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276 lines
6.1 KiB
Markdown
276 lines
6.1 KiB
Markdown
---
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title: "cyclic_value"
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---
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{{< callout type="info">}}
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Header: `cyclic_value.h`
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Since: `TBC`
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{{< /callout >}}
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Provides a value that cycles between two limits.
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Supports increments, decrements and arbitrary advance.
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Supports compile time and runtime variants.
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```cpp
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template <typename T, const T First = 0, const T Last = 0>
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class cyclic_value
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```
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Static asserts if `Last` < `First`.
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**Example**
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```cpp
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etl::cyclic_value<int, 2, 7> value_ct; // Compile time. Fixed range of 2 to 7 inclusive.
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etl::cyclic_value<int> value_rt(2, 7); // Run time. Modifiable range.
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value_rt.set(3, 8);
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```
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## Constructor
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### Run time limits
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```cpp
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cyclic_value<T>() noexcept;
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```
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Constructs a cyclic value of type `T` with an initial value of `first`.
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`constexpr` from C++11.
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---
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```cpp
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cyclic_value<T>(T first, T last);
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```
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Constructs a *run time* cyclic value of type `T` with limits of `first` and `last` and an initial value of `first`.
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Asserts an `etl::cyclic_value_reversed_limits` if `last` < `first`.
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`constexpr` from C++11.
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---
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```cpp
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cyclic_value<T>(T first, T last, T initial);
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```
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Constructs a cyclic value of type `T` with limits of `first` and `last` and an initial value of `initial`.
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`initial` will be clamped to be in the range `(first, last)`.
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Asserts an `etl::cyclic_value_reversed_limits` if `last` < `first`.
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`constexpr` from C++11.
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### Compile time limits
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```cpp
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cyclic_value<T, First, Last>() noexcept;
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```
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Constructs a cyclic value of type `T` default constructed with an initial value of `First`.
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`constexpr` from C++11.
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---
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```cpp
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cyclic_value<T, First, Last>(T initial) noexcept;
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```
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Constructs a cyclic value of type `T` constructed with an `initial`.
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`initial` will be clamped to be in the range `(First, Last)`.
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`constexpr` from C++11.
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## Modifiers
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```cpp
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cyclic_value& operator ++() noexcept;
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cyclic_value& operator ++(int) noexcept;
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```
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Increments the value. If the value is at the last value then is set to the first.
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`constexpr` from C++14.
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---
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```cpp
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cyclic_value& operator --() noexcept;
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cyclic_value& operator --(int) noexcept;
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```
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Decrements the value. If the value is at the first value then is set to the last.
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`constexpr` from C++14.
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---
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```cpp
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template <typename TStep>
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void advance(TStep n) noexcept;
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```
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Advances the value by the specified amount, wrapping if necessary.
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`constexpr` from C++14.
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---
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```cpp
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template <typename TStep>
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cyclic_value& operator +=(TStep n) noexcept;
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```
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Advances the value by the specified amount, wrapping if necessary.
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`constexpr` from C++14.
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---
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```cpp
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template <typename TStep>
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cyclic_value& operator -=(TStep n) noexcept;
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```
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Decrements the value by the specified amount, wrapping if necessary.
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`constexpr` from C++14.
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## Access
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```cpp
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T get() const;
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```
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Gets the current value.
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`constexpr` from C++11.
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---
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```cpp
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T first() const noexcept;
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```
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Gets the first value.
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`constexpr` from C++11.
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---
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```cpp
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T last() const noexcept;
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```
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Gets the last value.
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`constexpr` from C++11.
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---
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```cpp
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void set(T first, T last) noexcept;
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```
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Sets the new *run time* `first` and `last` values. Sets the current value to `first`.
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Asserts an `etl::cyclic_value_reversed_limits` if `last` < `first`.
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`constexpr` from C++14.
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---
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```cpp
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void set(T value) noexcept;
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```
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Sets the current value.
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`constexpr` from C++14.
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---
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```cpp
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void to_first() noexcept;
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```
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Sets the current value to the first value.
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`constexpr` from C++14.
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---
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```cpp
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void to_last() noexcept;
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```
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Sets the current value to the last value.
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`constexpr` from C++14.
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## Operations
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```cpp
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void swap(cyclic_value<T, FIRST, LAST>& other) noexcept;
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```
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Swaps with another cyclic value.
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`constexpr` from C++14.
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## Operators
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```cpp
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operator T() noexcept;
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operator const T() const noexcept;
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```
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Conversion operators to `T`.
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`constexpr` from C++11.
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---
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```cpp
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cyclic_value& operator =(T t) noexcept;
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```
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Sets the current value to `t`.
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`constexpr` from C++14.
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## Non-member functions
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```cpp
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template <typename T, const T FIRST, const T LAST>
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void swap(cyclic_value<T, FIRST, LAST>& lhs, cyclic_value<T, FIRST, LAST>& rhs) noexcept
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```
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Swaps two cyclic values.
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---
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```cpp
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template <typename T, const T FIRST, const T LAST>
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bool operator == (cyclic_value<T, FIRST, LAST>& lhs, cyclic_value<T, FIRST, LAST>& rhs) noexcept
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```
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Checks equality of two cyclic values.
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`constexpr` from C++11.
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{{< callout type="warning">}}
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After version `20.49.0` equality is judged only by the current value.
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Previously the first and last limits were also considered.
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<= 20.49.0
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`etl::cyclic_value<int, 2, 7>(3) != etl::cyclic_value<int, 2, 6>(3)`
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`etl::cyclic_value<int>(2, 7, 3) != etl::cyclic_value<int>(2, 6, 3)`
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> 20.49.0
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`etl::cyclic_value<int, 2, 7>(3) == etl::cyclic_value<int, 2, 6>(3)`
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`etl::cyclic_value<int>(2, 7, 3) == etl::cyclic_value<int>(2, 6, 3)`
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{{< /callout >}}
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---
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```cpp
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template <typename T, const T FIRST, const T LAST>
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bool operator != (cyclic_value<T, FIRST, LAST>& lhs, cyclic_value<T, FIRST, LAST>& rhs) noexcept
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```
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Checks inequality of two cyclic values.
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`constexpr` from C++11.
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---
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```cpp
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template <typename T, const T FIRST, const T LAST>
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bool operator < (cyclic_value<T, FIRST, LAST>& lhs, cyclic_value<T, FIRST, LAST>& rhs) noexcept
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```
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Checks if the current value of `lhs` is less than the current value of `rhs`.
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`constexpr` from C++11.
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---
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```cpp
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template <typename T, const T FIRST, const T LAST>
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bool operator <= (cyclic_value<T, FIRST, LAST>& lhs, cyclic_value<T, FIRST, LAST>& rhs) noexcept
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```
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Checks if the current value of `lhs` is less than or equal the current value of `rhs`.
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`constexpr` from C++11.
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---
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```cpp
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template <typename T, const T FIRST, const T LAST>
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bool operator > (cyclic_value<T, FIRST, LAST>& lhs, cyclic_value<T, FIRST, LAST>& rhs) noexcept
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```
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Checks if the current value of `lhs` is greater than the current value of `rhs`.
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`constexpr` from C++11.
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---
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```cpp
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template <typename T, const T FIRST, const T LAST>
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bool operator >= (cyclic_value<T, FIRST, LAST>& lhs, cyclic_value<T, FIRST, LAST>& rhs) noexcept
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```
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Checks if the current value of `lhs` is greater than or equal the current value of `rhs`.
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`constexpr` from C++11.
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