Maybe< T > Class Template Reference

#include <v8-maybe.h>

Public Member Functions
V8_INLINE bool	IsNothing () const
V8_INLINE bool	IsJust () const
V8_INLINE T	ToChecked () const
V8_INLINE void	Check () const
V8_WARN_UNUSED_RESULT V8_INLINE bool	To (T *out) const
V8_INLINE T	FromJust () const
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

Friends
template<class U >
Maybe< U >	Nothing ()
template<class U >
Maybe< U >	Just (const 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 29 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 43 of file v8-maybe.h.

References v8::api_internal::FromJustIsNothing(), Maybe< T >::IsJust(), and V8_UNLIKELY.

FromJust()

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 60 of file v8-maybe.h.

References v8::api_internal::FromJustIsNothing(), Maybe< T >::IsJust(), and V8_UNLIKELY.

Referenced by Maybe< T >::operator==(), and Maybe< T >::ToChecked().

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 69 of file v8-maybe.h.

IsJust()

template<class T >

V8_INLINE bool IsJust ( ) const

inline

Definition at line 32 of file v8-maybe.h.

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

IsNothing()

template<class T >

V8_INLINE bool IsNothing ( ) const

inline

Definition at line 31 of file v8-maybe.h.

operator!=()

template<class T >

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

inline

Definition at line 78 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 73 of file v8-maybe.h.

References Maybe< T >::FromJust(), and Maybe< T >::IsJust().

Referenced by Maybe< T >::operator!=(), and Maybe< void >::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 51 of file v8-maybe.h.

References Maybe< T >::IsJust(), and V8_LIKELY.

ToChecked()

template<class T >

V8_INLINE T ToChecked ( ) const

inline

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

Definition at line 37 of file v8-maybe.h.

References Maybe< T >::FromJust().

Friends And Related Symbol Documentation

Just

template<class T >

template<class U >

Maybe< U > Just ( const U &  u )

friend

Nothing

template<class T >

template<class U >

Maybe< U > Nothing ( )

friend

Definition at line 96 of file v8-maybe.h.

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

• include/v8-maybe.h