QPatternist::NoneType Class Reference

Represents the special none type. More...

#include <qnonetype_p.h>

Inheritance diagram for QPatternist::NoneType:

Public Types
typedef QExplicitlySharedDataPointer< NoneType >	Ptr
Public Types inherited from QPatternist::ItemType
enum	Category { NodeNameTest = 1, Other = 2 }
enum	InstanceOf { ClassLocalNameTest, ClassNamespaceNameTest, ClassQNameTest, ClassOther }
typedef QList< ItemType::Ptr >	List
typedef QExplicitlySharedDataPointer< ItemType >	Ptr
Public Types inherited from QPatternist::SequenceType
typedef QList< SequenceType::Ptr >	List
typedef QExplicitlySharedDataPointer< const SequenceType >	Ptr

Public Functions
virtual ItemType::Ptr	atomizedType () const
virtual Cardinality	cardinality () const
virtual QString	displayName (const NamePool::Ptr &np) const
virtual bool	isAtomicType () const
virtual bool	isNodeType () const
virtual bool	itemMatches (const Item &item) const
virtual ItemType::Ptr	itemType () const
virtual const ItemType &	operator| (const ItemType &other) const
virtual ItemType::Ptr	xdtSuperType () const
virtual bool	xdtTypeMatches (const ItemType::Ptr &other) const
	Returns true if other matches this type. That is, if other is equal to this type or a subtype of this type. More...
Public Functions inherited from QPatternist::ItemType
virtual InstanceOf	instanceOf () const
	ItemType ()
virtual Category	itemTypeCategory () const
bool	operator!= (const ItemType &other) const
virtual bool	operator== (const ItemType &other) const
virtual	~ItemType ()
Public Functions inherited from QSharedData
	QSharedData ()
	Constructs a QSharedData object with a reference count of 0. More...
	QSharedData (const QSharedData &)
	Constructs a QSharedData object with reference count 0. More...
Public Functions inherited from QPatternist::SequenceType
bool	is (const SequenceType::Ptr &other) const
bool	matches (const SequenceType::Ptr other) const
	SequenceType ()
virtual	~SequenceType ()

Protected Functions
	NoneType ()

Friends
class	CommonSequenceTypes

Additional Inherited Members
Public Variables inherited from QSharedData
QAtomicInt	ref
Related Functions inherited from QPatternist::ItemType
ItemType::Ptr	operator| (const ItemType::Ptr &op1, const ItemType::Ptr &op2)
void	operator|= (ItemType::Ptr &op1, const ItemType::Ptr &op2)
	Computes the union type of op1 and op2, and assigns it to op1. More...

Detailed Description

Represents the special none type.

See also

XQuery 1.0 and XPath 2.0 Formal Semantics, 2.4.3 Content models

XQuery 1.0 and XPath 2.0 Formal Semantics, 7.2.9 The fn:error function

Author

Frans Englich frans.nosp@m..eng.nosp@m.lich@.nosp@m.noki.nosp@m.a.com

Definition at line 75 of file qnonetype_p.h.

Typedefs

Ptr

typedef QExplicitlySharedDataPointer<NoneType> QPatternist::NoneType::Ptr

Definition at line 79 of file qnonetype_p.h.

Constructors and Destructors

NoneType()

NoneType::NoneType ( )

protected

Definition at line 50 of file qnonetype.cpp.

{
}

Functions

atomizedType()

ItemType::Ptr NoneType::atomizedType ( ) const

virtual

This can be thought to be a weird function for this type(none). There is no atomized type for none, perhaps the best from a conceptual perspective would be to return null.

This function returns BuiltinTypes::xsAnyAtomicType because the generic type checking code inserts an Atomizer in the AST when an error() function(or other node which has type none) is part of an operator expression(value/general comparison, arithmetics). The Atomizer returns the atomizedType() of its child, and by here returning xsAnyAtomicType, static operator lookup is postponed to runtime. Subsequently, expressions like error() works properly with other XPath expressions.

Implements QPatternist::ItemType.

Definition at line 94 of file qnonetype.cpp.

{
    return BuiltinTypes::xsAnyAtomicType;
}

cardinality()

Cardinality NoneType::cardinality ( ) const

virtual

Note

The semantical meaning of this type's cardinality can surely be discussed. The function is provided due to it being mandated by the SequenceType base class.

Returns

always Cardinality::zeroOrMore()

Implements QPatternist::SequenceType.

Definition at line 74 of file qnonetype.cpp.

{
    return Cardinality::zeroOrMore();
}

displayName()

QString NoneType::displayName ( const NamePool::Ptr &  np ) const

virtual

Returns

always "none". That is, no namespace prefix

Implements QPatternist::ItemType.

Definition at line 69 of file qnonetype.cpp.

{
    return QLatin1String("none");
}

isAtomicType()

bool NoneType::isAtomicType ( ) const

virtual

Returns

always false

Implements QPatternist::ItemType.

Definition at line 84 of file qnonetype.cpp.

{
    return false;
}

isNodeType()

bool NoneType::isNodeType ( ) const

virtual

Returns

always false

Implements QPatternist::ItemType.

Definition at line 89 of file qnonetype.cpp.

{
    return false;
}

itemMatches()

bool NoneType::itemMatches ( const Item &  item ) const

virtual

Parameters

item	the item that is to be matched. This is guaranteed by the caller to never be null.

Implements QPatternist::ItemType.

Definition at line 54 of file qnonetype.cpp.

{
    return false;
}

itemType()

ItemType::Ptr NoneType::itemType ( ) const

virtual

Note

The semantical meaning of this type's item type can surely be discussed. The function is provided due to it being mandated by the SequenceType base class.

Returns

always 'this' since NoneType is also an ItemType

Implements QPatternist::SequenceType.

Definition at line 79 of file qnonetype.cpp.

{
    return ItemType::Ptr(const_cast<NoneType *>(this));
}

operator|()

const ItemType & NoneType::operator| ( const ItemType &  other ) const

virtual

Returns

always other. The none type can be thought as disappearing when attempting to find the union of it and another type.

Reimplemented from QPatternist::ItemType.

Definition at line 64 of file qnonetype.cpp.

{
    return other;
}

xdtSuperType()

ItemType::Ptr NoneType::xdtSuperType ( ) const

virtual

Returns

always item()

Implements QPatternist::ItemType.

Definition at line 99 of file qnonetype.cpp.

{
    return BuiltinTypes::item;
}

xdtTypeMatches()

bool NoneType::xdtTypeMatches ( const ItemType::Ptr &  other ) const

virtual

Returns true if other matches this type. That is, if other is equal to this type or a subtype of this type.

For instance this statements evaluates to true:

BuiltinTypes::xsAnyAtomicType->xdtTypeMatches(BuiltinTypes::xsString);

but this evaluates to false:

BuiltinTypes::attribute->xdtTypeMatches(BuiltinTypes::node);

Parameters

other

the other ItemType that is to be matched. This is guaranteed by the caller to never be null.

Implements QPatternist::ItemType.

Definition at line 59 of file qnonetype.cpp.

{
    return *this == *t;
}

Friends and Related Functions

CommonSequenceTypes

friend class CommonSequenceTypes

friend

Definition at line 146 of file qnonetype_p.h.

---

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

• /src/xmlpatterns/type/qnonetype_p.h
• /src/xmlpatterns/type/qnonetype.cpp