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"Open questions" moved to GitHub issues

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Mateusz Pusz
2019-11-12 22:17:06 +01:00
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@@ -842,44 +842,3 @@ In order to extend the library with custom dimensions the user has to:
constexpr auto operator""_B(long double l) { return units::quantity<byte, long double>(l); } constexpr auto operator""_B(long double l) { return units::quantity<byte, long double>(l); }
} }
``` ```
## Open questions
1. Should we ensure that dimension is always a result of `derived_dimension` and unit is a result
of `derived_unit`? How to do it?
2. What to do with `std::chrono::duration`?
3. Should we provide `seconds<int>` or stay with `quantity<second, int>`?
4. What is the best way to add support for temperatures?
Temperature absolute values not only require `std::ratio` but also should be adjusted/shifted
by some constant values (i.e. [°C] = [K] − 273.15). Relative temperatures does need an offset.
Users will most probably have problems with differentiating those two. Maybe the best solution
is to provide only `K` support in quantity and provide non-member helper conversion functions
with verbose names to convert to `°C` and `°C`?
5. Do we need a non-linear scale?
6. Should we provide integral UDLs or just leave floating point ones?
7. Should we provide support for dimensionless quantities?
Because dimensionless quantities have no associated units, they behave as normal scalars,
and allow implicit conversion to and from the underlying value type or types that are
convertible to/from that value type.
8. Should we standardize accompany tools (downcasting facility, `type_list` operations, `common_ratio`, etc)?
9. `k`, `K`, `W`, `F` UDLs conflict with gcc GNU extensions (<https://gcc.gnu.org/onlinedocs/gcc-4.3.0/gcc/Fixed_002dPoint.html>)
for floating point types.
10. `J` UDL conflicts with imaginary constants GCC extension
11. `erg` (CGS energy) UDL conflicts with engineering syntax
12. Do we need custom/multiple systems?
13. How "moment of force" is different from "energy"?