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📝 fix and extend documentation of discarded values

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Niels Lohmann
2020-08-19 20:26:06 +02:00
parent 3be6ee3525
commit b386f4de0b
14 changed files with 109 additions and 27 deletions
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23
doc/mkdocs/docs/api/basic_json/operator_eq.md
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@ -12,11 +12,10 @@ bool operator==(ScalarType lhs, const const_reference rhs) noexcept;
Compares two JSON values for equality according to the following rules:
- Two JSON values are equal if (1) they are from the same type and (2) their stored values are the same according to
their respective `operator==`.
- Two JSON values are equal if (1) they are not discarded, (2) they are from the same type, and (3) their stored values
are the same according to their respective `operator==`.
- Integer and floating-point numbers are automatically converted before comparison. Note that two NaN values are always
treated as unequal.
- Two JSON null values are equal.
## Template parameters
@ -45,11 +44,19 @@ Linear.
## Notes
- Floating-point inside JSON values numbers are compared with `json::number_float_t::operator==` which is
`double::operator==` by default. To compare floating-point while respecting an epsilon, an alternative
[comparison function](https://github.com/mariokonrad/marnav/blob/master/include/marnav/math/floatingpoint.hpp#L34-#L39)
could be used, for instance
!!! note
- NaN values never compare equal to themselves or to other NaN values.
- JSON `#!cpp null` values are all equal.
- Discarded values never compare equal to themselves.
!!! note
Floating-point numbers inside JSON values numbers are compared with `json::number_float_t::operator==` which is
`double::operator==` by default. To compare floating-point while respecting an epsilon, an alternative
[comparison function](https://github.com/mariokonrad/marnav/blob/master/include/marnav/math/floatingpoint.hpp#L34-#L39)
could be used, for instance
```cpp
template<typename T, typename = typename std::enable_if<std::is_floating_point<T>::value, T>::type>
inline bool is_same(T a, T b, T epsilon = std::numeric_limits<T>::epsilon()) noexcept
@ -78,8 +85,6 @@ Linear.
}
```
- NaN values never compare equal to themselves or to other NaN values.
## Example
??? example