#include <qgsexpression.h>

Inheritance diagram for QgsExpression::Node:

[legend]

Public Member Functions
virtual	~Node ()

virtual void	accept (Visitor &v) const =0
	Support the visitor pattern. More...

virtual Node *	clone () const =0
	Generate a clone of this node. More...

virtual QString	dump () const =0
	Abstract virtual dump method. More...

virtual Q_DECL_DEPRECATED QVariant	eval (QgsExpression parent, const QgsFeature f)
	Abstract virtual eval method Errors are reported to the parent. More...

virtual QVariant	eval (QgsExpression parent, const QgsExpressionContext context)
	Abstract virtual eval method Errors are reported to the parent. More...

virtual bool	needsGeometry () const =0
	Abstract virtual method which returns if the geometry is required to evaluate this expression. More...

virtual NodeType	nodeType () const =0
	Abstract virtual that returns the type of this node. More...

virtual Q_DECL_DEPRECATED bool	prepare (QgsExpression *parent, const QgsFields &fields)
	Abstract virtual preparation method Errors are reported to the parent. More...

virtual bool	prepare (QgsExpression parent, const QgsExpressionContext context)
	Abstract virtual preparation method Errors are reported to the parent. More...

virtual QStringList	referencedColumns () const =0
	Abstract virtual method which returns a list of columns required to evaluate this node. More...

Detailed Description

Definition at line 922 of file qgsexpression.h.

Constructor & Destructor Documentation

◆ ~Node()

virtual QgsExpression::Node::~Node ( )

inlinevirtual

Definition at line 925 of file qgsexpression.h.

Member Function Documentation

◆ accept()

virtual void QgsExpression::Node::accept ( Visitor & v ) const

pure virtual

Support the visitor pattern.

For any implementation this should look like

C++:

v.visit( *this );

Python:

v.visit( self)

Parameters

v	A visitor that visits this node.

Implemented in QgsExpression::NodeCondition, QgsExpression::NodeColumnRef, QgsExpression::NodeLiteral, QgsExpression::NodeFunction, QgsExpression::NodeInOperator, QgsExpression::NodeBinaryOperator, and QgsExpression::NodeUnaryOperator.

◆ clone()

virtual Node* QgsExpression::Node::clone ( ) const

pure virtual

Generate a clone of this node.

Make sure that the clone does not contain any information which is generated in prepare and context related. Ownership is transferred to the caller.

Returns: a deep copy of this node.

Implemented in QgsExpression::NodeCondition, QgsExpression::NodeColumnRef, QgsExpression::NodeLiteral, QgsExpression::NodeFunction, QgsExpression::NodeInOperator, QgsExpression::NodeBinaryOperator, and QgsExpression::NodeUnaryOperator.

◆ dump()

virtual QString QgsExpression::Node::dump ( ) const

pure virtual

Abstract virtual dump method.

Returns: An expression which represents this node as string

Implemented in QgsExpression::NodeCondition, QgsExpression::NodeColumnRef, QgsExpression::NodeLiteral, QgsExpression::NodeFunction, QgsExpression::NodeInOperator, QgsExpression::NodeBinaryOperator, and QgsExpression::NodeUnaryOperator.

◆ eval() [1/2]

QVariant QgsExpression::Node::eval	(	QgsExpression *	parent,
		const QgsFeature *	f
	)

virtual

Abstract virtual eval method Errors are reported to the parent.

Deprecated:: use QgsExpressionContext variant instead

Definition at line 5283 of file qgsexpression.cpp.

◆ eval() [2/2]

QVariant QgsExpression::Node::eval	(	QgsExpression *	parent,
		const QgsExpressionContext *	context
	)

virtual

Abstract virtual eval method Errors are reported to the parent.

Note: added in QGIS 2.12

Reimplemented in QgsExpression::NodeCondition, QgsExpression::NodeColumnRef, QgsExpression::NodeLiteral, QgsExpression::NodeFunction, QgsExpression::NodeInOperator, QgsExpression::NodeBinaryOperator, and QgsExpression::NodeUnaryOperator.

Definition at line 5290 of file qgsexpression.cpp.

◆ needsGeometry()

virtual bool QgsExpression::Node::needsGeometry ( ) const

pure virtual

Abstract virtual method which returns if the geometry is required to evaluate this expression.

This needs to call needsGeometry() recursively on any child nodes.

Returns: true if a geometry is required to evaluate this expression

Implemented in QgsExpression::NodeCondition, QgsExpression::NodeColumnRef, QgsExpression::NodeLiteral, QgsExpression::NodeFunction, QgsExpression::NodeInOperator, QgsExpression::NodeBinaryOperator, and QgsExpression::NodeUnaryOperator.

◆ nodeType()

virtual NodeType QgsExpression::Node::nodeType ( ) const

pure virtual

Abstract virtual that returns the type of this node.

Returns: The type of this node

Implemented in QgsExpression::NodeCondition, QgsExpression::NodeColumnRef, QgsExpression::NodeLiteral, QgsExpression::NodeFunction, QgsExpression::NodeInOperator, QgsExpression::NodeBinaryOperator, and QgsExpression::NodeUnaryOperator.

◆ prepare() [1/2]

bool QgsExpression::Node::prepare	(	QgsExpression *	parent,
		const QgsFields &	fields
	)

virtual

Abstract virtual preparation method Errors are reported to the parent.

Deprecated:: use QgsExpressionContext variant instead

Definition at line 5302 of file qgsexpression.cpp.

◆ prepare() [2/2]

bool QgsExpression::Node::prepare	(	QgsExpression *	parent,
		const QgsExpressionContext *	context
	)

virtual

Abstract virtual preparation method Errors are reported to the parent.

Note: added in QGIS 2.12

Reimplemented in QgsExpression::NodeCondition, QgsExpression::NodeColumnRef, QgsExpression::NodeLiteral, QgsExpression::NodeFunction, QgsExpression::NodeInOperator, QgsExpression::NodeBinaryOperator, and QgsExpression::NodeUnaryOperator.

Definition at line 5308 of file qgsexpression.cpp.

◆ referencedColumns()

virtual QStringList QgsExpression::Node::referencedColumns ( ) const

pure virtual

Abstract virtual method which returns a list of columns required to evaluate this node.

When reimplementing this, you need to return any column that is required to evaluate this node and in addition recursively collect all the columns required to evaluate child nodes.

Returns: A list of columns required to evaluate this expression

Implemented in QgsExpression::NodeCondition, QgsExpression::NodeColumnRef, QgsExpression::NodeLiteral, QgsExpression::NodeFunction, QgsExpression::NodeInOperator, QgsExpression::NodeBinaryOperator, and QgsExpression::NodeUnaryOperator.

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

/tmp/buildd/qgis-2.18.21+99unstable/src/core/qgsexpression.h
/tmp/buildd/qgis-2.18.21+99unstable/src/core/qgsexpression.cpp

Public Member Functions

Detailed Description

Constructor & Destructor Documentation

◆ ~Node()

Member Function Documentation

◆ accept()

◆ clone()

◆ dump()

◆ eval() [1/2]

◆ eval() [2/2]

◆ needsGeometry()

◆ nodeType()

◆ prepare() [1/2]

◆ prepare() [2/2]

◆ referencedColumns()