QGIS API Documentation
2.14.0-Essen
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#include <qgsexpression.h>
Public Member Functions | |
NodeColumnRef (const QString &name) | |
virtual void | accept (Visitor &v) const override |
Support the visitor pattern. More... | |
virtual Node * | clone () const override |
Generate a clone of this node. More... | |
virtual QString | dump () const override |
Abstract virtual dump method. More... | |
virtual QVariant | eval (QgsExpression *parent, const QgsExpressionContext *context) override |
Abstract virtual eval method Errors are reported to the parent. More... | |
QString | name () const |
The name of the column. More... | |
virtual bool | needsGeometry () const override |
Abstract virtual method which returns if the geometry is required to evaluate this expression. More... | |
virtual NodeType | nodeType () const override |
Abstract virtual that returns the type of this node. More... | |
virtual bool | prepare (QgsExpression *parent, const QgsExpressionContext *context) override |
Abstract virtual preparation method Errors are reported to the parent. More... | |
virtual QStringList | referencedColumns () const override |
Abstract virtual method which returns a list of columns required to evaluate this node. More... | |
Public Member Functions inherited from QgsExpression::Node | |
virtual | ~Node () |
virtual Q_DECL_DEPRECATED QVariant | eval (QgsExpression *parent, const QgsFeature *f) |
Abstract virtual eval method Errors are reported to the parent. More... | |
virtual Q_DECL_DEPRECATED bool | prepare (QgsExpression *parent, const QgsFields &fields) |
Abstract virtual preparation method Errors are reported to the parent. More... | |
Protected Attributes | |
int | mIndex |
QString | mName |
Definition at line 979 of file qgsexpression.h.
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inline |
Definition at line 982 of file qgsexpression.h.
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inlineoverridevirtual |
Support the visitor pattern.
For any implementation this should look like
C++:
v.visit( *this );
Python:
v.visit( self)
v | A visitor that visits this node. |
Implements QgsExpression::Node.
Definition at line 995 of file qgsexpression.h.
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overridevirtual |
Generate a clone of this node.
Make sure that the clone does not contain any information which is generated in prepare and context related. Ownership is transferred to the caller.
Implements QgsExpression::Node.
Definition at line 4288 of file qgsexpression.cpp.
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overridevirtual |
Abstract virtual dump method.
Implements QgsExpression::Node.
Definition at line 4283 of file qgsexpression.cpp.
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overridevirtual |
Abstract virtual eval method Errors are reported to the parent.
Reimplemented from QgsExpression::Node.
Definition at line 4249 of file qgsexpression.cpp.
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inline |
The name of the column.
Definition at line 985 of file qgsexpression.h.
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inlineoverridevirtual |
Abstract virtual method which returns if the geometry is required to evaluate this expression.
This needs to call needsGeometry()
recursively on any child nodes.
Implements QgsExpression::Node.
Definition at line 993 of file qgsexpression.h.
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inlineoverridevirtual |
Abstract virtual that returns the type of this node.
Implements QgsExpression::Node.
Definition at line 987 of file qgsexpression.h.
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overridevirtual |
Abstract virtual preparation method Errors are reported to the parent.
Reimplemented from QgsExpression::Node.
Definition at line 4263 of file qgsexpression.cpp.
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inlineoverridevirtual |
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.
Implements QgsExpression::Node.
Definition at line 992 of file qgsexpression.h.
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protected |
Definition at line 1000 of file qgsexpression.h.
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protected |
Definition at line 999 of file qgsexpression.h.