Class: QgsScopedExpressionFunction

class qgis.core.QgsScopedExpressionFunction

Bases: QgsExpressionFunction

Expression function for use within a QgsExpressionContextScope. This differs from a standard QgsExpression.Function in that it requires an implemented clone() method.

New in version 2.12.

QgsScopedExpressionFunction(fnname: str, params: int, group: str, helpText: str = ‘’, usesGeometry: bool = False, referencedColumns: Iterable[str] = set(), lazyEval: bool = False, handlesNull: bool = False, isContextual: bool = True) Create a new QgsScopedExpressionFunction

New in version 2.12.

QgsScopedExpressionFunction(fnname: str, params: Iterable[QgsExpressionFunction.Parameter], group: str, helpText: str = ‘’, usesGeometry: bool = False, referencedColumns: Iterable[str] = set(), lazyEval: bool = False, handlesNull: bool = False, isContextual: bool = True) Create a new QgsScopedExpressionFunction using named parameters.

New in version 3.0.

QgsScopedExpressionFunction(QgsScopedExpressionFunction)

Methods

allParamsStatic

This will return True if all the params for the provided function node are static within the constraints imposed by the context within the given parent.

clone

Returns a clone of the function.

func

param values

isStatic

param node

referencedColumns

param node

usesGeometry

param node

allParamsStatic(node: QgsExpressionNodeFunction, parent: QgsExpression, context: QgsExpressionContext)bool

This will return True if all the params for the provided function node are static within the constraints imposed by the context within the given parent.

This can be used as callback for custom implementations of subclasses. It is the default for implementation for StaticFunction.isStatic.

New in version 3.0.

clone(self)QgsScopedExpressionFunction

Returns a clone of the function.

Return type

QgsScopedExpressionFunction

func(self, values: Iterable[Any], context: QgsExpressionContext, parent: QgsExpression, node: QgsExpressionNodeFunction)Any
Parameters
Return type

Any

isStatic(self, node: QgsExpressionNodeFunction, parent: QgsExpression, context: QgsExpressionContext)bool
Parameters
Return type

bool

referencedColumns(self, node: QgsExpressionNodeFunction)Set[str]
Parameters

node (QgsExpressionNodeFunction) –

Return type

Set[str]

usesGeometry(self, node: QgsExpressionNodeFunction)bool
Parameters

node (QgsExpressionNodeFunction) –

Return type

bool