To generate new tests from added fixtures:
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1. Run `bundle install` in the `gentest` directory to install dependencies of the test generator.
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2. Run `ruby gentest.rb` in the `gentest` directory.
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## Debugging
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Yoga provides a VSCode "launch.json" configuration which allows debugging unit tests. Simply add your breakpoints, and run "Debug C++ Unit tests (lldb)" (or "Debug C++ Unit tests (vsdbg)" on Windows).
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