Non-owning reference to Lua value. More...

Inheritance diagram for Valref:

Public Member Functions
Life cycle
	Valref (const Valref &) noexcept=default
	Copy constructor. More...

template<typename ValueType >
Valref &	operator= (ValueType &&val)
	Assignment. More...

Type info and conversion
template<typename T >
T	cast () const
	Explicit checked conversion to supported types. More...

template<typename T >
T	optcast (const T &backupValue=T()) const noexcept
	Safe conversion to supported types [Lua 5.2- only]. More...

template<typename T >
T	to () const noexcept
	Unchecked conversion to supported types. More...

template<typename T >
T	to (const T &backupValue) const noexcept
	Safe conversion to supported types. More...

	operator bool () const

	operator int () const

	operator unsigned int () const

	operator long long () const

	operator unsigned long long () const

	operator float () const

	operator double () const

	operator CFunction () const

	operator LightUserData () const

	operator const char * () const

	operator std::string () const

template<typename T >
bool	is () const noexcept
	Check if the value convertible to given type. More...

bool	isInteger () const noexcept
	Check if the value is an integer number [Lua 5.3+ only] More...

ValueType	type () const noexcept
	Actual type of referenced value.

Comparisons (made through Lua)
bool	operator== (Valobj &&rhs) const

bool	operator!= (Valobj &&rhs) const

bool	operator< (Valobj &&rhs) const

bool	operator> (Valobj &&rhs) const

bool	operator<= (Valobj &&rhs) const

bool	operator>= (Valobj &&rhs) const

Indexation
Temporary	operator[] (Valobj &&index_) const noexcept
	Indexation.

Function calls
template<typename... Args>
Temporary	operator() (Args &&...args) const noexcept
	Natural call form. More...

template<typename... Args>
Temporary	call (Args &&...args) const noexcept
	Call method. More...

template<typename... Args>
Temporary	pcall (Args &&...args) const noexcept
	Protected call method. More...

Closure handling
Temporary	upvalue (size_t index) const noexcept
	Upvalue access inside closures. More...

Valset	getUpvalues () const noexcept
	Retrieve upvalues and their names. More...

ClosureInfo	getClosureInfo () const noexcept
	Retrieve information about closure [Lua 5.2+ only]. More...

size_t	getClosureInfo () const noexcept
	Retrieve information about closure [Lua 5.1 only]. More...

Miscellaneous operations
Temporary	len () const noexcept
	Length [Lua 5.2+ only].

size_t	rawlen () const noexcept
	Raw length (no metamethods) [Lua 5.2+ only].

size_t	len () const noexcept
	Length [Lua 5.1 only].

Temporary	mt () const noexcept
	Metatable. More...

Temporary	linked () const noexcept
	Linked value [Lua 5.3+ only]. More...

Related Functions
(Note that these are not member functions.)
Comparisons (made through Lua)
bool	operator== (Valobj &&lhs, const Valref &rhs)

bool	operator!= (Valobj &&lhs, const Valref &rhs)

bool	operator< (Valobj &&lhs, const Valref &rhs)

bool	operator> (Valobj &&lhs, const Valref &rhs)

bool	operator<= (Valobj &&lhs, const Valref &rhs)

bool	operator>= (Valobj &&lhs, const Valref &rhs)

Concatenation
Temporary	operator& (Valobj &&lhs, Valobj &&rhs) const noexcept
	Concatenation. More...

Arithmetics (Lua 5.2+ only).
Temporary	operator- (Valobj &&lhs)
	[Lua 5.2+ only] More...

Temporary	operator+ (Valobj &&lhs, const Valobj &rhs) noexcept
	[Lua 5.2+ only] More...

Temporary	operator- (Valobj &&lhs, const Valobj &rhs) noexcept
	[Lua 5.2+ only] More...

Temporary	operator* (Valobj &&lhs, const Valobj &rhs) noexcept
	[Lua 5.2+ only] More...

Temporary	operator/ (Valobj &&lhs, const Valobj &rhs) noexcept
	[Lua 5.2+ only] More...

Temporary	operator% (Valobj &&lhs, const Valobj &rhs) noexcept
	[Lua 5.2+ only] More...

Temporary	operator^ (Valobj &&lhs, const Valobj &rhs) noexcept
	Power [Lua 5.2+ only]. More...

Temporary	idiv (Valobj &&lhs, Valobj &&rhs)
	Integer division [Lua 5.3+ only]. More...

Binary operations (Lua 5.3+ only)
Temporary	band (Valobj &&lhs, Valobj &&rhs)
	Bitwise AND [Lua 5.3+ only]. More...

Temporary	bor (Valobj &&lhs, Valobj &&rhs)
	Bitwise OR [Lua 5.3+ only]. More...

Temporary	bxor (Valobj &&lhs, Valobj &&rhs)
	Bitwise XOR [Lua 5.3+ only]. More...

Temporary	bneg (Valobj &&lhs)
	Bitwise NOT [Lua 5.3+ only]. More...

Temporary	shl (Valobj &&lhs, Valobj &&rhs)
	Bit shift left [Lua 5.3+ only]. More...

Temporary	shr (Valobj &&lhs, Valobj &&rhs)
	Bit shift right [Lua 5.3+ only]. More...

Detailed Description

Non-owning reference to Lua value.

This is a reference to a specific slot on Lua stack. The operations with Lua value inside that slot are performed through this object.

Note: This class also covers values that are not actually on the stack but are addressed with pseudo-indices.

Constructor & Destructor Documentation

Valref ( const Valref & )

defaultnoexcept

Copy constructor.

Copies of Valref point to the same stack slot. Be careful with copying Valref objects just as you would be with normal references. This copy constructor is enabled so it is possible to pass references as function arguments.

Note: Obviously, this operation is not matched in Temporary interface.

Member Function Documentation

Valref& operator= ( ValueType && val )

Assignment.

Lua values, supported native types or registered userdata can be assigned to a referenced stack slot.

Note: Some types of Temporary objects may be assigned to (indexers, metatables and so on). Assignment to other kinds (like arithmetic results or length query) has no sense and thus cannot be done.

T cast ( ) const

Explicit checked conversion to supported types.

Call this function with type to be converted to.

Exceptions

std::runtime_error if the value type is incompatible.

Template Parameters

T	the type to cast to, one of those: bool (NB: ANY value can be converted to boolean) int unsigned int float double const char* CFunction LightUserData any user data type (see this section), returned by reference

T optcast ( const T & backupValue = T() ) const

noexcept

Safe conversion to supported types [Lua 5.2- only].

Deprecated:

use to function instead.

Returns: Converted value or fallback value if the conversion cannot be made.

Template Parameters

T	the type to cast to. Converts to all types supported by cast except user data.

T to ( ) const

noexcept

Unchecked conversion to supported types.

Returns: Conversion result or unspecified value if the conversion cannot be made. Use when you are sure what the type of value is and don't want additional checks during conversion.

Template Parameters

T	the type to cast to. Converts to all types supported by cast including user data.

Note: For userdata type a reference is returned.

T to ( const T & backupValue ) const

noexcept

Safe conversion to supported types.

Returns: Converted value or fallback value if the conversion cannot be made.

Template Parameters

T	the type to cast to. Converts to all types supported by cast except user data.

operator bool ( ) const

Never fails.

operator int ( ) const

Exceptions

std::runtime_error if the value type is incompatible.

Note: Strings may be converted to numbers.

operator unsigned int ( ) const

Exceptions

std::runtime_error if the value type is incompatible.

Note: Strings may be converted to numbers.

operator long long ( ) const

Exceptions

std::runtime_error if the value type is incompatible.

Note: Strings may be converted to numbers.

operator unsigned long long ( ) const

Exceptions

std::runtime_error if the value type is incompatible.

Note: Strings may be converted to numbers.

operator float ( ) const

Exceptions

std::runtime_error if the value type is incompatible.

Note: Strings may be converted to numbers.

operator double ( ) const

Exceptions

std::runtime_error if the value type is incompatible.

Note: Strings may be converted to numbers.

operator CFunction ( ) const

Exceptions

std::runtime_error if the value type is incompatible.

operator LightUserData ( ) const

Exceptions

std::runtime_error if the value type is incompatible.

operator const char * ( ) const

Exceptions

std::runtime_error if the value type is incompatible.

Note: Numbers are convertible to strings.

operator std::string ( ) const

inline

Exceptions

std::runtime_error if the value type is incompatible.

Note: Numbers are convertible to strings.

bool is ( ) const

noexcept

Check if the value convertible to given type.

Exception: is<bool> checks if value type is actually boolean, because any value can be converted to bool.

Template Parameters

T

the type to check compatibility with, one of those:

Nil
bool
int
unsigned int
float
double
const char*
std::string
CFunction (true if the value is a C function)
LFunction (true if the value is a function, no matter C or Lua bytecode)
LightUserData
Table
any user data type (see this section)

Note: All numeric types are interchangeable for this function and check only for numeric format. Use isInteger to check if the number is actually of integer subtype.

bool isInteger ( ) const

noexcept

Check if the value is an integer number [Lua 5.3+ only]

Returns: true if the value is a number and has integer subtype, false otherwise (i.e. the value is floating-point or not a number at all).

Temporary operator() ( Args &&... args ) const

noexcept

Natural call form.

Any suitable value is accepted as an argument.

See also: basic_state_multiret_call

Temporary call ( Args &&... args ) const

noexcept

Call method.

Any suitable value is accepted as an argument.

See also: basic_state_multiret_call

Temporary pcall ( Args &&... args ) const

noexcept

Protected call method.

Any suitable value is accepted as an argument.

See also: basic_state_multiret_call

Temporary upvalue ( size_t index ) const

noexcept

Upvalue access inside closures.

You can read and write upvalues inside closures with this function.

Parameters

index 1-based index of accessed upvalue.

Precondition: this->is<LFunction>()

Exceptions

std::runtime_error on wrong index.

Valset getUpvalues ( ) const

noexcept

Retrieve upvalues and their names.

This function returns values and names of all closure upvalues. Upvalues are always named "" in C closures. Upvalue ordering in Lua functions is undefined.

Precondition: this->is<LFunction>()

Returns: Value-name pairs for each upvalue.

ClosureInfo getClosureInfo ( ) const

noexcept

Retrieve information about closure [Lua 5.2+ only].

This function is applicable only to closures. It returns number of upvalues, parameters and whether function is variadic (accepts variable number of arguments).

Precondition: this->is<LFunction>()

Note: For closures made from C functions nParameters is always 0 and variadic is always true.

size_t getClosureInfo ( ) const

noexcept

Retrieve information about closure [Lua 5.1 only].

This function is applicable only to closures.

Returns: Number of upvalues.

Precondition: this->is<LFunction>()

Temporary mt ( ) const

noexcept

Metatable.

Returns: value's metatable or nil.

Temporary linked ( ) const

noexcept

Linked value [Lua 5.3+ only].

Returns: value's linked value or nil.

This function allows to get and set associated value for userdata. For other types it will produce nil (also for userdata that doesn't have anything associated with it) on read attempts and silently ignore write attempts.

Friends And Related Function Documentation

bool operator==	(	Valobj &&	lhs,
		const Valref &	rhs
	)

bool operator!=	(	Valobj &&	lhs,
		const Valref &	rhs
	)

bool operator<	(	Valobj &&	lhs,
		const Valref &	rhs
	)

bool operator>	(	Valobj &&	lhs,
		const Valref &	rhs
	)

bool operator<=	(	Valobj &&	lhs,
		const Valref &	rhs
	)

bool operator>=	(	Valobj &&	lhs,
		const Valref &	rhs
	)

Temporary operator&	(	Valobj &&	lhs,
		Valobj &&	rhs
	)		const

Note

Chained concatenations are optimized into a single multi-value concatenation;
multiple return values and Valsets are expanded;
the operation symbol '&' has lower priority than '+' and '-' because in C/C++ it means "bitwise AND", which matches priority of concatenation in Lua.

Temporary operator- ( Valobj && lhs )

Temporary operator+	(	Valobj &&	lhs,
		const Valobj &	rhs
	)

Temporary operator-	(	Valobj &&	lhs,
		const Valobj &	rhs
	)

Temporary operator*	(	Valobj &&	lhs,
		const Valobj &	rhs
	)

Temporary operator/	(	Valobj &&	lhs,
		const Valobj &	rhs
	)

Temporary operator%	(	Valobj &&	lhs,
		const Valobj &	rhs
	)

Temporary operator^	(	Valobj &&	lhs,
		const Valobj &	rhs
	)

Warning: The operation symbol '^' has lower priority than '+' and '-' because in C/C++ it means "bitwise XOR", not "power". Use parentheses to group expressions properly.

Temporary idiv	(	Valobj &&	lhs,
		Valobj &&	rhs
	)

Temporary band	(	Valobj &&	lhs,
		Valobj &&	rhs
	)

Temporary bor	(	Valobj &&	lhs,
		Valobj &&	rhs
	)

Temporary bxor	(	Valobj &&	lhs,
		Valobj &&	rhs
	)

Temporary bneg ( Valobj && lhs )

Temporary shl	(	Valobj &&	lhs,
		Valobj &&	rhs
	)

Temporary shr	(	Valobj &&	lhs,
		Valobj &&	rhs
	)

Public Member Functions

Related Functions

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation

Friends And Related Function Documentation