QgsExpressionNodeBinaryOperator Class Reference

A binary expression operator, which operates on two values. More...

#include <qgsexpressionnodeimpl.h>

Inheritance diagram for QgsExpressionNodeBinaryOperator:

Public Types
enum	BinaryOperator {   boOr , boAnd , boEQ , boNE ,   boLE , boGE , boLT , boGT ,   boRegexp , boLike , boNotLike , boILike ,   boNotILike , boIs , boIsNot , boPlus ,   boMinus , boMul , boDiv , boIntDiv ,   boMod , boPow , boConcat }
	list of binary operators More...
Public Types inherited from QgsExpressionNode
enum	NodeType {   ntUnaryOperator , ntBinaryOperator , ntInOperator , ntFunction ,   ntLiteral , ntColumnRef , ntCondition , ntIndexOperator ,   ntBetweenOperator }
	Known node types. More...

Public Member Functions
	QgsExpressionNodeBinaryOperator (QgsExpressionNodeBinaryOperator::BinaryOperator op, QgsExpressionNode *opLeft, QgsExpressionNode *opRight)
	Binary combination of the left and the right with op. More...
	~QgsExpressionNodeBinaryOperator () override
QgsExpressionNode *	clone () const override
	Generate a clone of this node. More...
QString	dump () const override
	Dump this node into a serialized (part) of an expression. More...
QVariant	evalNode (QgsExpression *parent, const QgsExpressionContext *context) override
	Abstract virtual eval method Errors are reported to the parent. More...
bool	isStatic (QgsExpression *parent, const QgsExpressionContext *context) const override
	Returns true if this node can be evaluated for a static value. More...
bool	leftAssociative () const
	Returns true if the operator is left-associative. More...
bool	needsGeometry () const override
	Abstract virtual method which returns if the geometry is required to evaluate this expression. More...
QList< const QgsExpressionNode * >	nodes () const override
	Returns a list of all nodes which are used in this expression. More...
QgsExpressionNode::NodeType	nodeType () const override
	Gets the type of this node. More...
QgsExpressionNodeBinaryOperator::BinaryOperator	op () const
	Returns the binary operator. More...
QgsExpressionNode *	opLeft () const
	Returns the node to the left of the operator. More...
QgsExpressionNode *	opRight () const
	Returns the node to the right of the operator. More...
int	precedence () const
	Returns the precedence index for the operator. More...
bool	prepareNode (QgsExpression *parent, const QgsExpressionContext *context) override
	Abstract virtual preparation method Errors are reported to the parent. More...
QSet< QString >	referencedColumns () const override
	Abstract virtual method which returns a list of columns required to evaluate this node. More...
QSet< QString >	referencedFunctions () const override
	Returns a set of all functions which are used in this expression. More...
QSet< QString >	referencedVariables () const override
	Returns a set of all variables which are used in this expression. More...
QString	text () const
	Returns a the name of this operator without the operands. More...
Public Member Functions inherited from QgsExpressionNode
virtual	~QgsExpressionNode ()=default
QVariant	cachedStaticValue () const
	Returns the node's static cached value. More...
virtual QgsExpressionNode *	clone () const =0
	Generate a clone of this node. More...
virtual QString	dump () const =0
	Dump this node into a serialized (part) of an expression. More...
const QgsExpressionNode *	effectiveNode () const
	Returns a reference to the simplest node which represents this node, after any compilation optimizations have been applied. More...
QVariant	eval (QgsExpression *parent, const QgsExpressionContext *context)
	Evaluate this node with the given context and parent. More...
bool	hasCachedStaticValue () const
	Returns true if the node can be replaced by a static cached value. More...
virtual bool	isStatic (QgsExpression *parent, const QgsExpressionContext *context) const =0
	Returns true if this node can be evaluated for a static value. More...
virtual bool	needsGeometry () const =0
	Abstract virtual method which returns if the geometry is required to evaluate this expression. More...
virtual QList< const QgsExpressionNode * >	nodes () const =0
	Returns a list of all nodes which are used in this expression. More...
virtual QgsExpressionNode::NodeType	nodeType () const =0
	Gets the type of this node. More...
bool	prepare (QgsExpression *parent, const QgsExpressionContext *context)
	Prepare this node for evaluation. More...
virtual QSet< QString >	referencedColumns () const =0
	Abstract virtual method which returns a list of columns required to evaluate this node. More...
virtual QSet< QString >	referencedFunctions () const =0
	Returns a set of all functions which are used in this expression. More...
virtual QSet< QString >	referencedVariables () const =0
	Returns a set of all variables which are used in this expression. More...

Additional Inherited Members
Public Attributes inherited from QgsExpressionNode
int	parserFirstColumn = 0
	First column in the parser this node was found. More...
int	parserFirstLine = 0
	First line in the parser this node was found. More...
int	parserLastColumn = 0
	Last column in the parser this node was found. More...
int	parserLastLine = 0
	Last line in the parser this node was found. More...
Protected Member Functions inherited from QgsExpressionNode
	QgsExpressionNode ()=default
	Constructor. More...
	QgsExpressionNode (const QgsExpressionNode &other)
	Copy constructor. More...
void	cloneTo (QgsExpressionNode *target) const
	Copies the members of this node to the node provided in target. More...
QgsExpressionNode &	operator= (const QgsExpressionNode &other)
	Assignment operator. More...
Protected Attributes inherited from QgsExpressionNode
QVariant	mCachedStaticValue
	Contains the static, precalculated value for the node if mHasCachedValue is true. More...
std::unique_ptr< QgsExpressionNode >	mCompiledSimplifiedNode
	Contains a compiled node which represents a simplified version of this node as a result of compilation optimizations. More...
bool	mHasCachedValue = false
	true if the node has a static, precalculated value. More...

Detailed Description

A binary expression operator, which operates on two values.

Definition at line 99 of file qgsexpressionnodeimpl.h.

Member Enumeration Documentation

BinaryOperator

enum QgsExpressionNodeBinaryOperator::BinaryOperator

list of binary operators

Note

if any change is made here, the definition of QgsExpression::BinaryOperatorText[] must be adapted.

Enumerator
boOr
boAnd
boEQ	=
boNE	<>
boLE	<=
boGE	>=
boLT	<
boGT	‍
boRegexp
boLike
boNotLike
boILike
boNotILike
boIs
boIsNot
boPlus
boMinus
boMul
boDiv
boIntDiv
boMod
boPow
boConcat

Definition at line 107 of file qgsexpressionnodeimpl.h.

Constructor & Destructor Documentation

QgsExpressionNodeBinaryOperator()

QgsExpressionNodeBinaryOperator::QgsExpressionNodeBinaryOperator ( QgsExpressionNodeBinaryOperator::BinaryOperator  op, QgsExpressionNode *  opLeft, QgsExpressionNode *  opRight  )

inline

Binary combination of the left and the right with op.

Definition at line 144 of file qgsexpressionnodeimpl.h.

~QgsExpressionNodeBinaryOperator()

QgsExpressionNodeBinaryOperator::~QgsExpressionNodeBinaryOperator ( )

inlineoverride

Definition at line 149 of file qgsexpressionnodeimpl.h.

Member Function Documentation

clone()

QgsExpressionNode * QgsExpressionNodeBinaryOperator::clone ( ) const

overridevirtual

Generate a clone of this node.

Ownership is transferred to the caller.

Returns

a deep copy of this node.

Implements QgsExpressionNode.

Definition at line 831 of file qgsexpressionnodeimpl.cpp.

dump()

QString QgsExpressionNodeBinaryOperator::dump ( ) const

overridevirtual

Dump this node into a serialized (part) of an expression.

The returned expression does not necessarily literally match the original expression, it's just guaranteed to behave the same way.

Implements QgsExpressionNode.

Definition at line 769 of file qgsexpressionnodeimpl.cpp.

evalNode()

QVariant QgsExpressionNodeBinaryOperator::evalNode ( QgsExpression *  parent, const QgsExpressionContext *  context  )

overridevirtual

Abstract virtual eval method Errors are reported to the parent.

Since

QGIS 3.0

Implements QgsExpressionNode.

Definition at line 202 of file qgsexpressionnodeimpl.cpp.

isStatic()

bool QgsExpressionNodeBinaryOperator::isStatic ( QgsExpression *  parent, const QgsExpressionContext *  context  ) const

overridevirtual

Returns true if this node can be evaluated for a static value.

This is used during the prepare() step and in case it returns true, the value of this node will already be evaluated and the result cached (and therefore not re-evaluated in subsequent calls to eval()). In case this returns true, prepareNode() will never be called.

Since

QGIS 3.0

Implements QgsExpressionNode.

Definition at line 838 of file qgsexpressionnodeimpl.cpp.

leftAssociative()

bool QgsExpressionNodeBinaryOperator::leftAssociative

(

)

const

Returns true if the operator is left-associative.

Definition at line 733 of file qgsexpressionnodeimpl.cpp.

needsGeometry()

bool QgsExpressionNodeBinaryOperator::needsGeometry ( ) const

overridevirtual

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 QgsExpressionNode.

Definition at line 826 of file qgsexpressionnodeimpl.cpp.

nodes()

QList< const QgsExpressionNode * > QgsExpressionNodeBinaryOperator::nodes ( ) const

overridevirtual

Returns a list of all nodes which are used in this expression.

Note

not available in Python bindings

Since

QGIS 3.2

Implements QgsExpressionNode.

Definition at line 818 of file qgsexpressionnodeimpl.cpp.

nodeType()

QgsExpressionNode::NodeType QgsExpressionNodeBinaryOperator::nodeType ( ) const

overridevirtual

Gets the type of this node.

Returns

The type of this node

Implements QgsExpressionNode.

Definition at line 675 of file qgsexpressionnodeimpl.cpp.

op()

QgsExpressionNodeBinaryOperator::BinaryOperator QgsExpressionNodeBinaryOperator::op ( ) const

inline

Returns the binary operator.

Definition at line 162 of file qgsexpressionnodeimpl.h.

opLeft()

QgsExpressionNode * QgsExpressionNodeBinaryOperator::opLeft ( ) const

inline

Returns the node to the left of the operator.

See also

opRight()

Definition at line 168 of file qgsexpressionnodeimpl.h.

opRight()

QgsExpressionNode * QgsExpressionNodeBinaryOperator::opRight ( ) const

inline

Returns the node to the right of the operator.

See also

opLeft()

Definition at line 174 of file qgsexpressionnodeimpl.h.

precedence()

int QgsExpressionNodeBinaryOperator::precedence

(

)

const

Returns the precedence index for the operator.

Higher values have higher precedence.

Definition at line 687 of file qgsexpressionnodeimpl.cpp.

prepareNode()

bool QgsExpressionNodeBinaryOperator::prepareNode ( QgsExpression *  parent, const QgsExpressionContext *  context  )

overridevirtual

Abstract virtual preparation method Errors are reported to the parent.

Since

QGIS 3.0

Implements QgsExpressionNode.

Definition at line 680 of file qgsexpressionnodeimpl.cpp.

referencedColumns()

QSet< QString > QgsExpressionNodeBinaryOperator::referencedColumns ( ) const

overridevirtual

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.

Warning

If the expression has been prepared via a call to QgsExpression::prepare(), or a call to QgsExpressionNode::prepare() for a node has been made, then some nodes in the expression may have been determined to evaluate to a static pre-calculatable value. In this case the results will omit attribute indices which are used by these pre-calculated nodes, regardless of their actual referenced columns. If you are seeking to use these functions to introspect an expression you must take care to do this with an unprepared expression node.

Returns

A list of columns required to evaluate this expression

Implements QgsExpressionNode.

Definition at line 800 of file qgsexpressionnodeimpl.cpp.

referencedFunctions()

QSet< QString > QgsExpressionNodeBinaryOperator::referencedFunctions ( ) const

overridevirtual

Returns a set of all functions which are used in this expression.

Note

In contrast to the referencedColumns() function this method is not affected by any previous calls to QgsExpressionNode::prepare().

Implements QgsExpressionNode.

Definition at line 813 of file qgsexpressionnodeimpl.cpp.

referencedVariables()

QSet< QString > QgsExpressionNodeBinaryOperator::referencedVariables ( ) const

overridevirtual

Returns a set of all variables which are used in this expression.

Note

In contrast to the referencedColumns() function this method is not affected by any previous calls to QgsExpressionNode::prepare().

Implements QgsExpressionNode.

Definition at line 808 of file qgsexpressionnodeimpl.cpp.

text()

QString QgsExpressionNodeBinaryOperator::text

(

)

const

Returns a the name of this operator without the operands.

I.e. "AND", "OR", ...

Definition at line 1974 of file qgsexpressionnodeimpl.cpp.

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

• /build/qgis-3.28.0+99sid/src/core/expression/qgsexpressionnodeimpl.h
• /build/qgis-3.28.0+99sid/src/core/expression/qgsexpressionnodeimpl.cpp