QGIS API Documentation
2.10.1-Pisa
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A abstract base class for defining QgsExpression functions. More...
#include <qgsexpression.h>
Public Member Functions | |
Function (const QString &fnname, int params, QString group, QString helpText=QString(), bool usesGeometry=false, QStringList referencedColumns=QStringList(), bool lazyEval=false, bool handlesNull=false) | |
virtual | ~Function () |
virtual QStringList | aliases () const |
Returns a list of possible aliases for the function. More... | |
virtual QVariant | func (const QVariantList &values, const QgsFeature *f, QgsExpression *parent)=0 |
QString | group () |
The group the function belongs to. More... | |
virtual bool | handlesNull () const |
const QString | helptext () |
The help text for the function. More... | |
bool | lazyEval () |
True if this function should use lazy evaluation. More... | |
QString | name () |
The name of the function. More... | |
bool | operator== (const Function &other) const |
int | params () |
The number of parameters this function takes. More... | |
virtual QStringList | referencedColumns () const |
bool | usesgeometry () |
Does this function use a geometry object. More... | |
A abstract base class for defining QgsExpression functions.
Definition at line 286 of file qgsexpression.h.
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Definition at line 289 of file qgsexpression.h.
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inlinevirtual |
Definition at line 307 of file qgsexpression.h.
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inlinevirtual |
Returns a list of possible aliases for the function.
These include other permissible names for the function, eg deprecated names.
Reimplemented in QgsExpression::StaticFunction.
Definition at line 321 of file qgsexpression.h.
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pure virtual |
Implemented in QgsExpression::StaticFunction.
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The group the function belongs to.
Definition at line 331 of file qgsexpression.h.
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inlinevirtual |
Definition at line 345 of file qgsexpression.h.
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The help text for the function.
Definition at line 333 of file qgsexpression.h.
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inline |
True if this function should use lazy evaluation.
Lazy evaluation functions take QgsExpression::Node objects rather than the node results when called. You can use node->eval(parent, feature) to evaluate the node and return the result Functions are non lazy default and will be given the node return value when called
Definition at line 326 of file qgsexpression.h.
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The name of the function.
Definition at line 310 of file qgsexpression.h.
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inline |
Definition at line 337 of file qgsexpression.h.
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inline |
The number of parameters this function takes.
Definition at line 312 of file qgsexpression.h.
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inlinevirtual |
Definition at line 328 of file qgsexpression.h.
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inline |
Does this function use a geometry object.
Definition at line 314 of file qgsexpression.h.