#include <MFnExpression.h>

Class Description

Expression function set.

This class is used to create, edit, and query expression nodes.

Examples:: AbcBullet/MayaUtility.cpp, and AbcExport/MayaUtility.cpp.

Inheritance diagram for MFnExpression:

Public Types
enum	UnitConversion { kAll, kNone, kAngularOnly }
	Unit conversion modes. More...

Public Types inherited from MFnDependencyNode
enum	MAttrClass { kLocalDynamicAttr = 1, kNormalAttr, kExtensionAttr, kInvalidAttr }
	Specifies the scope of the attribute. More...

enum	MdgTimerState { kTimerOff, kTimerOn, kTimerUninitialized, kTimerInvalidState }
	Possible states for the node's timer. More...

enum	MdgTimerMetric { kTimerMetric_callback, kTimerMetric_compute, kTimerMetric_dirty, kTimerMetric_draw, kTimerMetric_fetch, kTimerMetric_callbackViaAPI, kTimerMetric_callbackNotViaAPI, kTimerMetric_computeDuringCallback, kTimerMetric_computeNotDuringCallback, kTimerMetrics }
	The different timer metrics which can be queried. More...

enum	MdgTimerType { kTimerType_self, kTimerType_inclusive, kTimerType_count, kTimerTypes }
	The types of timers which can be queried. More...

Public Member Functions
virtual MFn::Type	type () const
	Function set type. More...

virtual	~MFnExpression ()
	Destructor.

	MFnExpression ()
	Default constructor.

	MFnExpression (MObject &object, MStatus *ReturnStatus=NULL)
	Constructor. More...

MObject	create (const MString &expression, MObject &object=MObject::kNullObj, MStatus *ReturnStatus=NULL)
	This method creates and returns a dependency node for a given expression. More...

MString	expression (MStatus *ReturnStatus=NULL)
	Gets the expression string for this expression node. More...

MStatus	setExpression (const MString &expression)
	Sets the expression string for this expression node. More...

MStatus	getDefaultObject (MObject &object)
	Gets the "default" object for the expression. More...

MStatus	setDefaultObject (MObject &object)
	Sets the "default" object for the expression. More...

bool	isAnimated (MStatus *ReturnStatus=NULL)
	If this is true, then the expression will be evaluated whenever time changes, regardless of whether the other inputs have changed. More...

MStatus	setAnimated (bool value=false)
	Sets the way in which the expression is evaluated. More...

MStatus	evaluate (MDoubleArray &result)
	Evaluate this expression and return the result. More...

UnitConversion	unitConversion (MStatus *ReturnStatus=NULL) const
	Get the unit conversion status for the expression node. More...

MStatus	setUnitConversion (UnitConversion conversion)
	Set the unit conversion options for the expression node. More...

	MFnExpression (const MObject &object, MStatus *ReturnStatus=NULL)
	Constructor. More...

MStatus	getExpression (MString &expression)
	NO SCRIPT SUPPORT. More...

Public Member Functions inherited from MFnDependencyNode
virtual	~MFnDependencyNode ()
	Destructor.

	MFnDependencyNode ()
	Default constructor.

	MFnDependencyNode (MObject &object, MStatus *ReturnStatus=NULL)
	Constructor. More...

MObject	create (const MTypeId &typeId, MStatus *ReturnStatus=NULL)
	Creates a new dependency node with the given type tag. More...

MObject	create (const MTypeId &typeId, const MString &name, MStatus *ReturnStatus=NULL)
	Creates a new dependency node with the given type tag. More...

MObject	create (const MString &type, MStatus *ReturnStatus=NULL)
	Creates a new dependency node with the given type. More...

MObject	create (const MString &type, const MString &name, MStatus *ReturnStatus=NULL)
	Creates a new dependency node with the given type. More...

MTypeId	typeId (MStatus *ReturnStatus=NULL) const
	Returns the type id of this node. More...

MString	typeName (MStatus *ReturnStatus=NULL) const
	Returns the type name of this node. More...

MString	name (MStatus *ReturnStatus=NULL) const
	Returns the name of this node. More...

MString	absoluteName (MStatus *ReturnStatus=NULL) const
	Returns the absolute name of this node. More...

MString	pluginName (MStatus *ReturnStatus=NULL) const
	Returns the name of the plug-in this MFnDependendencyNode was defined in. More...

MString	setName (const MString &name, bool createNamespace=false, MStatus *ReturnStatus=NULL)
	Sets the name of this node. More...

MUuid	uuid (MStatus *ReturnStatus=NULL) const
	Returns the node's UUID. More...

void	setUuid (const MUuid &uuid, MStatus *ReturnStatus=NULL)
	Sets the node's UUID. More...

MStatus	getConnections (MPlugArray &array) const
	Get all of the current connections to this node as an array of plugs. More...

unsigned int	attributeCount (MStatus *ReturnStatus=NULL) const
	Returns the number of attributes that this node has. More...

MObject	attribute (unsigned int index, MStatus *ReturnStatus=NULL) const
	Finds the attribute of this node at the given index. More...

MObject	reorderedAttribute (unsigned int index, MStatus *ReturnStatus=NULL) const
	Some nodes, such as the various animCurve nodes, require that their attributes be set in a specific order for proper operation. More...

MObject	attribute (const MString &attrName, MStatus *ReturnStatus=NULL) const
	Finds the attribute of this node that has the given name. More...

MAttrClass	attributeClass (const MObject &attr, MStatus *ReturnStatus=NULL) const
	Returns the class (normal, dynamic, extension) of the specified attribute. More...

MStatus	getAffectedAttributes (const MObject &attr, MObjectArray &affectedAttributes) const
	Returns an array of attributes that are affected by the attribute passed in. More...

MStatus	getAffectedByAttributes (const MObject &attr, MObjectArray &affectedByAttributes) const
	Returns an array of attributes that affect the attribute passed in, attr. More...

MPlug	findPlug (const MObject &attr, bool wantNetworkedPlug, MStatus *ReturnStatus=NULL) const
	Attempt to find a plug for the given attribute. More...

MPlug	findPlug (const MString &attrName, bool wantNetworkedPlug, MStatus *ReturnStatus=NULL) const
	Attempt to find a plug for the given attribute. More...

MPlug	findPlug (const MObject &attr, MStatus *ReturnStatus=NULL) const
	This method is obsolete. More...

MPlug	findPlug (const MString &attrName, MStatus *ReturnStatus=NULL) const
	This method is obsolete. More...

MStatus	addAttribute (const MObject &attr)
	Add a new dynamic attibute to this node. More...

MStatus	removeAttribute (const MObject &attr)
	Remove a dynamic attribute from a node. More...

MPxNode *	userNode (MStatus *ReturnStatus=NULL) const
	If the function set's node is a plug-in node, then this method will extract the MPxNode pointer from it. More...

bool	isFromReferencedFile (MStatus *ReturnStatus=NULL) const
	Indicates whether or not this node came from a referenced file. More...

bool	isShared (MStatus *ReturnStatus=NULL) const
	Indicates whether or not this node is shared. More...

bool	isTrackingEdits (MStatus *ReturnStatus=NULL) const
	Returns whether or not edits on the given node are being tracked by the generalized edit system. More...

bool	hasUniqueName (MStatus *ReturnStatus=NULL) const
	Indicates whether or not this node's name is unique within the scene. More...

MString	parentNamespace (MStatus *ReturnStatus=NULL) const
	Returns the name of the namespace in which this node resides. More...

bool	isLocked (MStatus *ReturnStatus=NULL) const
	Indicates whether or not this node is locked. More...

MStatus	setLocked (bool locked)
	Locks or unlocks this node. More...

bool	isNewAttribute (const MObject &attr, MStatus *ReturnStatus=NULL) const
	Indicates whether or not the specified attribute was added to this node within the current scene. More...

MStatus	setFlag (unsigned int flag, bool state)
	Sets the state of the specified flag for the node. More...

bool	isFlagSet (unsigned int flag, MStatus *ReturnStatus=NULL) const
	Retrieves the current state of the specified flag for a node. More...

bool	isDefaultNode (MStatus *ReturnStatus=NULL) const
	Returns true if the node is a default node. More...

MStatus	setDoNotWrite (bool flag)
	Use this method to mark the "do not write" state of this node. More...

bool	canBeWritten (MStatus *ReturnStatus=NULL) const
	Returns the do not write state of the node. More...

bool	hasAttribute (const MString &name, MStatus *ReturnStatus=NULL) const
	Returns true if the node already has an attribute with the given name. More...

MObject	getAliasAttr (bool force, MStatus *ReturnStatus=NULL)
	Returns the node's alias attribute, which is a special attribute used to store information about the node's attribute aliases. More...

bool	setAlias (const MString &alias, const MString &name, const MPlug &plug, bool add=true, MStatus *ReturnStatus=NULL)
	Sets or removes an alias (i.e. More...

bool	findAlias (const MString &alias, MObject &attrObj, MStatus *ReturnStatus=NULL) const
	Retrieves the attribute with the given alias. More...

bool	getAliasList (MStringArray &strArray, MStatus *ReturnStatus=NULL)
	Returns a list of all attribute aliases for this node. More...

MString	plugsAlias (const MPlug &plug, MStatus *ReturnStatus=NULL)
	Returns the alias for the plug's attribute or the empty string if that attribute has no alias. More...

MStatus	setIcon (const MString &filename)
	Associates a custom icon with the node for display in the Maya UI. More...

MString	icon (MStatus *ReturnStatus=NULL) const
	Returns the custom icon filename associated with the node. More...

MStatus	getExternalContent (MExternalContentInfoTable &table) const
	Returns the external content (files) that this node depends on. More...

MStatus	addExternalContentForFileAttr (MExternalContentInfoTable &table, const MObject &attr) const
	Adds content info to the specified table from a file path attribute. More...

MStatus	setExternalContentForFileAttr (const MObject &attr, const MExternalContentLocationTable &table)
	Sets content info in the specified attribute from the table. More...

MStatus	setExternalContent (const MExternalContentLocationTable &table)
	Changes the location of external content. More...

MString	setName (const MString &name, MStatus *ReturnStatus)
	OBSOLETE FUNCTION, NO SCRIPT SUPPORT. More...

	MFnDependencyNode (const MObject &object, MStatus *ReturnStatus=NULL)
	NO SCRIPT SUPPORT. More...

bool	getPlugsAlias (const MPlug &plug, MString &aliasName, MStatus *ReturnStatus=NULL)
	NO SCRIPT SUPPORT. More...

virtual const adsk::Data::Associations *	metadata (MStatus *ReturnStatus=NULL) const
	This method is not available in Python. More...

virtual MStatus	setMetadata (const adsk::Data::Associations &)
	This method is not available in Python. More...

virtual MStatus	deleteMetadata ()
	This method is not available in Python. More...

virtual MStatus	validateMetadata (MString &errors) const
	This method is not available in Python. More...

MStatus	dgTimerOn ()
	Indicates that this node should collect DG timing data whenever DG timing is enabled. More...

MStatus	dgTimerOff ()
	Indicates that this node should no longer collect DG timing data when DG timing is enabled. More...

MdgTimerState	dgTimerQueryState (MStatus *ReturnStatus=NULL)
	The function returns the current on/off state of the node's timer. More...

MStatus	dgTimerReset ()
	The function resets the dependency graph timers and counters for this node to zero. More...

double	dgTimer (const MdgTimerMetric timerMetric, const MdgTimerType timerType, MStatus *ReturnStatus=NULL) const
	The function returns the specified timer value for the current node. More...

MStatus	dgCallbacks (const MdgTimerType type, MStringArray &callbackName, MDoubleArray &value)
	Node callbacks that occur when timing is enabled get logged with the node and can be queried via this method. More...

MStatus	dgCallbackIds (const MdgTimerType type, const MString &callbackName, MCallbackIdArray &callbackId, MDoubleArray &value)
	This method provides a further breakdown of the per-callback time returned via dgCallbacks() by returning the data on a per-callbackId basis. More...

MStatus	addAttribute (const MObject &attr, MAttrClass type)
	This method is obsolete. More...

MStatus	removeAttribute (const MObject &attr, MAttrClass type)
	This method is obsolete. More...

Public Member Functions inherited from MFnBase
virtual	~MFnBase ()
	Class Destructor. More...

bool	hasObj (MFn::Type) const
	Determines whether or not the Function Set is compatible with the specified Maya Object within the API RTTI system. More...

bool	hasObj (const MObject &) const
	Determines whether or not the Function Set is compatible with the specified Maya Object within the API RTTI system. More...

MObject	object (MStatus *ReturnStatus=NULL) const
	Returns the MObject that is attached to the Function Set. More...

virtual MStatus	setObject (MObject &object)
	Attaches the Function Set to the specified Maya Object. More...

virtual MStatus	setObject (const MObject &object)
	NO SCRIPT SUPPORT. More...

Protected Member Functions
virtual const char *	className () const
	Class name. More...

Additional Inherited Members
Static Public Member Functions inherited from MFnDependencyNode
static MString	classification (const MString &nodeTypeName)
	Retrieves the classification string for a node type. More...

static unsigned int	allocateFlag (const MString pluginName, MStatus *ReturnStatus=NULL)
	Allocates a node flag for sole use by the caller. More...

static MStatus	deallocateFlag (const MString pluginName, unsigned int flag)
	Deallocates a node flag which was previously allocated by a call to allocateFlag. More...

static MStatus	deallocateAllFlags (const MString pluginName)
	Deallocates all of the node flags which are currently allocated to the specified plugin. More...

static void	enableDGTiming (bool enable)
	Globally enables or disables the DG node timing mechanism. More...

Static Public Member Functions inherited from MFnBase
static const char *	className ()
	Returns the name of this class. More...

Member Enumeration Documentation

enum UnitConversion

Unit conversion modes.

Enumerator
kAll	Convert all units.
kNone	Do not do any unit conversion.
kAngularOnly	Only convert angular units.

Constructor & Destructor Documentation

MFnExpression	(	MObject &	object,
		MStatus *	ReturnStatus = `NULL`
	)

Constructor.

Class constructor that initializes the function set to the given MObject.

Parameters

[in]	object	The MObject to attach the function set to
[out]	ReturnStatus	the return status

Status Codes:

MS::kSuccess if the function set is successfully attached
MS::kInvalidParameter if the MObject does not represent a valid Maya object or if the function set is not allowed to attach to this MObject

MFnExpression	(	const MObject &	object,
		MStatus *	ReturnStatus = `NULL`
	)

Constructor.

Class constructor that initializes the function set to the given MObject.

Parameters

[in]	object	The MObject to attach the function set to
[out]	ReturnStatus	the return status

Status Codes:

MS::kSuccess if the function set is successfully attached
MS::kInvalidParameter if the MObject does not represent a valid Maya object or if the function set is not allowed to attach to this MObject

Member Function Documentation

MFn::Type type ( ) const

virtual

Function set type.

Return the class type : MFn::kExpression.

Reimplemented from MFnDependencyNode.

OPENMAYA_MAJOR_NAMESPACE_OPEN const char * className ( ) const

protectedvirtual

Class name.

Return the class name : "MFnExpression".

Reimplemented from MFnDependencyNode.

MObject create	(	const MString &	expression,
		MObject &	object = `MObject::kNullObj`,
		MStatus *	ReturnStatus = `NULL`
	)

This method creates and returns a dependency node for a given expression.

A default object can be specified, but if it is not specified in the expression string then the expression string values will be used.

If the expression string is of the form "objectName.attribute = ... " then the default object parameter is not needed. If you supply a default object in this case, then it will be ignored.

If the expression has no default object then you must supply one. For example, if the expression is of the form "attribute = ...", then you must supply a default object.

Parameters

[in]	expression	The expression string
[in]	object	The default object (optional - see above)
[out]	ReturnStatus	Status code

Returns: The expression node

Status Codes:

MS::kSuccess
MS::kLicenseFailure application not licensed for attempted operation
MS::kFailure

MString expression ( MStatus * ReturnStatus = NULL )

Gets the expression string for this expression node.

Parameters

[out] ReturnStatus Status code. See below.

Returns: The expression string

Status Codes:

MS::kSuccess
MS::kFailure

MStatus setExpression ( const MString & expression )

Sets the expression string for this expression node.

Parameters

[in] expression The expression string

Returns: Status Code

Status Codes:

MS::kSuccess
MS::kFailure

MStatus getDefaultObject ( MObject & object )

Gets the "default" object for the expression.

Not all expressions have a default object. If there is no default object for the expression, the object will be set to MObject::kNullObject and the return status will indicate success. This is a completely legal case that the calling code should check for before blindly using the returned object.

Parameters

[out] object storage for the default object

Returns: Status Code

Status Codes:

MS::kSuccess
MS::kFailure

MStatus setDefaultObject ( MObject & object )

Sets the "default" object for the expression.

This allows the expression writer to not type the object name for frequently-used objects.

This method will only work for expression strings in which the object name is not specified.

Parameters

[in] object the object to be set

Returns: Status Code

Status Codes:

MS::kSuccess
MS::kFailure

bool isAnimated ( MStatus * ReturnStatus = NULL )

If this is true, then the expression will be evaluated whenever time changes, regardless of whether the other inputs have changed.

If it is false (the default) , then the expression will only be evaluated if one or more of the inputs change.

Note, if 'time' or 'frame' are inputs, then the expression will act as if this was set to true.

Parameters

[out] ReturnStatus Status code

Returns

true expression will be evaluated whenever time changes
false

Status Codes:

MS::kSuccess
MS::kFailure

MStatus setAnimated ( bool value = false )

Sets the way in which the expression is evaluated.

If this is true, then the expression will be evaluated whenever time changes, regardless of whether the other inputs have changed.

If it is false (the default) , then the expression will only be evaluated if one or more of the inputs change.

Note, if 'time' or 'frame' are inputs, then the expression will act as if this was set to true.

Parameters

[in] value sets the objects evaluation type

Returns: Status Code

Status Codes:

MS::kSuccess
MS::kFailure

MStatus evaluate ( MDoubleArray & result )

Evaluate this expression and return the result.

Parameters

[out] result the value of the expression

Returns: Status code

Status Codes:

MS::kSuccess
MS::kFailure

MFnExpression::UnitConversion unitConversion ( MStatus * ReturnStatus = NULL ) const

Get the unit conversion status for the expression node.

Parameters

[out] ReturnStatus Status code

Returns: The unit conversion state for this node

Status Codes:

MS::kSuccess operation successful
MS::kFailure function set does not have a valid object

MStatus setUnitConversion ( UnitConversion conversion )

Set the unit conversion options for the expression node.

Parameters

[in] conversion unit conversion state for this node

Returns: Status code

Status Codes:

MS::kSuccess operation successful
MS::kFailure function set does not have a valid object

MStatus getExpression ( MString & expression )

NO SCRIPT SUPPORT.

Gets the expression string for this expression node.

Python Notes

This method is not supported in Python. Please see the one which returns a string

Parameters

[in] expression The expression string

Returns: Status code

Status Codes:

MS::kSuccess
MS::kFailure

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

MFnExpression.h
MFnExpression.cpp

MFnExpression Class Reference

Class Description

Public Types

Public Member Functions

Protected Member Functions

Additional Inherited Members

Member Enumeration Documentation

Constructor & Destructor Documentation

Member Function Documentation