QGIS API Documentation  3.9.0-Master (224899f119)
Public Member Functions | List of all members
QgsExpressionNodeIndexOperator Class Reference

A indexing expression operator, which allows use of square brackets [] to reference map and array items. More...

#include <qgsexpressionnodeimpl.h>

Inheritance diagram for QgsExpressionNodeIndexOperator:
Inheritance graph
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Public Member Functions

 QgsExpressionNodeIndexOperator (QgsExpressionNode *container, QgsExpressionNode *index)
 Constructor for QgsExpressionNodeIndexOperator. More...
 
 ~QgsExpressionNodeIndexOperator () override
 
QgsExpressionNodeclone () const override
 Generate a clone of this node. More...
 
QgsExpressionNodecontainer () const
 Returns the container node, representing an array or map value. 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...
 
QgsExpressionNodeindex () const
 Returns the index node, representing an array element index or map key. More...
 
bool isStatic (QgsExpression *parent, const QgsExpressionContext *context) const override
 Returns true if this node can be evaluated for a static value. 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...
 
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...
 
- Public Member Functions inherited from QgsExpressionNode
virtual ~QgsExpressionNode ()=default
 
QVariant eval (QgsExpression *parent, const QgsExpressionContext *context)
 Evaluate this node with the given context and parent. More...
 
bool prepare (QgsExpression *parent, const QgsExpressionContext *context)
 Prepare this node for evaluation. More...
 

Additional Inherited Members

- Public Types inherited from QgsExpressionNode
enum  NodeType {
  ntUnaryOperator, ntBinaryOperator, ntInOperator, ntFunction,
  ntLiteral, ntColumnRef, ntCondition, ntIndexOperator
}
 Known node types. More...
 
- 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
void cloneTo (QgsExpressionNode *target) const
 Copies the members of this node to the node provided in target. More...
 

Detailed Description

A indexing expression operator, which allows use of square brackets [] to reference map and array items.

Since
QGIS 3.6

Definition at line 214 of file qgsexpressionnodeimpl.h.

Constructor & Destructor Documentation

◆ QgsExpressionNodeIndexOperator()

QgsExpressionNodeIndexOperator::QgsExpressionNodeIndexOperator ( QgsExpressionNode container,
QgsExpressionNode index 
)
inline

Constructor for QgsExpressionNodeIndexOperator.

Definition at line 221 of file qgsexpressionnodeimpl.h.

◆ ~QgsExpressionNodeIndexOperator()

QgsExpressionNodeIndexOperator::~QgsExpressionNodeIndexOperator ( )
inlineoverride

Definition at line 225 of file qgsexpressionnodeimpl.h.

Member Function Documentation

◆ clone()

QgsExpressionNode * QgsExpressionNodeIndexOperator::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 1650 of file qgsexpressionnodeimpl.cpp.

◆ container()

QgsExpressionNode* QgsExpressionNodeIndexOperator::container ( ) const
inline

Returns the container node, representing an array or map value.

See also
index()

Definition at line 231 of file qgsexpressionnodeimpl.h.

◆ dump()

QString QgsExpressionNodeIndexOperator::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 1617 of file qgsexpressionnodeimpl.cpp.

◆ evalNode()

QVariant QgsExpressionNodeIndexOperator::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 1569 of file qgsexpressionnodeimpl.cpp.

◆ index()

QgsExpressionNode* QgsExpressionNodeIndexOperator::index ( ) const
inline

Returns the index node, representing an array element index or map key.

See also
container()

Definition at line 237 of file qgsexpressionnodeimpl.h.

◆ isStatic()

bool QgsExpressionNodeIndexOperator::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 1657 of file qgsexpressionnodeimpl.cpp.

◆ needsGeometry()

bool QgsExpressionNodeIndexOperator::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 1645 of file qgsexpressionnodeimpl.cpp.

◆ nodes()

QList< const QgsExpressionNode * > QgsExpressionNodeIndexOperator::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 1637 of file qgsexpressionnodeimpl.cpp.

◆ nodeType()

QgsExpressionNode::NodeType QgsExpressionNodeIndexOperator::nodeType ( ) const
overridevirtual

Gets the type of this node.

Returns
The type of this node

Implements QgsExpressionNode.

Definition at line 1605 of file qgsexpressionnodeimpl.cpp.

◆ prepareNode()

bool QgsExpressionNodeIndexOperator::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 1610 of file qgsexpressionnodeimpl.cpp.

◆ referencedColumns()

QSet< QString > QgsExpressionNodeIndexOperator::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.

Returns
A list of columns required to evaluate this expression

Implements QgsExpressionNode.

Definition at line 1622 of file qgsexpressionnodeimpl.cpp.

◆ referencedFunctions()

QSet< QString > QgsExpressionNodeIndexOperator::referencedFunctions ( ) const
overridevirtual

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

Implements QgsExpressionNode.

Definition at line 1632 of file qgsexpressionnodeimpl.cpp.

◆ referencedVariables()

QSet< QString > QgsExpressionNodeIndexOperator::referencedVariables ( ) const
overridevirtual

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

Implements QgsExpressionNode.

Definition at line 1627 of file qgsexpressionnodeimpl.cpp.


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