wamp::FromVariantConverter Class Reference

Wrapper around a source Variant, used for conversions. More...

#include <cppwamp/variant.hpp>

Public Types
using	SizeType = size_t
	Integer type used to represent the size of array variants.
using	String = std::string
	String type used to represent an object variant key.

Public Member Functions
	FromVariantConverter (const Variant &var)
	Constructor taking a constant variant reference.
SizeType	size () const
	Obtains the current size of the variant. More...
FromVariantConverter &	size (SizeType &n)
	Obtains the current size of the variant. More...
template<typename T >
FromVariantConverter &	operator() (T &value)
	Retrieves a non-composite value from the variant. More...
template<typename T >
FromVariantConverter &	operator[] (T &value)
	Retrieves the next element from an Array variant. More...
template<typename T >
FromVariantConverter &	operator() (const String &key, T &value)
	Retrieves a member from an Object variant. More...
template<typename T , typename U >
FromVariantConverter &	operator() (const String &key, T &value, U &&fallback)
	Retrieves a member from an Object variant, with a fallback value if the member is not found. More...
const Variant &	variant () const
	Returns a constant reference to the wrapped variant.

Static Public Attributes
static constexpr bool	convertingToVariant = false
	Indicates that this converter is used to convert from a variant.

Detailed Description

Wrapper around a source Variant, used for conversions.

This wrapper provides a convenient, uniform syntax for retrieving values from a source variant.

Member Function Documentation

size() [1/2]

FromVariantConverter::SizeType wamp::FromVariantConverter::size ( ) const

inline

Obtains the current size of the variant.

Returns this->variant()->size().

See also

Variant::size

size() [2/2]

FromVariantConverter & wamp::FromVariantConverter::size ( SizeType &  n )

inline

Obtains the current size of the variant.

Returns this->variant()->size().

See also

Variant::size

operator()() [1/3]

template<typename T >

FromVariantConverter & wamp::FromVariantConverter::operator()

(

T &

value

)

Retrieves a non-composite value from the variant.

The variant's value is converted to the destination type via Variant::to.

Precondition

The variant is convertible to the destination type.

Exceptions

error::Conversion

if the variant is not convertible to the destination type.

operator[]()

template<typename T >

FromVariantConverter & wamp::FromVariantConverter::operator[]

(

T &

value

)

Retrieves the next element from an Array variant.

The element is converted to the destination type via Variant::to.

Precondition

The variant is an array.

There are elements left in the variant array.

The element is convertible to the destination type.

Exceptions

error::Conversion	if the variant is not an array.
error::Conversion	if there are no elements left in the variant array.
error::Conversion	if the element is not convertible to the destination type.

operator()() [2/3]

template<typename T >

FromVariantConverter & wamp::FromVariantConverter::operator()	(	const String &	key,
		T &	value
	)

Retrieves a member from an Object variant.

The member is converted to the destination type via Variant::to.

Precondition

The variant is an object.

There exists a member with the given key.

The member is convertible to the destination type.

Exceptions

error::Conversion	if the variant is not an object.
error::Conversion	if there doesn't exist a member with the given key.
error::Conversion	if the member is not convertible to the destination type.

operator()() [3/3]

template<typename T , typename U >

FromVariantConverter & wamp::FromVariantConverter::operator()	(	const String &	key,
		T &	value,
		U &&	fallback
	)

Retrieves a member from an Object variant, with a fallback value if the member is not found.

The member is converted to the destination type via Variant::to.

Precondition

The variant is an object.

The member, if it exists, is convertible to the destination type.

Exceptions

error::Conversion	if the variant is not an object.
error::Conversion	if the existing member is not convertible to the destination type.

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

• cppwamp/variant.hpp