/************************************************************************
* This file has been generated automatically from *
* *
* src/core/expression/qgsexpressionfunction.h *
* *
* Do not edit manually ! Edit header and run scripts/sipify.pl again *
************************************************************************/
class QgsExpressionFunction
{
%Docstring
A abstract base class for defining QgsExpression functions.
%End
%TypeHeaderCode
#include "qgsexpressionfunction.h"
%End
public:
class Parameter
{
%Docstring
Represents a single parameter passed to a function.
.. versionadded:: 2.16
%End
%TypeHeaderCode
#include "qgsexpressionfunction.h"
%End
public:
Parameter( const QString &name,
bool optional = false,
const QVariant &defaultValue = QVariant(),
bool isSubExpression = false );
%Docstring
Constructor for Parameter.
:param name: parameter name, used when named parameter are specified in an expression
:param optional: set to ``True`` if parameter should be optional
:param defaultValue: default value to use for optional parameters
:param isSubExpression: set to ``True`` if this parameter is a sub-expression
%End
QString name() const;
%Docstring
Returns the name of the parameter.
%End
bool optional() const;
%Docstring
Returns ``True`` if the parameter is optional.
%End
QVariant defaultValue() const;
%Docstring
Returns the default value for the parameter.
%End
bool isSubExpression() const;
%Docstring
Returns ``True`` if parameter argument is a separate sub-expression, and
should not be checked while determining referenced columns for the expression.
.. versionadded:: 3.2
%End
bool operator==( const QgsExpressionFunction::Parameter &other ) const;
};
typedef QList< QgsExpressionFunction::Parameter > ParameterList;
QgsExpressionFunction( const QString &fnname,
int params,
const QString &group,
const QString &helpText = QString(),
bool lazyEval = false,
bool handlesNull = false,
bool isContextual = false );
%Docstring
Constructor for function which uses unnamed parameters
%End
QgsExpressionFunction( const QString &fnname,
int params,
const QStringList &groups,
const QString &helpText = QString(),
bool lazyEval = false,
bool handlesNull = false,
bool isContextual = false );
%Docstring
Constructor for function which uses unnamed parameters and group list
.. versionadded:: 3.0
%End
QgsExpressionFunction( const QString &fnname,
const QgsExpressionFunction::ParameterList ¶ms,
const QString &group,
const QString &helpText = QString(),
bool lazyEval = false,
bool handlesNull = false,
bool isContextual = false );
%Docstring
Constructor for function which uses named parameter list.
.. versionadded:: 2.16
%End
QgsExpressionFunction( const QString &fnname,
const QgsExpressionFunction::ParameterList ¶ms,
const QStringList &groups,
const QString &helpText = QString(),
bool lazyEval = false,
bool handlesNull = false,
bool isContextual = false );
%Docstring
Constructor for function which uses named parameter list and group list.
.. versionadded:: 3.0
%End
virtual ~QgsExpressionFunction();
QString name() const;
%Docstring
The name of the function.
%End
int params() const;
%Docstring
The number of parameters this function takes.
%End
int minParams() const;
%Docstring
The minimum number of parameters this function takes.
%End
const QgsExpressionFunction::ParameterList ¶meters() const;
%Docstring
Returns the list of named parameters for the function, if set.
.. versionadded:: 2.16
%End
virtual bool usesGeometry( const QgsExpressionNodeFunction *node ) const;
%Docstring
Does this function use a geometry object.
%End
virtual QStringList aliases() const;
%Docstring
Returns a list of possible aliases for the function. These include
other permissible names for the function, e.g., deprecated names.
:return: list of known aliases
.. versionadded:: 2.9
%End
bool lazyEval() const;
%Docstring
``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.
%End
virtual bool isStatic( const QgsExpressionNodeFunction *node, QgsExpression *parent, const QgsExpressionContext *context ) const;
%Docstring
Will be called during prepare to determine if the function is static.
A function is static if it will return the same value for every feature with different
attributes and/or geometry.
By default this will return ``True``, if all arguments that have been passed to the function
are also static.
.. versionadded:: 3.0
%End
virtual bool prepare( const QgsExpressionNodeFunction *node, QgsExpression *parent, const QgsExpressionContext *context ) const;
%Docstring
This will be called during the prepare step() of an expression if it is not static.
This can be used by functions to do any preparation steps that might help to speedup the upcoming
evaluation.
.. versionadded:: 3.0
%End
virtual QSet<QString> referencedColumns( const QgsExpressionNodeFunction *node ) const;
%Docstring
Returns a set of field names which are required for this function.
May contain QgsFeatureRequest.AllAttributes to signal that all
attributes are required.
If in doubt this will return more fields than strictly required.
.. versionadded:: 3.0
%End
bool isContextual() const;
%Docstring
Returns whether the function is only available if provided by a QgsExpressionContext object.
.. versionadded:: 2.12
%End
virtual bool isDeprecated() const;
%Docstring
Returns ``True`` if the function is deprecated and should not be presented as a valid option
to users in expression builders.
.. versionadded:: 3.0
%End
QString group() const;
%Docstring
Returns the first group which the function belongs to.
.. note::
consider using groups() instead, as some functions naturally belong in multiple groups
%End
QStringList groups() const;
%Docstring
Returns a list of the groups the function belongs to.
.. seealso:: :py:func:`group`
.. versionadded:: 3.0
%End
const QString helpText() const;
%Docstring
The help text for the function.
%End
virtual QVariant func( const QVariantList &values, const QgsExpressionContext *context, QgsExpression *parent, const QgsExpressionNodeFunction *node ) = 0;
%Docstring
Returns result of evaluating the function.
:param values: list of values passed to the function
:param context: context expression is being evaluated against
:param parent: parent expression
:param node: expression node
:return: result of function
%End
virtual QVariant run( QgsExpressionNode::NodeList *args, const QgsExpressionContext *context, QgsExpression *parent, const QgsExpressionNodeFunction *node );
%Docstring
Evaluates the function, first evaluating all required arguments before passing them to the
function's func() method.
%End
bool operator==( const QgsExpressionFunction &other ) const;
virtual bool handlesNull() const;
%Docstring
Returns ``True`` if the function handles NULL values in arguments by itself, and the default
NULL value handling should be skipped.
%End
protected:
static bool allParamsStatic( const QgsExpressionNodeFunction *node, QgsExpression *parent, const QgsExpressionContext *context );
%Docstring
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.
.. versionadded:: 3.0
%End
};
/************************************************************************
* This file has been generated automatically from *
* *
* src/core/expression/qgsexpressionfunction.h *
* *
* Do not edit manually ! Edit header and run scripts/sipify.pl again *
************************************************************************/