bool operator==(const_reference lhs, const_reference rhs) noexcept; template<typename ScalarType> bool operator==(const_reference lhs, const ScalarType rhs) noexcept; template<typename ScalarType> bool operator==(ScalarType lhs, const const_reference rhs) noexcept;
Compares two JSON values for equality according to the following rules:
operator==
.ScalarType
: a scalar type according to std::is_scalar<ScalarType>::value
lhs
(in) : first value to consider
rhs
(in) : second value to consider
whether the values lhs
and rhs
are equal
No-throw guarantee: this function never throws exceptions.
Linear.
!!! 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 { return std::abs(a - b) <= epsilon; } ``` Or you can self-defined operator equal function like this: ```cpp bool my_equal(const_reference lhs, const_reference rhs) { const auto lhs_type lhs.type(); const auto rhs_type rhs.type(); if (lhs_type == rhs_type) { switch(lhs_type) // self_defined case case value_t::number_float: return std::abs(lhs - rhs) <= std::numeric_limits<float>::epsilon(); // other cases remain the same with the original ... } ... } ```
??? example
The example demonstrates comparing several JSON types. ```cpp --8<-- "examples/operator__equal.cpp" ``` Output: ```json --8<-- "examples/operator__equal.output" ```