A predicate which is optimized for filter expressions that are of type xs:boolean. More...

#include <qtruthpredicate_p.h>

Inheritance diagram for QPatternist::TruthPredicate:

Public Functions
virtual ExpressionVisitorResult::Ptr	accept (const ExpressionVisitor::Ptr &visitor) const

virtual SequenceType::List	expectedOperandTypes () const

Item::Iterator::Ptr	map (const Item &item, const DynamicContext::Ptr &context) const

Item	mapToItem (const Item &item, const DynamicContext::Ptr &context) const

	TruthPredicate (const Expression::Ptr &sourceExpression, const Expression::Ptr &predicate)

Public Functions inherited from QPatternist::GenericPredicate
virtual QString	description () const

virtual Item::Iterator::Ptr	evaluateSequence (const DynamicContext::Ptr &context) const

virtual Item	evaluateSingleton (const DynamicContext::Ptr &context) const

virtual ID	id () const

Item	mapToItem (const Item &subject, const DynamicContext::Ptr &) const

virtual Properties	properties () const

virtual SequenceType::Ptr	staticType () const

Public Functions inherited from QPatternist::PairContainer
virtual bool	compressOperands (const StaticContext::Ptr &)

virtual Expression::List	operands () const

virtual void	setOperands (const Expression::List &operands)

Public Functions inherited from QPatternist::Expression
virtual const SourceLocationReflection *	actualReflection () const
	Returns `this`. More...

virtual void	announceFocusType (const ItemType::Ptr &itemType)

virtual Expression::Ptr	compress (const StaticContext::Ptr &context)

Properties	deepProperties () const
	Computes the union of properties for this Expression and all its descending children. More...

virtual Properties	dependencies () const

virtual bool	evaluateEBV (const DynamicContext::Ptr &context) const

virtual void	evaluateToSequenceReceiver (const DynamicContext::Ptr &context) const

virtual ItemType::Ptr	expectedContextItemType () const

	Expression ()

bool	has (const Property prop) const

bool	hasDependency (const Property prop) const

bool	is (const ID id) const

bool	isEvaluated () const

virtual QList< QExplicitlySharedDataPointer< OptimizationPass > >	optimizationPasses () const

virtual PatternPriority	patternPriority () const

const Expression::Ptr &	rewrite (const Expression::Ptr &to, const StaticContext::Ptr &context) const
	Rewrites this Expression to `to`, and return `to`. More...

virtual Expression::Ptr	typeCheck (const StaticContext::Ptr &context, const SequenceType::Ptr &reqType)

virtual	~Expression ()

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::CppCastingHelper< Expression >
const TCastTarget *	as () const

TCastTarget *	as ()

Public Functions inherited from QPatternist::SourceLocationReflection
virtual QSourceLocation	sourceLocation () const

	SourceLocationReflection ()

virtual	~SourceLocationReflection ()

Additional Inherited Members
Public Types inherited from QPatternist::Expression
typedef QExplicitlySharedDataPointer< const Expression >	ConstPtr
	A smart pointer wrapping `const` Expression instances. More...

enum	ID { IDBooleanValue = 1, IDCountFN, IDEmptyFN, IDExistsFN, IDExpressionSequence, IDGeneralComparison, IDIfThenClause, IDIgnorableExpression, IDIntegerValue, IDPositionFN, IDStringValue, IDValueComparison, IDRangeVariableReference, IDContextItem, IDUserFunctionCallsite, IDExpressionVariableReference, IDAttributeConstructor, IDUpperCaseFN, IDLowerCaseFN, IDFirstItemPredicate, IDEmptySequence, IDReturnOrderBy, IDLetClause, IDForClause, IDPath, IDNamespaceConstructor, IDArgumentReference, IDGenericPredicate, IDAxisStep, IDFloat, IDCombineNodes, IDUnresolvedVariableReference, IDCardinalityVerifier }

typedef QList< Expression::Ptr >	List

typedef QFlags< Property >	Properties

enum	Property { UseContextItem = 1, DisableElimination = 1 << 1, IsEvaluated = 1 << 2, DisableTypingDeduction = 1 << 3, EmptynessFollowsChild = 1 << 4, RewriteToEmptyOnEmpty = 1 << 5, RequiresFocus = 1 << 6, AffectsOrderOnly = 1 << 7, RequiresContextItem = (1 << 8) \| RequiresFocus, CreatesFocusForLast = 1 << 9, LastOperandIsCollation = 1 << 10, DependsOnLocalVariable = (1 << 11) \| DisableElimination, EvaluationCacheRedundant = (1 << 12), IsNodeConstructor = 1 << 13, RequiresCurrentItem = 1 << 14 }

typedef QExplicitlySharedDataPointer< Expression >	Ptr
	A smart pointer wrapping mutable Expression instances. More...

typedef ::QAbstractXmlForwardIterator< Expression::Ptr >	QAbstractXmlForwardIterator

typedef QVector< Expression::Ptr >	Vector

Static Public Functions inherited from QPatternist::GenericPredicate
static Expression::Ptr	create (const Expression::Ptr &sourceExpression, const Expression::Ptr &predicateExpression, const StaticContext::Ptr &context, const QSourceLocation &location)

static Expression::Ptr	createFirstItem (const Expression::Ptr &sourceExpression)

Static Public Functions inherited from QPatternist::Expression
static void	rewrite (Expression::Ptr &old, const Expression::Ptr &New, const StaticContext::Ptr &context)

Public Variables inherited from QSharedData
QAtomicInt	ref

Protected Functions inherited from QPatternist::GenericPredicate
	GenericPredicate (const Expression::Ptr &sourceExpression, const Expression::Ptr &predicate)

virtual ItemType::Ptr	newFocusType () const

Protected Functions inherited from QPatternist::PairContainer
	PairContainer (const Expression::Ptr &operand1, const Expression::Ptr &operand2)

Protected Functions inherited from QPatternist::Expression
void	typeCheckOperands (const StaticContext::Ptr &context)

Protected Functions inherited from QPatternist::CppCastingHelper< Expression >
	CppCastingHelper ()

Protected Variables inherited from QPatternist::PairContainer
Expression::Ptr	m_operand1

Expression::Ptr	m_operand2

Detailed Description

A predicate which is optimized for filter expressions that are of type xs:boolean.

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

Definition at line 70 of file qtruthpredicate_p.h.

Constructors and Destructors

◆ TruthPredicate()

TruthPredicate::TruthPredicate	(	const Expression::Ptr &	sourceExpression,
		const Expression::Ptr &	predicate
	)

Creates a TruthPredicate which filters the items from the sourceExpression through predicate.

This constructor is protected. The proper way to create predicates is via the static create() function.

Definition at line 52 of file qtruthpredicate.cpp.

                                                                : GenericPredicate(sourceExpression,
                                                                                     predicate)
 {
 }

Functions

◆ accept()

ExpressionVisitorResult::Ptr TruthPredicate::accept ( const ExpressionVisitor::Ptr & visitor ) const

virtual

Reimplemented from QPatternist::GenericPredicate.

Definition at line 66 of file qtruthpredicate.cpp.

Referenced by map().

 {
     return visitor->visit(this);
 }

◆ expectedOperandTypes()

SequenceType::List TruthPredicate::expectedOperandTypes ( ) const

virtual

Returns a list of Sequence Types, describing the type of each of the expression's operands. Hence, this function has a relationship to the operands() function:

- The lengths of the lists returned by expectedOperandTypes()
and operands() should always be equal in length, since one
cannot describe the type of a non-existent operand(and all
operands must have type information).
- A significant difference between the two functions is that while
the type of objects in the list returned by operands() may vary
between compilations/static context, simply because the particular
Expression is part of different XPath expressions, the
types in the list returned by expectedOperandTypes is always the same
since the function/operator signature never changes.

This function should not be confused with staticType(), which returns the static type of the expression itself, not its operands. The function call is an expression where this is clear: the type of the return value is not the same as the arguments' types. The static type of the operands supplied to the expression can be determined via the staticType() function of the instances returned by operands().

If the expression has no operands, an empty list should be returned.

Reimplemented from QPatternist::GenericPredicate.

Definition at line 58 of file qtruthpredicate.cpp.

Referenced by map().

 {
     SequenceType::List result;
     result.append(CommonSequenceTypes::ZeroOrMoreItems);
     result.append(CommonSequenceTypes::EBV);
     return result;
 }

◆ map()

Item::Iterator::Ptr QPatternist::TruthPredicate::map	(	const Item &	item,
		const DynamicContext::Ptr &	context
	)		const

inline

Definition at line 93 of file qtruthpredicate_p.h.

         {
             Q_ASSERT_X(false, Q_FUNC_INFO, "I don't expect this function to be called, for the same reasons as above.");
             if(m_operand2->evaluateEBV(context))
                 return makeSingletonIterator(item);
             else
                 return CommonValues::emptyIterator;
         }

◆ mapToItem()

Item QPatternist::TruthPredicate::mapToItem	(	const Item &	item,
		const DynamicContext::Ptr &	context
	)		const

inline

Definition at line 83 of file qtruthpredicate_p.h.

         {
             Q_ASSERT_X(false, Q_FUNC_INFO, "This is practically dead code because it never gets called in GenericPredicate, "
                                            "which binds to its own mapToItem for completely legitime reasons.");
             if(m_operand2->evaluateEBV(context))
                 return item;
             else
                 return Item();
         }

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

/src/xmlpatterns/expr/qtruthpredicate_p.h
/src/xmlpatterns/expr/qtruthpredicate.cpp

Public Functions

Additional Inherited Members