The PreconditionNode evaluates a script condition before ticking its child. More...

#include <script_precondition.h>

Inheritance diagram for BT::PreconditionNode:

Collaboration diagram for BT::PreconditionNode:

Public Member Functions
	PreconditionNode (const std::string &name, const NodeConfig &config)

	PreconditionNode (const PreconditionNode &)=delete

PreconditionNode &	operator= (const PreconditionNode &)=delete

	PreconditionNode (PreconditionNode &&)=delete

PreconditionNode &	operator= (PreconditionNode &&)=delete

Public Member Functions inherited from BT::DecoratorNode
	DecoratorNode (const std::string &name, const NodeConfig &config)

	DecoratorNode (const DecoratorNode &)=delete

DecoratorNode &	operator= (const DecoratorNode &)=delete

	DecoratorNode (DecoratorNode &&)=delete

DecoratorNode &	operator= (DecoratorNode &&)=delete

void	setChild (TreeNode *child)

const TreeNode *	child () const

TreeNode *	child ()

virtual void	halt () override
	The method used to interrupt the execution of this node.

void	haltChild ()
	Same as resetChild()

virtual NodeType	type () const override

NodeStatus	executeTick () override
	The method that should be used to invoke tick() and setStatus();.

void	resetChild ()

Public Member Functions inherited from BT::TreeNode
	TreeNode (std::string name, NodeConfig config)
	TreeNode main constructor.

	TreeNode (const TreeNode &other)=delete

TreeNode &	operator= (const TreeNode &other)=delete

	TreeNode (TreeNode &&other) noexcept

TreeNode &	operator= (TreeNode &&other) noexcept

virtual BT::NodeStatus	executeTick ()
	The method that should be used to invoke tick() and setStatus();.

void	haltNode ()

bool	isHalted () const

NodeStatus	status () const

const std::string &	name () const
	Name of the instance, not the type.

BT::NodeStatus	waitValidStatus ()

virtual NodeType	type () const =0

StatusChangeSubscriber	subscribeToStatusChange (StatusChangeCallback callback)
	subscribeToStatusChange is used to attach a callback to a status change. When StatusChangeSubscriber goes out of scope (it is a shared_ptr) the callback is unsubscribed automatically.

void	setPreTickFunction (PreTickCallback callback)

void	setPostTickFunction (PostTickCallback callback)

void	setTickMonitorCallback (TickMonitorCallback callback)

uint16_t	UID () const

const std::string &	fullPath () const

const std::string &	registrationName () const
	registrationName is the ID used by BehaviorTreeFactory to create an instance.

const NodeConfig &	config () const

template<typename T >
Result	getInput (const std::string &key, T &destination) const

template<typename T >
Expected< Timestamp >	getInputStamped (const std::string &key, T &destination) const
	getInputStamped is similar to getInput(dey, destination), but it returns also the Timestamp object, that can be used to check if a value was updated and when.

template<typename T >
Expected< T >	getInput (const std::string &key) const

template<typename T >
Expected< StampedValue< T > >	getInputStamped (const std::string &key) const

template<typename T >
Result	setOutput (const std::string &key, const T &value)
	setOutput modifies the content of an Output port

AnyPtrLocked	getLockedPortContent (const std::string &key)
	getLockedPortContent should be used when:

StringView	getRawPortValue (const std::string &key) const

void	emitWakeUpSignal ()
	Notify that the tree should be ticked again()

bool	requiresWakeUp () const

Static Public Member Functions
static PortsList	providedPorts ()

Static Public Member Functions inherited from BT::TreeNode
static bool	isBlackboardPointer (StringView str, StringView *stripped_pointer=nullptr)
	Check a string and return true if it matches the pattern: {...}.

static StringView	stripBlackboardPointer (StringView str)

static Expected< StringView >	getRemappedKey (StringView port_name, StringView remapped_port)

template<class DerivedT , typename... ExtraArgs>
static std::unique_ptr< TreeNode >	Instantiate (const std::string &name, const NodeConfig &config, ExtraArgs... args)

Additional Inherited Members
Public Types inherited from BT::TreeNode
typedef std::shared_ptr< TreeNode >	Ptr

using	StatusChangeSignal = Signal< TimePoint, const TreeNode &, NodeStatus, NodeStatus >

using	StatusChangeSubscriber = StatusChangeSignal::Subscriber

using	StatusChangeCallback = StatusChangeSignal::CallableFunction

using	PreTickCallback = std::function< NodeStatus(TreeNode &)>

using	PostTickCallback = std::function< NodeStatus(TreeNode &, NodeStatus)>

using	TickMonitorCallback = std::function< void(TreeNode &, NodeStatus, std::chrono::microseconds)>

Protected Types inherited from BT::TreeNode
using	PreScripts = std::array< ScriptFunction, size_t(PreCond::COUNT_)>

using	PostScripts = std::array< ScriptFunction, size_t(PostCond::COUNT_)>

Protected Member Functions inherited from BT::TreeNode
NodeConfig &	config ()

virtual BT::NodeStatus	tick ()=0
	Method to be implemented by the user.

void	resetStatus ()
	Set the status to IDLE.

void	setRegistrationID (StringView ID)

void	setWakeUpInstance (std::shared_ptr< WakeUpSignal > instance)

void	modifyPortsRemapping (const PortsRemapping &new_remapping)

void	setStatus (NodeStatus new_status)
	setStatus changes the status of the node. it will throw if you try to change the status to IDLE, because your parent node should do that, not the user!

PreScripts &	preConditionsScripts ()

PostScripts &	postConditionsScripts ()

template<typename T >
T	parseString (const std::string &str) const

Protected Attributes inherited from BT::DecoratorNode
TreeNode *	child_node_

Detailed Description

The PreconditionNode evaluates a script condition before ticking its child.

If the script in the "if" port returns true, the child is ticked. If the script returns false, the node returns the status specified in the "else" port (FAILURE by default).

Once the child starts (returns RUNNING), subsequent ticks will continue executing the child without re-evaluating the precondition until completion.

Example usage:

<Precondition if="A > B && color != BLUE" else="FAILURE"> <SomeAction> </Precondition>

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

include/behaviortree_cpp/decorators/script_precondition.h

Public Member Functions

Static Public Member Functions

Additional Inherited Members

Detailed Description