QgsExpression::NodeLiteral Class Reference

#include <qgsexpression.h>

Inheritance diagram for QgsExpression::NodeLiteral:

Public Member Functions
	NodeLiteral (const QVariant &value)
virtual void	accept (Visitor &v) const override
	Support the visitor pattern. More...
virtual Node *	clone () const override
	Generate a clone of this node. More...
virtual QString	dump () const override
	Abstract virtual dump method. More...
virtual QVariant	eval (QgsExpression *parent, const QgsExpressionContext *context) override
	Abstract virtual eval method Errors are reported to the parent. More...
virtual bool	needsGeometry () const override
	Abstract virtual method which returns if the geometry is required to evaluate this expression. More...
virtual NodeType	nodeType () const override
	Abstract virtual that returns the type of this node. More...
virtual bool	prepare (QgsExpression *parent, const QgsExpressionContext *context) override
	Abstract virtual preparation method Errors are reported to the parent. More...
virtual QStringList	referencedColumns () const override
	Abstract virtual method which returns a list of columns required to evaluate this node. More...
QVariant	value () const
	The value of the literal. More...
Public Member Functions inherited from QgsExpression::Node
virtual	~Node ()
virtual Q_DECL_DEPRECATED QVariant	eval (QgsExpression *parent, const QgsFeature *f)
	Abstract virtual eval method Errors are reported to the parent. More...
virtual Q_DECL_DEPRECATED bool	prepare (QgsExpression *parent, const QgsFields &fields)
	Abstract virtual preparation method Errors are reported to the parent. More...

Protected Attributes
QVariant	mValue

Detailed Description

Definition at line 1337 of file qgsexpression.h.

Constructor & Destructor Documentation

NodeLiteral()

QgsExpression::NodeLiteral::NodeLiteral ( const QVariant &  value )

inline

Definition at line 1340 of file qgsexpression.h.

Member Function Documentation

accept()

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

inlineoverridevirtual

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.

Implements QgsExpression::Node.

Definition at line 1354 of file qgsexpression.h.

clone()

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

overridevirtual

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.

Implements QgsExpression::Node.

Definition at line 4809 of file qgsexpression.cpp.

dump()

QString QgsExpression::NodeLiteral::dump ( ) const

overridevirtual

Abstract virtual dump method.

Returns

An expression which represents this node as string

Implements QgsExpression::Node.

Definition at line 4789 of file qgsexpression.cpp.

eval()

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

overridevirtual

Abstract virtual eval method Errors are reported to the parent.

Note

added in QGIS 2.12

Reimplemented from QgsExpression::Node.

Definition at line 4774 of file qgsexpression.cpp.

needsGeometry()

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

inlineoverridevirtual

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

Implements QgsExpression::Node.

Definition at line 1353 of file qgsexpression.h.

nodeType()

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

inlineoverridevirtual

Abstract virtual that returns the type of this node.

Returns

The type of this node

Implements QgsExpression::Node.

Definition at line 1347 of file qgsexpression.h.

prepare()

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

overridevirtual

Abstract virtual preparation method Errors are reported to the parent.

Note

added in QGIS 2.12

Reimplemented from QgsExpression::Node.

Definition at line 4781 of file qgsexpression.cpp.

referencedColumns()

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

inlineoverridevirtual

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

Implements QgsExpression::Node.

Definition at line 1352 of file qgsexpression.h.

value()

QVariant QgsExpression::NodeLiteral::value ( ) const

inline

The value of the literal.

Definition at line 1345 of file qgsexpression.h.

Member Data Documentation

mValue

QVariant QgsExpression::NodeLiteral::mValue

protected

Definition at line 1358 of file qgsexpression.h.

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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