Reflection tutorial - #146
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RyanJK5
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Really happy with how this came out. It keeps the relevant parts of reflection in clear focus.
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| // We use `throw` inside a `consteval` block rather than `static_assert` | ||
| // or `EXPECT_*`: `static_assert` needs `members` to independently be a | ||
| // constant expression, and `EXPECT_*`'s comparison helpers aren't | ||
| // `constexpr` functions. |
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This could probably do with a one-sentence explanation of what a consteval block is.
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| TEST(TutorialsReflection, Substitute) { | ||
| // `substitute(^^Template, {args...})` instantiates a template from infos; | ||
| // `reflect_constant` turns an ordinary value into an info usable as a | ||
| // non-type template argument. | ||
| // clang-format off | ||
| constexpr std::meta::info array_info = | ||
| substitute(^^std::array, {^^double, std::meta::reflect_constant(3)}); | ||
| // clang-format on | ||
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| static_assert(std::is_same_v<typename[:array_info:], std::array<double, 3>>); | ||
| } |
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I think this could benefit from a comment explaining the use case of substitute - when you want to use a reflection in a consteval context even though it itself is not a constant expression.
For me, at least, I found the distinction between constant expressions and consteval to be one of the more difficult topics when first learning reflection.
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@RyanJK5 If you have suggested wording, that would be awesome. I think there are still some gaps in my understanding around this.
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