JKQTPExpected< T, E > Struct Template Reference

an "expected" datatype, which can either represent a function result of type T or an error of type E More...

#include <jkqtpexpected.h>

Public Member Functions
	JKQTPExpected ()=delete
	JKQTPExpected (const JKQTPExpected< T, E > &other)=default
	JKQTPExpected (const T &value_)
	JKQTPExpected (JKQTPExpectedUnexpectedType, const E &error_)
const E &	error () const
bool	has_value () const
	operator bool () const
const T &	value () const

Private Attributes
const E	m_error
const bool	m_hasValue
const T	m_value

Detailed Description

template<class T, class E>
struct JKQTPExpected< T, E >

an "expected" datatype, which can either represent a function result of type T or an error of type E

Usage example:

JKQTPExpected<double,QString> toInt(QString s) {
  bool ok=false;
  int i=s.toInt(&ok);
  if (ok) return {i}
  else return { JKQTPUnexpected, QString("cannot convert to int") };
}
 
auto r=toInt("1.0a");
if (r.hasValue()) qDebug()<<"SUCCESS! i="<<r.value();
else qDebug()<<"FAILURE: "<<r.error();

See also

JKQTPExpectedUnexpectedType, JKQTPUnexpected

Constructor & Destructor Documentation

JKQTPExpected() [1/4]

template<class T , class E >

JKQTPExpected< T, E >::JKQTPExpected ( )

delete

JKQTPExpected() [2/4]

template<class T , class E >

JKQTPExpected< T, E >::JKQTPExpected ( const T &  value_ )

inline

JKQTPExpected() [3/4]

template<class T , class E >

JKQTPExpected< T, E >::JKQTPExpected ( const JKQTPExpected< T, E > &  other )

default

JKQTPExpected() [4/4]

template<class T , class E >

JKQTPExpected< T, E >::JKQTPExpected ( JKQTPExpectedUnexpectedType  , const E &  error_  )

inline

Member Function Documentation

error()

template<class T , class E >

const E & JKQTPExpected< T, E >::error ( ) const

inline

has_value()

template<class T , class E >

bool JKQTPExpected< T, E >::has_value ( ) const

inline

operator bool()

template<class T , class E >

JKQTPExpected< T, E >::operator bool ( ) const

inline

value()

template<class T , class E >

const T & JKQTPExpected< T, E >::value ( ) const

inline

Member Data Documentation

m_error

template<class T , class E >

const E JKQTPExpected< T, E >::m_error

private

m_hasValue

template<class T , class E >

const bool JKQTPExpected< T, E >::m_hasValue

private

m_value

template<class T , class E >

const T JKQTPExpected< T, E >::m_value

private

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

• jkqtpexpected.h