mtcore::Optional< T * > Struct Template Reference

Represents a pointer that may or may not be null. More...

#include <optional.hpp>

Inheritance diagram for mtcore::Optional< T * >:

Collaboration diagram for mtcore::Optional< T * >:

Public Member Functions
	Optional ()
	Creates an empty Optional.
	Optional (T *value)
	Creates an Optional from a value.
bool	operator== (const Optional &other) const noexcept
	Checks if value is equal to another Optional.
bool	has_value () const noexcept
T	value_or (const T &def) const noexcept
	Returns the value in the optional, or a default value if the optional is empty.
T &	value () noexcept
const T &	value () const noexcept
bool	copy_if_present (T *&out) const noexcept
	Copies a value to a reference output destination if a value is present Designed to be used by simple iterators as part of a while loop on a next() method Example:
bool	copy_if_present (std::remove_const_t< T > &out) const noexcept
	Copies a value to a reference output destination if a value is present Designed to be used by simple iterators as part of a while loop on a next() method Example:
bool	move_if_present (std::remove_const_t< T > *&out) noexcept
	Moves a value to a reference output destination if a value is present.
bool	move_if_present (std::remove_const_t< T > &out) noexcept
	Moves a value to a reference output destination if a value is present.
const T &	operator* () const
	Dereferences the internal value.
const T *	operator-> () const
	Dereferences the internal value.
T &	operator* ()
	Dereferences the internal value.
T *	operator-> ()
	Dereferences the internal value.
	Optional ()
	Creates an empty Optional.
	Optional (const T &value)
	Creates an Optional from a value.
	Optional (T &&value)
	Creates an Optional from a value.
bool	operator== (const Optional &other) const noexcept
	Checks if value is equal to another Optional.
bool	operator== (const T &other) const noexcept
	Checks if value is equal to a non-Optional value.
T	value_or (const T &def) const noexcept
	Returns the value in the optional, or a default value if the optional is empty.
bool	has_value () const noexcept
bool	empty () const noexcept
T &	value () noexcept
const T &	value () const noexcept
bool	copy_if_present (std::remove_const_t< T > &out) const noexcept
	Copies a value to a reference output destination if a value is present Designed to be used by simple iterators as part of a while loop on a next() method Example:
bool	move_if_present (T &out) noexcept
	Moves a value to a reference output destination if a value is present.
const T &	operator* () const
	Dereferences the internal value.
T &	operator* ()
	Dereferences the internal value.
const T *	operator-> () const
	Dereferences the internal value.
T *	operator-> ()
	Dereferences the internal value.

Detailed Description

template<typename T>
struct mtcore::Optional< T * >

Represents a pointer that may or may not be null.

Allows pulling out the underlying value pointed to as well as the pointer itself

Definition at line 48 of file optional.hpp.

Constructor & Destructor Documentation

Optional() [1/5]

template<typename T>

mtcore::Optional< T * >::Optional ( )

inline

Creates an empty Optional.

Definition at line 56 of file optional.hpp.

: v(nullptr) {}

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Optional() [2/5]

template<typename T>

mtcore::Optional< T * >::Optional ( T * value )

inline

Creates an Optional from a value.

Definition at line 61 of file optional.hpp.

: v(value) {}

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Optional() [3/5]

mtcore::Optional< T >::Optional ( )

inline

Creates an empty Optional.

Definition at line 243 of file optional.hpp.

: v(std::monostate{}) { ensure(!has_value()); }

Optional() [4/5]

mtcore::Optional< T >::Optional ( const T & value )

inline

Creates an Optional from a value.

Definition at line 248 of file optional.hpp.

: v(value) {}

Optional() [5/5]

mtcore::Optional< T >::Optional ( T && value )

inline

Creates an Optional from a value.

Definition at line 253 of file optional.hpp.

: v(std::forward<T>(value)) {}

Member Function Documentation

copy_if_present() [1/3]

template<typename T>

bool mtcore::Optional< T * >::copy_if_present ( std::remove_const_t< T > & out ) const

inlinenodiscardnoexcept

Copies a value to a reference output destination if a value is present Designed to be used by simple iterators as part of a while loop on a next() method Example:

auto iter = myCollection.iter();
T myVal;
while (iter.next().copy_if_present(myVal)) {
   // loop contents
}

Parameters

out	Where to put the destination

Returns

true if a value was copied, false otherwise

Definition at line 143 of file optional.hpp.

                                                                                 {
      if (has_value()) {
        out = *v;
      }
      return has_value();
    }

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copy_if_present() [2/3]

bool mtcore::Optional< T >::copy_if_present ( std::remove_const_t< T > & out ) const

inlinenodiscardnoexcept

Copies a value to a reference output destination if a value is present Designed to be used by simple iterators as part of a while loop on a next() method Example:

auto iter = myCollection.iter();
T myVal;
while (iter.next().copy_if_present(myVal)) {
   // loop contents
}

Parameters

out	Where to put the destination

Returns

true if a value was copied, false otherwise

Definition at line 327 of file optional.hpp.

                                                                                 {
      if (has_value()) {
        out = std::get<T>(v);
        return true;
      }
      return false;
    }

copy_if_present() [3/3]

template<typename T>

bool mtcore::Optional< T * >::copy_if_present ( T *& out ) const

inlinenodiscardnoexcept

Copies a value to a reference output destination if a value is present Designed to be used by simple iterators as part of a while loop on a next() method Example:

auto iter = myCollection.iter();
T* myVal;
while (iter.next().copy_if_present(myVal)) {
   // loop contents
}

Parameters

out	Where to put the destination

Returns

true if a value was copied, false otherwise

Definition at line 120 of file optional.hpp.

                                                               {
      if (has_value()) {
        out = v;
      }
      return has_value();
    }

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empty()

bool mtcore::Optional< T >::empty ( ) const

inlinenodiscardnoexcept

Returns

if is empty

Definition at line 299 of file optional.hpp.

{ return std::holds_alternative<std::monostate>(v); }

has_value() [1/2]

template<typename T>

bool mtcore::Optional< T * >::has_value ( ) const

inlinenodiscardnoexcept

Returns

if has a value

Definition at line 81 of file optional.hpp.

{ return v != nullptr; }

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has_value() [2/2]

bool mtcore::Optional< T >::has_value ( ) const

inlinenodiscardnoexcept

Returns

if has a value

Definition at line 294 of file optional.hpp.

{ return std::holds_alternative<T>(v); }

move_if_present() [1/3]

template<typename T>

bool mtcore::Optional< T * >::move_if_present ( std::remove_const_t< T > & out )

inlinenodiscardnoexcept

Moves a value to a reference output destination if a value is present.

Will mark the Optional as empty Designed to be used by simple iterators as part of a while loop on a next() method Example:

auto iter = myCollection.iter();
T myVal;
while (iter.next().move_if_present(myVal)) {
   // loop contents
}

Parameters

out	Where to put the destination

Returns

true if a value was copied, false otherwise

Definition at line 193 of file optional.hpp.

                                                                           {
      if (has_value()) {
        out = std::move(*v);
      }
      mtdefer { v = nullptr; };
      return has_value();
    }

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move_if_present() [2/3]

template<typename T>

bool mtcore::Optional< T * >::move_if_present ( std::remove_const_t< T > *& out )

inlinenodiscardnoexcept

Moves a value to a reference output destination if a value is present.

Will mark the Optional as empty Designed to be used by simple iterators as part of a while loop on a next() method Example:

auto iter = myCollection.iter();
T* myVal;
while (iter.next().move_if_present(myVal)) {
   // loop contents
}

Parameters

out	Where to put the destination

Returns

true if a value was copied, false otherwise

Definition at line 167 of file optional.hpp.

                                                                            {
      mtdefer { v = nullptr; };
      if (has_value()) {
        out = std::move(v);
        return true;
      }
      return false;
    }

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move_if_present() [3/3]

bool mtcore::Optional< T >::move_if_present ( T & out )

inlinenodiscardnoexcept

Moves a value to a reference output destination if a value is present.

Will mark the Optional as empty Designed to be used by simple iterators as part of a while loop on a next() method Example:

auto iter = myCollection.iter();
T myVal;
while (iter.next().move_if_present(myVal)) {
   // loop contents
}

Parameters

out	Where to put the destination

Returns

true if a value was copied, false otherwise

Definition at line 352 of file optional.hpp.

                                                        {
      if (has_value()) {
        out = std::move(std::get<T>(v));
        v   = std::monostate{};
        return true;
      }
      return false;
    }

operator*() [1/4]

template<typename T>

T & mtcore::Optional< T * >::operator* ( )

inline

Dereferences the internal value.

Definition at line 220 of file optional.hpp.

                   {
      ensure(has_value(), "CANNNOT DERERFERENCE NULL OPTIONAL");
      return *v;
    }

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operator*() [2/4]

T & mtcore::Optional< T >::operator* ( )

inline

Dereferences the internal value.

Definition at line 380 of file optional.hpp.

                   {
      ensure(has_value(), "CANNNOT DERERFERENCE NULL OPTIONAL");
      return std::get<T>(v);
    }

operator*() [3/4]

template<typename T>

const T & mtcore::Optional< T * >::operator* ( ) const

inline

Dereferences the internal value.

Definition at line 204 of file optional.hpp.

                               {
      ensure(has_value(), "CANNNOT DERERFERENCE NULL OPTIONAL");
      return *v;
    }

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operator*() [4/4]

const T & mtcore::Optional< T >::operator* ( ) const

inline

Dereferences the internal value.

Definition at line 364 of file optional.hpp.

                               {
      ensure(has_value(), "CANNNOT DERERFERENCE NULL OPTIONAL");
      return std::get<T>(v);
    }

operator->() [1/4]

template<typename T>

T * mtcore::Optional< T * >::operator-> ( )

inline

Dereferences the internal value.

Definition at line 228 of file optional.hpp.

                    {
      ensure(has_value(), "CANNNOT DERERFERENCE NULL OPTIONAL");
      return v;
    }

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operator->() [2/4]

T * mtcore::Optional< T >::operator-> ( )

inline

Dereferences the internal value.

Definition at line 388 of file optional.hpp.

                    {
      ensure(has_value(), "CANNNOT DERERFERENCE NULL OPTIONAL");
      return &std::get<T>(v);
    }

operator->() [3/4]

template<typename T>

const T * mtcore::Optional< T * >::operator-> ( ) const

inline

Dereferences the internal value.

Definition at line 212 of file optional.hpp.

                                {
      ensure(has_value(), "CANNNOT DERERFERENCE NULL OPTIONAL");
      return v;
    }

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operator->() [4/4]

const T * mtcore::Optional< T >::operator-> ( ) const

inline

Dereferences the internal value.

Definition at line 372 of file optional.hpp.

                                {
      ensure(has_value(), "CANNNOT DERERFERENCE NULL OPTIONAL");
      return &std::get<T>(v);
    }

operator==() [1/3]

template<typename T>

bool mtcore::Optional< T * >::operator== ( const Optional< T * > & other ) const

inlinenoexcept

Checks if value is equal to another Optional.

Definition at line 66 of file optional.hpp.

                                                          {
      if (v == nullptr) {
        return other.v == nullptr;
      }
      if (other.v == nullptr) {
        return false;
      }
 
      ensure(v && other.v, "EXISTS CHECK FAILED");
      return v == other.v;
    }

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operator==() [2/3]

bool mtcore::Optional< T >::operator== ( const Optional< T * > & other ) const

inlinenoexcept

Checks if value is equal to another Optional.

Definition at line 258 of file optional.hpp.

                                                          {
      if (has_value() != other.has_value()) {
        return false;
      }
      if (!has_value()) {
        return true;
      }
 
      ensure(has_value() && other.has_value(), "EXISTS CHECK FAILED");
      return std::get<T>(v) == std::get<T>(other.v);
    }

operator==() [3/3]

bool mtcore::Optional< T >::operator== ( const T & other ) const

inlinenoexcept

Checks if value is equal to a non-Optional value.

Definition at line 273 of file optional.hpp.

                                                   {
      if (!has_value()) {
        return false;
      }
      return std::get<T>(v) == other;
    }

value() [1/4]

template<typename T>

const T & mtcore::Optional< T * >::value ( ) const

inlinenodiscardnoexcept

Definition at line 99 of file optional.hpp.

                                                  {
      ensure(has_value(), "CANNOT GET VALUE WHEN OPTIONAL IS EMPTY");
      return *v;
    }

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value() [2/4]

const T & mtcore::Optional< T >::value ( ) const

inlinenodiscardnoexcept

Definition at line 306 of file optional.hpp.

                                                  {
      ensure(has_value(), "CANNOT GET VALUE WHEN OPTIONAL IS EMPTY");
      return std::get<T>(v);
    }

value() [3/4]

template<typename T>

T & mtcore::Optional< T * >::value ( )

inlinenodiscardnoexcept

Definition at line 94 of file optional.hpp.

                                      {
      ensure(has_value(), "CANNOT GET VALUE WHEN OPTIONAL IS EMPTY");
      return *v;
    }

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value() [4/4]

T & mtcore::Optional< T >::value ( )

inlinenodiscardnoexcept

Definition at line 301 of file optional.hpp.

                                      {
      ensure(has_value(), "CANNOT GET VALUE WHEN OPTIONAL IS EMPTY");
      return std::get<T>(v);
    }

value_or() [1/2]

template<typename T>

T mtcore::Optional< T * >::value_or ( const T & def ) const

inlinenodiscardnoexcept

Returns the value in the optional, or a default value if the optional is empty.

Parameters

def	Default value

Definition at line 87 of file optional.hpp.

                                                          {
      if (has_value()) {
        return value();
      }
      return def;
    }

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value_or() [2/2]

T mtcore::Optional< T >::value_or ( const T & def ) const

inlinenodiscardnoexcept

Returns the value in the optional, or a default value if the optional is empty.

Parameters

def	Default value

Definition at line 284 of file optional.hpp.

                                                          {
      if (has_value()) {
        return value();
      }
      return def;
    }

---

The documentation for this struct was generated from the following file:

• optional.hpp