QGIS API Documentation  3.13.0-Master (7f54853aae)
Public Types | Public Member Functions | List of all members
QgsExpressionNodeUnaryOperator Class Reference

A unary node is either negative as in boolean (not) or as in numbers (minus). More...

#include <qgsexpressionnodeimpl.h>

Inheritance diagram for QgsExpressionNodeUnaryOperator:
Inheritance graph
[legend]

Public Types

enum  UnaryOperator { uoNot, uoMinus }
 list of unary operators More...
 
- Public Types inherited from QgsExpressionNode
enum  NodeType {
  ntUnaryOperator, ntBinaryOperator, ntInOperator, ntFunction,
  ntLiteral, ntColumnRef, ntCondition, ntIndexOperator
}
 Known node types. More...
 

Public Member Functions

 QgsExpressionNodeUnaryOperator (QgsExpressionNodeUnaryOperator::UnaryOperator op, QgsExpressionNode *operand)
 A node unary operator is modifying the value of operand by negating it with op. More...
 
 ~QgsExpressionNodeUnaryOperator () override
 
QgsExpressionNodeclone () 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 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...
 
QgsExpressionNodeUnaryOperator::UnaryOperator op () const
 Returns the unary operator. More...
 
QgsExpressionNodeoperand () const
 Returns the node the operator will operate upon. 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 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 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 unary node is either negative as in boolean (not) or as in numbers (minus).

Definition at line 27 of file qgsexpressionnodeimpl.h.

Member Enumeration Documentation

◆ UnaryOperator

list of unary operators

Note
if any change is made here, the definition of QgsExpression::UnaryOperatorText[] must be adapted.
Enumerator
uoNot 
uoMinus 

Definition at line 35 of file qgsexpressionnodeimpl.h.

Constructor & Destructor Documentation

◆ QgsExpressionNodeUnaryOperator()

QgsExpressionNodeUnaryOperator::QgsExpressionNodeUnaryOperator ( QgsExpressionNodeUnaryOperator::UnaryOperator  op,
QgsExpressionNode operand 
)
inline

A node unary operator is modifying the value of operand by negating it with op.

Definition at line 44 of file qgsexpressionnodeimpl.h.

◆ ~QgsExpressionNodeUnaryOperator()

QgsExpressionNodeUnaryOperator::~QgsExpressionNodeUnaryOperator ( )
inlineoverride

Definition at line 48 of file qgsexpressionnodeimpl.h.

Member Function Documentation

◆ clone()

QgsExpressionNode * QgsExpressionNodeUnaryOperator::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 161 of file qgsexpressionnodeimpl.cpp.

◆ dump()

QString QgsExpressionNodeUnaryOperator::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 125 of file qgsexpressionnodeimpl.cpp.

◆ evalNode()

QVariant QgsExpressionNodeUnaryOperator::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 88 of file qgsexpressionnodeimpl.cpp.

◆ isStatic()

bool QgsExpressionNodeUnaryOperator::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 168 of file qgsexpressionnodeimpl.cpp.

◆ needsGeometry()

bool QgsExpressionNodeUnaryOperator::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 156 of file qgsexpressionnodeimpl.cpp.

◆ nodes()

QList< const QgsExpressionNode * > QgsExpressionNodeUnaryOperator::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 148 of file qgsexpressionnodeimpl.cpp.

◆ nodeType()

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

Gets the type of this node.

Returns
The type of this node

Implements QgsExpressionNode.

Definition at line 115 of file qgsexpressionnodeimpl.cpp.

◆ op()

QgsExpressionNodeUnaryOperator::UnaryOperator QgsExpressionNodeUnaryOperator::op ( ) const
inline

Returns the unary operator.

Definition at line 53 of file qgsexpressionnodeimpl.h.

◆ operand()

QgsExpressionNode* QgsExpressionNodeUnaryOperator::operand ( ) const
inline

Returns the node the operator will operate upon.

Definition at line 58 of file qgsexpressionnodeimpl.h.

◆ prepareNode()

bool QgsExpressionNodeUnaryOperator::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 120 of file qgsexpressionnodeimpl.cpp.

◆ referencedColumns()

QSet< QString > QgsExpressionNodeUnaryOperator::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 133 of file qgsexpressionnodeimpl.cpp.

◆ referencedFunctions()

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

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

Implements QgsExpressionNode.

Definition at line 143 of file qgsexpressionnodeimpl.cpp.

◆ referencedVariables()

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

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

Implements QgsExpressionNode.

Definition at line 138 of file qgsexpressionnodeimpl.cpp.

◆ text()

QString QgsExpressionNodeUnaryOperator::text ( ) const

Returns a the name of this operator without the operands.

I.e. "NOT" or "-"

Definition at line 173 of file qgsexpressionnodeimpl.cpp.


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