variant objects can represent values of different types. More...

#include <TSAVariant.h>

Inheritance diagram for tsa::variant:

Public Member Functions
void	clear (void)
	Returns self to an 'undefined' state where defined() returns 'false'. 'undefined' essentially means 'no data available' / 'N/A' or 'null' as used by some database systems. Note that an 'undefined' variant can still have a type.

bool	defined (void) const
	Returns true if a value has been assigned and the object is in a 'defined' date. In other words it is 'not-null'. More...

std::string &	get_string_ref (void) const

bool	is_equal (const variant &other) const
	Returns true if self is identical to other. More...

bool	is_numeric (void) const
	Returns true if value type is numeric. Numeric types are: More...

bool	is_owner (void) const
	Returns true if the object is the owner of the pointer value. More...

std::string &	str (void) const

template<typename T >
T	to (void) const
	Gets to. More...

bool	to_bool (void) const
	Returns this object's data as a bool, converting the data if required. Throws an exception if conversion fails. More...

date	to_date (void) const
	Returns this object's data as a date, converting the data if required. Throws an exception if conversion fails. More...

date_time	to_datetime (void) const
	Returns this object's data as a date_time, converting the data if required. Throws an exception if conversion fails. More...

double	to_double (void) const
	Returns this object's data as a double, converting the data if required. Throws an exception if conversion fails. More...

float	to_float (void) const
	Returns this object's data as a float, converting the data if required. Throws an exception if conversion fails. More...

int	to_int (void) const
	Returns this object's data as an int, converting the data if required. Throws an exception if conversion fails. More...

int64_t	to_int64 (void) const
	Returns this object's data as a int64_t, converting the data if required. Throws an exception if conversion fails. More...

std::string	to_string (void) const
	Returns this object's data as a std::string, converting the data if required. More...

unsigned	to_uint (void) const
	Returns this object's data as an unsigned it, converting the data if required. Throws an exception if conversion fails. More...

void *	to_void_ptr (void) const
	Returns this object's data as a void_ptr. Throws an exception if type is not type_t::void_ptr. More...

type_t	type (void) const
	Returns the type.

Related Functions
(Note that these are not member functions.)
std::ostream &	operator<< (std::ostream &stream, const variant &var)
	Writes var to stream as text. More...

Constructors / Destructor
	variant (void)
	Constructor. Object state is 'undefined'. defined() returns false.

	variant (type_t type)
	Constructor. Self is initialized to given type. The object remains 'undefined' until a value is assigned. The defined() member returns false. More...

	variant (const variant &other)
	Copy constructor.

	variant (const date_time &val)
	Constructor. Type member is initialized to type_t::datetime and value to val.

	variant (const date &val)
	Constructor. Type member is initialized to type_t::date and value to val.

	variant (double val)
	Constructor. Type member is initialized to type_t::float64 and value to val.

	variant (int val)
	Constructor. Type member is initialized to type_t::int32 and value to val.

	variant (int64_t val)
	Constructor. Type member is initialized to type_t::int64 and value to val.

	variant (uint64_t val)
	Constructor. Type member is initialized to type_t::int64 and value to val. (value will be signed)

	variant (bool val)
	Constructor. Type member is initialized to type_t::boolean and value to val.

	variant (unsigned val)
	Constructor. Type member is initialized to type_t::uint32 and value to val.

	variant (float val)
	Constructor. Type member is initialized to type_t::float32 and value to val.

	variant (const tsa::string &val)
	Constructor. Type member is initialized to string and value to val.

	variant (const std::string &val)
	Constructor. Type member is initialized to type_t::string and value to val.

	variant (const char *val)
	Constructor. Type member is initialized to type_t::string and value to val.

	variant (char val)
	Constructor. Type member is initialized to type_t::string and value to val.

	variant (const object *val)

	variant (const void *val)
	Constructor. Type member is initialized to type_t::void_ptr and data member to val. Does NOT assume ownership of the pointer.

	~variant (void)
	Destructor.

Assignment
const variant &	operator= (const variant &other)
	Assignment operator. Self will be identical to other.

const variant &	operator= (unsigned val)
	Assignment operator. Type is set to type_t::uint32.

const variant &	operator= (const date_time &val)
	Assignment operator. Type is set to type_t::datetime.

const variant &	operator= (const date &val)
	Assignment operator. Type is set to type_t::date.

const variant &	operator= (int val)
	Assignment operator. Type is set to type_t::int32.

const variant &	operator= (int64_t val)
	Assignment operator. Type is set to type_t::int64.

const variant &	operator= (uint64_t val)
	Assignment operator. Type is set to type_t::int64.

const variant &	operator= (bool val)
	Assignment operator. Type is set to boolean.

const variant &	operator= (float val)
	Assignment operator. Type is set to type_t::float32.

const variant &	operator= (double val)
	Assignment operator. Type is set to type_t::float64.

const variant &	operator= (void *val)
	Assignment operator. Type is set to type_t::void_ptr.

const variant &	operator= (const char *val)
	Assignment operator. Type is set to type_t::string.

const variant &	operator= (const tsa::string &val)

const variant &	operator= (const std::string &val)
	Assignment operator. Type is set to type_t::string.

void	assign__no_type_chg (object *val)

void	assign__no_type_chg (float value)
	Assigns value. Type stays unchanged.

void	assign__no_type_chg (double value)
	Assigns value. Type stays unchanged.

void	assign__no_type_chg (unsigned value)
	Assigns value. Type stays unchanged.

void	assign__no_type_chg (int value)
	Assigns value. Type stays unchanged.

void	assign__no_type_chg (int64_t value)
	Assigns value. Type stays unchanged.

void	assign__no_type_chg (unsigned long int value)
	Assigns value. Type stays unchanged.

void	assign__no_type_chg (bool value)
	Assigns value. Type stays unchanged.

void	assign__no_type_chg (const variant &other)
	Assigns other to self while retaining self's type and attempting to convert other's data. If other is 'undefined', self will also be set to 'undefined'. More...

void	assign__no_type_chg (void *value)
	Assigns value. Type stays unchanged.

void	assign__no_type_chg (const tsa::string &val)
	Assigns value. Type stays unchanged.

void	assign__no_type_chg (const std::string &val)
	Assigns value. Type stays unchanged.

void	assign__no_type_chg (const char *val)
	Assigns value. Type stays unchanged.

void	assign__no_type_chg (const date_time &val)
	Assigns value. Type stays unchanged.

void	assign__no_type_chg (const date &val)
	Assigns value. Type stays unchanged.

Casting Operators
template<typename T >
T	get (void) const
	Returns the objects data. The object's type must match the template typename. If not, an exception is thrown. More...

	operator float (void) const
	Identical to to_float().

	operator unsigned (void) const
	Identical to to_float().

	operator double (void) const
	Identical to to_float().

	operator int (void) const
	Identical to to_float().

	operator int64_t (void) const
	Identical to to_float().

	operator uint64_t (void) const

	operator bool (void) const
	Identical to to_bool().

	operator void * (void) const
	Identical to to_void_ptr().

Detailed Description

variant objects can represent values of different types.

Data types are enumerated by tsa::type_t:

type_t::float32 - 32 bit floating point
type_t::uint32 - 32 bit unsigned integer
type_t::int32 - 32 bit integer
type_t::int64 - 64 bit integer
type_t::float64 - 64 bit floating point
type_t::boolean - boolean true or false
type_t::datetime - DateTime
type_t::date - Date
type_t::string - string / std::string
type_t::void_ptr - generic pointer

The default constructor leaves the object in an 'undefined' state. In this case, the defined() member returns false. Constructors that declare a value parameter will take on the type of the given argument. For example

variant v(3.3);

assert(v.type() == type_t::float64);

To put a variant object back into an 'undefined' state, call the clear() member.

Value Access:

Use the get<T>() template function to access the variant value such as:

variant phi = 1.618;

double d = phi.get<double>();

If the variant does not already have the requested type, then get() will throw an exception.

Value Conversion

In order to convert access a value as a specific type that may not match the variant type, use members such as:

such as:

variant phi = "1.618";

double d = phi.as_double();

Note that class variant will do its best to convert values between types, even if a loss of precision is possible. It will however throw and exception if the conversion is not possible.

Cast Operators

It is also possible to cast a variant instance using 'explicit' cast operators:

variant phi = "1.618";

double d = (double)phi;

Type Conversion during Assignment

Normally a variant will take on the type of object that is assigned to it. It is also possible to force the variant to retain its type during assigment using the assign__no_type_chg() members.

variant phi = "";
assert(phi.type() == type_t::string;
phi.assign__no_type_chg(1.618);        //assign a double
assert(phi.type() == type_t::string);  //instance still has type type_t::string.

.

Conversion Rules for Boolean Conversion

All values are considered 'true' unless in the following list:

0
0.0
"0"
"false" or "FALSE" (case insensitive)
"f" or "F" (case insensitive)
nullptr.

Constructor & Destructor Documentation

tsa::variant::variant ( type_t type )

explicit

Constructor. Self is initialized to given type. The object remains 'undefined' until a value is assigned. The defined() member returns false.

Parameters

type The type.

Member Function Documentation

void tsa::variant::assign__no_type_chg ( const variant & other )

Assigns other to self while retaining self's type and attempting to convert other's data. If other is 'undefined', self will also be set to 'undefined'.

Parameters

other The other variant.

bool tsa::variant::defined ( void ) const

Returns true if a value has been assigned and the object is in a 'defined' date. In other words it is 'not-null'.

Returns: true if defined, else false.

template<typename T >

T tsa::variant::get ( void ) const

Returns the objects data. The object's type must match the template typename. If not, an exception is thrown.

Template Parameters

T

type parameter. Must be one of the following:

type_t::float32 - 32 bit floating point
type_t::uint32 - 32 bit unsigned integer
type_t::int32 - 32 bit integer
type_t::int64 - 64 bit integer
type_t::float64 - 64 bit floating point
type_t::boolean - boolean true or false
type_t::datetime - DateTime
type_t::date - Date
type_t::string - string / std::string
type_t::void_ptr - generic pointer.

Returns: The object value.

bool tsa::variant::is_equal ( const variant & other ) const

Returns true if self is identical to other.

Parameters

other The other.

Returns: true if equal, false if not.

bool tsa::variant::is_numeric ( void ) const

Returns true if value type is numeric. Numeric types are:

type_t::float64
type_t::int64
type_t::float32
type_t::int32
type_t::uint32.
Returns
true if numeric, false if not.

bool tsa::variant::is_owner ( void ) const

Returns true if the object is the owner of the pointer value.

This is only relevant in case self is of pointer type (e.g. type_t::string, type_t::void_ptr). If If self is the owner, then self's destructor will delete the data pointed to by the pointer.

Returns: true if owner, false if not.

template<typename T >

T tsa::variant::to ( void ) const

Gets to.

Template Parameters

T	Generic type parameter.

Returns: A T.

bool tsa::variant::to_bool ( void ) const

Returns this object's data as a bool, converting the data if required. Throws an exception if conversion fails.

Conversion Rules

All values are considered 'true' unless in the following list:

0
0.0
"0"
"false" or "FALSE" (case insensitive)
"f" or "F" (case insensitive)
nullptr.
Returns
This object as a bool.

date tsa::variant::to_date ( void ) const

Returns this object's data as a date, converting the data if required. Throws an exception if conversion fails.

Returns: date.

date_time tsa::variant::to_datetime ( void ) const

Returns this object's data as a date_time, converting the data if required. Throws an exception if conversion fails.

Returns: date_time.

double tsa::variant::to_double ( void ) const

Returns this object's data as a double, converting the data if required. Throws an exception if conversion fails.

Returns: double.

float tsa::variant::to_float ( void ) const

Returns this object's data as a float, converting the data if required. Throws an exception if conversion fails.

Returns: float.

int tsa::variant::to_int ( void ) const

Returns this object's data as an int, converting the data if required. Throws an exception if conversion fails.

Returns: int.

int64_t tsa::variant::to_int64 ( void ) const

Returns this object's data as a int64_t, converting the data if required. Throws an exception if conversion fails.

Returns: int64_t.

std::string tsa::variant::to_string ( void ) const

Returns this object's data as a std::string, converting the data if required.

Returns: This object as a std::string.

unsigned tsa::variant::to_uint ( void ) const

Returns this object's data as an unsigned it, converting the data if required. Throws an exception if conversion fails.

Returns: unsigned int.

void * tsa::variant::to_void_ptr ( void ) const

Returns this object's data as a void_ptr. Throws an exception if type is not type_t::void_ptr.

Returns: This object as a void*.

Public Member Functions

Related Functions

Constructors / Destructor

Assignment

Casting Operators

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation