Detailed Description

template<class HashFn, class Compare>
class te::AnyValue< HashFn, Compare >

A std::any -like type that serves as the value_type for AnySet instances.

AnyValue instances are always dynamically-allocated and are typically owned by an AnySet instance. AnyValue has no user-visible constructors and is neither copy nor move-assignable.

AnyValue instances can be spliced into and extracted from AnySet instances whose HashFn and KeyEqual types are the same as HashFn and Compare respectively.

Following the conventions of std::any, the value contained in a particular AnyValue instance can be obtained using special 'cast' functions. The cast functions provided for AnyValue are exact_cast(), polymorphic_cast(), and unsafe_cast(). Additionally, non-cast-style accessor and query functions is(), as(), get(), get_default_ref(), get_default_val(), and try_as() are provided as well.

Template Parameters

HashFn	- The type of the hash function object used in the corresponding `AnySet<HashFn,` `Compare>` instances.
Compare	- The type of the equality function object (`KeyEqual`) used in the corresponding `AnySet<HashFn,` `Compare>` instances.

See also: AnySet; AnyHash

#include <AnyNode.h>

Public Types
using	self_type = AnyValue< HashFn, Compare >

using	hasher = HashFn

using	key_equal = Compare

Public Member Functions
	AnyValue (const AnyValue &)=delete

	AnyValue (AnyValue &&)=delete

virtual const std::type_info &	typeinfo () const =0
	Get a reference to a std::type_info object that indicates the type of the contained object. More...

Public Attributes
const std::size_t	hash
	The hash code obtained by invoking an instance of `HashFn` on the contained object. More...

Protected Member Functions
	AnyValue (std::size_t hash_v)

virtual bool	compare_to (const AnyValue &other, Compare comp) const =0

virtual bool	equals (const AnyValue &other) const =0

virtual bool	not_equals (const AnyValue &other) const =0

virtual void	write (std::ostream &os) const =0

virtual std::unique_ptr< self_type >	clone () const =0

Friends
template<class , class , class >
struct	AnySet

struct	detail::AnyList< HashFn, Compare >

std::ostream &	operator<< (std::ostream &os, const AnyValue &any_v)
	Write the contained object to the given `std::ostream` using the stream insertion << operator. More...

Comparison Operations
template<class T >
bool	operator== (const AnyValue &left, const T &right)
	Query whether the contained object in `left` is of type `T` and equal to `right`.

template<class T >
bool	operator== (const T &left, const AnyValue &right)
	Query whether the contained object in `right` is of type `T` and equal to `left`.

template<class T >
bool	operator!= (const T &left, const AnyValue &right)
	Query whether the contained object in `right` is not of type `T` or not equal to `left`.

template<class T >
bool	operator!= (const AnyValue &left, const T &right)
	Query whether the contained object in `left` is not of type `T` or not equal to `right`.

bool	operator== (const AnyValue &left, const AnyValue &right)
	Query whether the contained objects in `left` and `right` are of the same equality-comparable type, and subsequently whether the contained, same-type objects compare equal using operator==. More...

bool	operator!= (const AnyValue &left, const AnyValue &right)
	Query whether the contained objects in `left` and `right` are of different types, or whether the contained same-type objects compare not-equal using operator!=. More...

bool	compare (const AnyValue &left, const AnyValue &right, Compare comp)
	Query whether the contained objects in `left` and `right` are of the same type, and subsequently whether the contained same-type objects compare equal using the provided instance of the `Compare` comparison function object. More...

template<class T , class Comp = Compare, class = std::enable_if_t<not std::is_same_v<T, self_type>>>
bool	compare (const T &left, const AnyValue &right, Comp comp)
	Query whether the contained object in `right` is of type `T` and subsequently whether the contained object compares equal to `left` using the provided instance of the `Comp` comparison function object. More...

template<class T , class Comp = Compare, class = std::enable_if_t<not std::is_same_v<T, self_type>>>
bool	compare (const AnyValue &left, const T &right, Comp comp)
	Query whether the contained object in `left` is of type `T` and subsequently whether the contained object compares equal to `right` using the provided instance of the `Comp` comparison function object. More...

Related Functions
(Note that these are not member functions.)
Queries
template<class T , class H , class C >
bool	is (const AnyValue< H, C > &any_v)
	Check if `any_v` contains an object of type T. More...

Maker/Factory Functions
Note that these functions are intended primarilly for internal use.
template<class T , class H , class C , class ... Args>
std::unique_ptr< AnyValue< H, C > >	make_any_value (std::size_t hash_value, Args &&... args)
	Constructs a std::unique_ptr<AnyValue<H, C>> suitable for splicing into an AnySet instance. More...

template<class T , class H , class C , class ... Args>
std::unique_ptr< AnyValue< H, C > >	make_any_value (H hasher, Args &&... args)
	Constructs a std::unique_ptr<AnyValue<H, C>> suitable for splicing into an `AnySet<H,` `C>` instance. More...

Casts
template<class To , class H , class C >
To	polymorphic_cast (const AnyValue< H, C > &any_v)
	Access the contained object through a reference to dynamic type `To`. More...

template<class To , class H , class C >
To	polymorphic_cast (const AnyValue< H, C > *any_v)
	Access the contained object through a pointer to dynamic type `To`. More...

template<class To , class H , class C >
To	exact_cast (const AnyValue< H, C > &any_v)
	Access the contained object. More...

template<class To , class H , class C >
To	exact_cast (const AnyValue< H, C > *any_v)
	Access the contained object. More...

template<class To , class H , class C >
To	unsafe_cast (const AnyValue< H, C > &any_v)
	Access the contained object without dynamic type checking. More...

Higher-Level Accessors
template<class T , class H , class C >
const T *	try_as (const AnyValue< H, C > &any_v)
	Get a pointer to the contained object of type T. If the contained object is not an instance of type T, returns nullptr. More...

template<class T , class H , class C >
const T &	as (const AnyValue< H, C > &self)
	Get a reference to the contained object of type T. If the contained object is not an instance of type T, throws a std::bad_cast. More...

template<class T , class H , class C >
const T &	get (const AnyValue< H, C > &any_v)

template<class T , class H , class C , class DefaultRef >
const std::decay_t< T > &	get_default_ref (const AnyValue< H, C > &any_v, DefaultRef &&default_ref)
	Get the contained value in `any_v` through a reference to const `T`. More...

template<class T , class H , class C , class DefaultVal >
T	get_default_val (const AnyValue< H, C > &any_v, DefaultVal &&default_val)
	Get a copy of the contained value in `any_v` of type `T`. More...

Member Function Documentation

◆ typeinfo()

template<class HashFn, class Compare>

virtual const std::type_info& te::AnyValue< HashFn, Compare >::typeinfo ( ) const

pure virtual

Get a reference to a std::type_info object that indicates the type of the contained object.

Returns: A std::type_info object that indicates the type of the contained object.

Implemented in te::detail::TypedValue< Value, HashFn, Compare >.

Friends And Related Function Documentation

◆ as()

template<class T , class H , class C >

const T & as ( const AnyValue< H, C > & self )

This function works by attempting an exact_cast() followed by, if the exact_cast() failed, a polymorphic_cast(). The polymorphic_cast() is only attempted if T is a non-final class type.

Template Parameters

T	- The type of the contained value, absent of reference (&) or const/volatile qualifiers.

Parameters

any_v - The AnyValue instance whose contained object is to be accessed.

Returns: A reference of type const T& to the contained object.

Exceptions

std::bad_cast

See also: get(); try_as(); get_default_ref(); get_default_val(); AnyValue

◆ compare [1/3]

template<class HashFn, class Compare>

bool compare	(	const AnyValue< HashFn, Compare > &	left,
		const AnyValue< HashFn, Compare > &	right,
		Compare	comp
	)

friend

Query whether the contained objects in left and right are of the same type, and subsequently whether the contained same-type objects compare equal using the provided instance of the Compare comparison function object.

Parameters

left	- An instance of `te::AnyValue<HashFn,` `Compare>`.
right	- An instance of `te::AnyValue<HashFn,` `Compare>`.
comp	- The instance of `Compare` to use for comparing the contained objects.

Returns: true if the contained types are identical and compare equal when comp is invoked with the contained objects.

◆ compare [2/3]

template<class HashFn, class Compare>

template<class T , class Comp = Compare, class = std::enable_if_t<not std::is_same_v<T, self_type>>>

bool compare	(	const T &	left,
		const AnyValue< HashFn, Compare > &	right,
		Comp	comp
	)

friend

Query whether the contained object in right is of type T and subsequently whether the contained object compares equal to left using the provided instance of the Comp comparison function object.

Parameters

left	- An instance of type `T`.
right	- An instance of `te::AnyValue<HashFn,` `Compare>`.
comp	- An instance of an arbitrary comparison function type `Comp` to use for comparing the contained objects.

Returns: true if the contained types are identical and compare equal when comp is invoked with the contained objects.

◆ compare [3/3]

template<class HashFn, class Compare>

template<class T , class Comp = Compare, class = std::enable_if_t<not std::is_same_v<T, self_type>>>

bool compare	(	const AnyValue< HashFn, Compare > &	left,
		const T &	right,
		Comp	comp
	)

friend

Query whether the contained object in left is of type T and subsequently whether the contained object compares equal to right using the provided instance of the Comp comparison function object.

Parameters

left	- An instance of `te::AnyValue<HashFn,` `Compare>`.
right	- An instance of type `T`.
comp	- An instance of an arbitrary comparison function type `Comp` to use for comparing the contained objects.

Returns: true if the contained types are identical and compare equal when comp is invoked with the contained objects.

◆ exact_cast() [1/2]

template<class To , class H , class C >

To exact_cast ( const AnyValue< H, C > & any_v )

If the type of contained object is not the same as the requested type (after stripping off references and cv qualifiers, i.e. std::decay), throws a std::bad_cast.

Template Parameters

To	- The type to access the contained object as. May be a reference or value type.

Parameters

any_v - The AnyValue instance whose contained object is to be accessed.

Returns: A reference to (or copy of, if To is a non-reference type) the contained object.

Exceptions

std::bad_cast

See also: polymorphic_cast(); unsafe_cast(); AnyValue

◆ exact_cast() [2/2]

template<class To , class H , class C >

To exact_cast ( const AnyValue< H, C > * any_v )

If the type of contained object is not the same as the requested type (after stripping off top-level pointer and then cv qualifiers), returns null.

Template Parameters

To	- The type to access the contained object as. Must be a pointer to the expected type of the contained object.

Parameters

any_v - The AnyValue instance whose contained object is to be accessed.

Returns: A pointer to the contained object of type T.

See also: polymorphic_cast(); unsafe_cast(); AnyValue

◆ get()

template<class T , class H , class C >

const T & get ( const AnyValue< H, C > & any_v )

See also: as(); try_as(); get_default_ref(); get_default_val(); AnyValue

◆ get_default_ref()

template<class T , class H , class C , class DefaultRef >

const std::decay_t< T > & get_default_ref	(	const AnyValue< H, C > &	any_v,
		DefaultRef &&	default_ref
	)

If the value contained in any_v is of type T, as determined by calling try_as() (try_as<T>(any_v)), returns the contained value by 'reference to const T, otherwise the provided "default" reference default_ref is returned.

Note: If default_ref is not an lvalue reference to T, the call fails to compile (via static_assert). This is to prevent silently returning a dangling reference to T. See this talk for further details and justification.

Template Parameters

T	- The type of the contained value, absent of reference (&) or const/volatile qualifiers.

Parameters

any_v	- The AnyValue instance whose contained object is being accessed.
default_ref	- An lvalue reference to an object of type `T` which will be returned if `any_v` does not contain an object of type `T`.

Returns: A const reference to the object of type T contained in any_v, or default_ref if any_v does not contain an object of type T.

See also: as(); get(); try_as(); get_default_val(); AnyValue

◆ get_default_val()

template<class T , class H , class C , class DefaultVal >

T get_default_val	(	const AnyValue< H, C > &	any_v,
		DefaultVal &&	default_val
	)

If the value contained in any_v is of type T, as determined by calling try_as() (try_as<T>(any_v)), returns a copy of the contained value, otherwise an object of type T is constructed from the provided "default" value, default_val, and returned.

Note: Unlike get_default_ref(), the given "default" value, default_val, may be a rvalue or an instance of a type other than T, so long as an object of type T can be constructed from the provided value.

Template Parameters

T	- The type to access, absent of reference (&) or const/volatile qualifiers.

Parameters

any_v	- The AnyValue instance whose contained object is being accessed.
default_ref	- The default value to constuct an instance of `T` from in the case that `any_v` does not contain an object of type `T`.

Returns: If any_v contains an object of type T, returns a copy of the constained object, otherwise, returns an instance of type T constructed from default_val.

See also: as(); get(); try_as(); get_default_ref(); AnyValue

◆ is()

template<class T , class H , class C >

bool is ( const AnyValue< H, C > & any_v )

T must match the contained type exactly; is() returns false, even if T is an accessible base of the type of the contained object.

Template Parameters

T	- The type of the contained value, absent of reference (&) or const/volatile qualifiers.

Parameters

any_v - The AnyValue instance whose contained type is to be queried.

Returns: true if the AnyValue instance contains an object of type T, false otherwise.

See also: AnyValue

◆ make_any_value() [1/2]

template<class T , class H , class C , class ... Args>

std::unique_ptr< AnyValue< H, C > > make_any_value	(	std::size_t	hash_value,
		Args &&...	args
	)

Template Parameters

T	- The type of the contained value.
H	- The type of the hash function object used by AnySet instances that the returned AnyValue instance can be spliced into.
H	- The type of the comparison (KeyEqual) function object used by AnySet instances that the returned AnyValue instance can be spliced into.

Parameters

hash_value	- The resultant hash code obtained from hashing the to-be-constructed `T` instance.
args	- arguments to forward to `T's` constructor.

Note: hash_value is a "trust me" argument. Only call this overload if you are absolutely sure of what the hash code of the constructed object will be. Use of this overload is appropriate, for example, when move-constructing a long std::string whose hash has already been computed.

Remarks: Throws any exceptions thrown by T's constructor, by calling hasher with the constructed value of T, or by std::make_unique();

◆ make_any_value() [2/2]

template<class T , class H , class C , class ... Args>

std::unique_ptr< AnyValue< H, C > > make_any_value	(	H	hasher,
		Args &&...	args
	)

Template Parameters

T	- The type of the contained value.
H	- The type of the hash function object used by AnySet instances that the returned AnyValue instance can be spliced into.
H	- The type of the comparison (KeyEqual) function object used by AnySet instances that the returned AnyValue instance can be spliced into.

Parameters

hasher	- The instance of `H` to use to compute the hash of contained `T` object after it is constructed in the AnyValue.
args	- Arguments to forward to `T's` constructor.

Remarks: Throws any exceptions thrown by T's constructor, by calling hasher with the constructed value of T, or by std::make_unique();

◆ operator!=

template<class HashFn, class Compare>

bool operator!=	(	const AnyValue< HashFn, Compare > &	left,
		const AnyValue< HashFn, Compare > &	right
	)

friend

Query whether the contained objects in left and right are of different types, or whether the contained same-type objects compare not-equal using operator!=.

Note: If either of the contained objects are of non-inequality-comparable types, this function returns true. This is the case even if the contained objects are of the same, empty type.

Returns: true if the contained types are not identical, if the contained types are not inequality-comparable, or if the contained same-type objects compare not-equal via operator!=.

◆ operator<<

template<class HashFn, class Compare>

std::ostream& operator<<	(	std::ostream &	os,
		const AnyValue< HashFn, Compare > &	any_v
	)

friend

Write the contained object to the given std::ostream using the stream insertion << operator.

Note: If the contained object is of a type that is not streamable (has no operator<<(std::ostream, const T&) overload), writes a string of the form "AnyValue(typeid.name='<typeid(T).name()>', hash=<hash code>)".

◆ operator==

template<class HashFn, class Compare>

bool operator==	(	const AnyValue< HashFn, Compare > &	left,
		const AnyValue< HashFn, Compare > &	right
	)

friend

Query whether the contained objects in left and right are of the same equality-comparable type, and subsequently whether the contained, same-type objects compare equal using operator==.

Note: If either of the contained objects are of non-equality-comparable types, this function returns false. This is the case even if the contained objects are of the same, empty type.

Returns: true if the contained types are identical, the contained type is equality-comparable, and if the contained same-type objects compare equal via operator==.

◆ polymorphic_cast() [1/2]

template<class To , class H , class C >

To polymorphic_cast ( const AnyValue< H, C > & any_v )

Unlike exact_cast() or unsafe_cast(), polymorphic_cast() can access the AnyValue instance's contained object through a reference to a base type of the contained object. For example, an AnyValue instance which contains an object of type std::runtime_error could be polymorphic_cast()'d to const std::exception&.

Note: Neither the type of the contained object nor target type of the cast need be of polymorphic type for this cast to work. polymorphic_cast() can cast through non-polymorphic inheritence heirarchies.

If the contained object is of non-class type, throws a std::bad_cast.

If the contained object is an instance of a final class type, throws a std::bad_cast, even if the contained object is an instance of To.

If To is a reference to non-class or final class type, the cast fails to compile.

Template Parameters

To	- The type to cast to. Should take the form `const T&`.

Parameters

any_v - The AnyValue instance whose contained object is being accessed.

Returns: A reference to the contained object of the requested type.

Exceptions

std::bad_cast

See also: exact_cast(); unsafe_cast(); AnyValue

◆ polymorphic_cast() [2/2]

template<class To , class H , class C >

To polymorphic_cast ( const AnyValue< H, C > * any_v )

Unlike exact_cast() or unsafe_cast(), polymorphic_cast() can access the AnyValue instance's contained object through a (possibly polymorphic) pointer to a base type of the contained object. For example, an AnyValue instance which contains an object of type std::runtime_error could be polymorphic_cast()'d to const std::exception*.

Note: Neither the type of the contained object nor target type of the cast need be of polymorphic type for this cast to work. polymorphic_cast() can cast through non-polymorphic inheritence heirarchies.

If the contained object is of non-class type, returns nullptr.

If the contained object is an instance of a final class type, returns nullptr, even if the contained object is an instance of To.

If To is a pointer to non-class or final class type, the cast fails to compile.

Template Parameters

To	- The type to cast to. Should take the form `const T*`.

Parameters

any_v - The AnyValue instance whose contained object is being accessed.

Returns: A pointer to the contained object of the requested type.

See also: exact_cast(); unsafe_cast(); AnyValue

◆ try_as()

template<class T , class H , class C >

const T * try_as ( const AnyValue< H, C > & any_v )

This function works by attempting to return te::exact_cast<const T*>(&self) followed by a te::polymorphic_cast<const T*>(&self) if the exact_cast() failed. The polymorphic_cast() is only attempted if T is a non-final class type.

Template Parameters

T	- The type of the contained value, absent of reference (&) or const/volatile qualifiers.

Parameters

any_v - The AnyValue instance whose contained object is to be accessed.

Returns: A pointer of type const T* to the contained object if the contained object has type T, otherwise null.

See also: as(); get(); get_default_ref(); get_default_val(); AnyValue

◆ unsafe_cast()

template<class To , class H , class C >

To unsafe_cast ( const AnyValue< H, C > & any_v )

If the type of contained object is not the same as the requested type (after stripping off top-level reference and then cv qualifiers, i.e. std::decay), then the behavior is undefined.

Template Parameters

To	- The type to access the contained object as. Must be the type of the contained object or const reference thereto.

Parameters

any_v - The AnyValue instance whose contained object is to be accessed.

Returns: A reference to the contained object if To is a reference type, or a copy if To is a non-reference type

See also: exact_cast(); polymorphic_cast(); AnyValue

Member Data Documentation

◆ hash

template<class HashFn, class Compare>

const std::size_t te::AnyValue< HashFn, Compare >::hash

The hash code obtained by invoking an instance of HashFn on the contained object.

This member data member is provided primarilly so that lookup in an AnySet instance can "fail fast". Mismatched hash values can indicate object inequality and elide the need to access the contained object, which requires virtual dispatch.

Inheritance diagram for te::AnyValue< HashFn, Compare >:

[legend]

Collaboration diagram for te::AnyValue< HashFn, Compare >:

[legend]

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

/home/tim/Projects/AnySet/include/anyset/AnyNode.h

Detailed Description

template<class HashFn, class Compare> class te::AnyValue< HashFn, Compare >

Public Types

Public Member Functions

Public Attributes

Protected Member Functions

Friends

Related Functions

Member Function Documentation

◆ typeinfo()

Friends And Related Function Documentation

◆ as()

◆ compare [1/3]

◆ compare [2/3]

◆ compare [3/3]

◆ exact_cast() [1/2]

◆ exact_cast() [2/2]

◆ get()

◆ get_default_ref()

◆ get_default_val()

◆ is()

◆ make_any_value() [1/2]

◆ make_any_value() [2/2]

◆ operator!=

◆ operator<<

◆ operator==

◆ polymorphic_cast() [1/2]

◆ polymorphic_cast() [2/2]

◆ try_as()

◆ unsafe_cast()

Member Data Documentation

◆ hash

template<class HashFn, class Compare>
class te::AnyValue< HashFn, Compare >