#include "behaviortree_cpp/bt_factory.h"

using namespace BT;

// To demonstrate how to pass arguments by reference, we

// use a simple non-copyable object

class NoCopyObj

{

public:

NoCopyObj(int val) : _value(val)

{}

NoCopyObj(const NoCopyObj&) = delete;

NoCopyObj& operator=(const NoCopyObj&) = delete;

int value()

{

return _value;

}

private:

int _value = 0;

};

/*

* Sometimes, it is convenient to pass additional (static) arguments to a Node.

* If these parameters are known at compilation time or at deployment-time

* and they don't change at run-time, input ports are probably overkill and cumbersome.

*

* This tutorial demonstrates two possible ways to initialize a custom node with

* additional arguments.

*/

// Action_A has a different constructor than the default one.

class Action_A : public SyncActionNode

{

public:

// additional arguments passed to the constructor

Action_A(const std::string& name, const NodeConfig& config, int arg_int,

std::string arg_str, NoCopyObj& nc)

: SyncActionNode(name, config), _arg1(arg_int), _arg2(arg_str), _nc(nc)

{}

NodeStatus tick() override

{

std::cout << name() << ": " << _arg1 << " / " << _arg2 << " / " << _nc.value()

<< std::endl;

return NodeStatus::SUCCESS;

}

static PortsList providedPorts()

{

return {};

}

private:

int _arg1;

std::string _arg2;

NoCopyObj& _nc;

};

// Action_B implements an init(...) method that must be called once at the beginning.

class Action_B : public SyncActionNode

{

public:

Action_B(const std::string& name, const NodeConfig& config)

: SyncActionNode(name, config)

{}

// we want this method to be called ONCE and BEFORE the first tick()

void initialize(int arg_int, std::string arg_str)

{

_arg1 = (arg_int);

_arg2 = (arg_str);

}

NodeStatus tick() override

{

std::cout << name() << ": " << _arg1 << " / " << _arg2 << std::endl;

return NodeStatus::SUCCESS;

}

static PortsList providedPorts()

{

return {};

}

private:

int _arg1;

std::string _arg2;

};

// Simple tree, used to execute once each action.

static const char* xml_text = R"(

<root BTCPP_format="4">

<BehaviorTree>

<Sequence>

<Action_A/>

<Action_B/>

</Sequence>

</BehaviorTree>

</root>

)";

int main()

{

BehaviorTreeFactory factory;

NoCopyObj non_copyable(88);

// Passing the extra parameters to the constructor of Action_A

// note that if you want to pass an object by ref, instead of value

// (copy), you must use std::ref wrapper.

factory.registerNodeType<Action_A>("Action_A", 42, "hello world",

std::ref(non_copyable));

// Action_B will require initialization

factory.registerNodeType<Action_B>("Action_B");

auto tree = factory.createTreeFromText(xml_text);

auto visitor = [](TreeNode* node) {

if(auto action_B_node = dynamic_cast<Action_B*>(node))

{

action_B_node->initialize(69, "interesting_value");

}

};

// apply the visitor to all the nodes of the tree

tree.applyVisitor(visitor);

tree.tickWhileRunning();

/* Expected output:

Action_A: 42 / hello world / 88

Action_B: 69 / interesting_value

*/

return 0;

}