Maybe< T > Class Template Reference

#include <v8-maybe.h>

Inheritance diagram for Maybe< T >:

Collaboration diagram for Maybe< T >:

Public Member Functions
constexpr	Maybe ()=default
V8_INLINE	Maybe (internal::NullMaybeType)
V8_INLINE bool	IsNothing () const
V8_INLINE bool	IsJust () const
V8_INLINE bool	IsEmpty () const
V8_INLINE T	ToChecked () const
V8_INLINE void	Check () const
V8_WARN_UNUSED_RESULT V8_INLINE bool	To (T *out) const
V8_WARN_UNUSED_RESULT V8_INLINE bool	MoveTo (T *out) &&
V8_INLINE T	FromJust () const &
V8_INLINE T	FromJust () &&
V8_INLINE T	FromMaybe (const T &default_value) const
V8_INLINE bool	operator== (const Maybe &other) const
V8_INLINE bool	operator!= (const Maybe &other) const
Public Member Functions inherited from ConditionalStackAllocatedBase< T >
	CPPGC_STACK_ALLOCATED ()

Friends
template<class U >
Maybe< U >	Just (const U &u)
template<class U , std::enable_if_t<!std::is_lvalue_reference_v< U > > * >
Maybe< U >	Just (U &&u)

Detailed Description

template<class T>
class v8::Maybe< T >

A simple Maybe type, representing an object which may or may not have a value, see https://hackage.haskell.org/package/base/docs/Data-Maybe.html.

If an API method returns a Maybe<>, the API method can potentially fail either because an exception is thrown, or because an exception is pending, e.g. because a previous API call threw an exception that hasn't been caught yet, or because a TerminateExecution exception was thrown. In that case, a "Nothing" value is returned.

Definition at line 39 of file v8-maybe.h.

Constructor & Destructor Documentation

Maybe() [1/2]

template<class T >

constexpr Maybe ( )

constexprdefault

Maybe() [2/2]

template<class T >

V8_INLINE Maybe ( internal::NullMaybeType  )

inline

Definition at line 43 of file v8-maybe.h.

Member Function Documentation

Check()

template<class T >

V8_INLINE void Check ( ) const

inline

Short-hand for ToChecked(), which doesn't return a value. To be used, where the actual value of the Maybe is not needed like Object::Set.

Definition at line 63 of file v8-maybe.h.

References v8::api_internal::FromJustIsNothing(), and Maybe< T >::IsJust().

FromJust() [1/2]

template<class T >

V8_INLINE T FromJust ( ) &&

inline

Converts this Maybe<> to a value of type T. If this Maybe<> is nothing (empty), V8 will crash the process.

Definition at line 99 of file v8-maybe.h.

References v8::api_internal::FromJustIsNothing(), and Maybe< T >::IsJust().

FromJust() [2/2]

template<class T >

V8_INLINE T FromJust ( ) const &

inline

Converts this Maybe<> to a value of type T. If this Maybe<> is nothing (empty), V8 will crash the process.

Definition at line 90 of file v8-maybe.h.

References v8::api_internal::FromJustIsNothing(), and Maybe< T >::IsJust().

FromMaybe()

template<class T >

V8_INLINE T FromMaybe ( const T &  default_value ) const

inline

Converts this Maybe<> to a value of type T, using a default value if this Maybe<> is nothing (empty).

Definition at line 108 of file v8-maybe.h.

IsEmpty()

template<class T >

V8_INLINE bool IsEmpty ( ) const

inline

Same as IsNothing(). It's useful for unified handling of empty states with v8::MaybeLocal<T>.

Definition at line 52 of file v8-maybe.h.

References Maybe< T >::IsNothing().

IsJust()

template<class T >

V8_INLINE bool IsJust ( ) const

inline

Definition at line 46 of file v8-maybe.h.

Referenced by Maybe< T >::Check(), Maybe< T >::FromJust(), Maybe< T >::FromJust(), Maybe< T >::MoveTo(), Maybe< T >::operator==(), and Maybe< T >::To().

IsNothing()

template<class T >

V8_INLINE bool IsNothing ( ) const

inline

Definition at line 45 of file v8-maybe.h.

Referenced by Maybe< T >::IsEmpty().

MoveTo()

template<class T >

V8_WARN_UNUSED_RESULT V8_INLINE bool MoveTo ( T *  out ) &&

inline

Converts this Maybe<> to a value of type T, moving out of it. If this Maybe<> is nothing (empty), |false| is returned and |out| is left untouched.

Definition at line 81 of file v8-maybe.h.

References Maybe< T >::IsJust().

operator!=()

template<class T >

V8_INLINE bool operator!= ( const Maybe< T > &  other ) const

inline

Definition at line 117 of file v8-maybe.h.

References Maybe< T >::operator==().

operator==()

template<class T >

V8_INLINE bool operator== ( const Maybe< T > &  other ) const

inline

Definition at line 112 of file v8-maybe.h.

References Maybe< T >::IsJust().

Referenced by Maybe< T >::operator!=().

To()

template<class T >

V8_WARN_UNUSED_RESULT V8_INLINE bool To ( T *  out ) const

inline

Converts this Maybe<> to a value of type T. If this Maybe<> is nothing (empty), |false| is returned and |out| is left untouched.

Definition at line 71 of file v8-maybe.h.

References Maybe< T >::IsJust().

ToChecked()

template<class T >

V8_INLINE T ToChecked ( ) const

inline

An alias for |FromJust|. Will crash if the Maybe<> is nothing.

Definition at line 57 of file v8-maybe.h.

Friends And Related Symbol Documentation

Just [1/2]

template<class T >

template<class U >

Maybe< U > Just ( const U &  u )

friend

Just [2/2]

template<class T >

template<class U , std::enable_if_t<!std::is_lvalue_reference_v< U > > * >

Maybe< U > Just ( U &&  u )

friend

---

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

• include/v8-maybe.h