fix compilation

Author: facontidavide

include/behaviortree_cpp_v3/decorators/blackboard_precondition.h

@@ -62,6 +62,17 @@ class BlackboardPreconditionNode : public DecoratorNode
 
 //----------------------------------------------------
 
+template<typename T> inline bool IsSame(const T& a, const T& b)
+{
+  return a == b;
+}
+
+inline bool IsSame(const double& a, const double& b)
+{
+  constexpr double EPS = static_cast<double>(std::numeric_limits<float>::epsilon());
+  return std::abs(a - b) <= EPS;
+}
+
 template<typename T> inline
 NodeStatus BlackboardPreconditionNode<T>::tick()
 {
@@ -72,17 +83,10 @@ NodeStatus BlackboardPreconditionNode<T>::tick()
     setStatus(NodeStatus::RUNNING);
 
     if( getInput("value_A", value_A) &&
-        getInput("value_B", value_B) )
+        getInput("value_B", value_B) &&
+        IsSame(value_A, value_B))
     {
-        bool is_equal = (value_B == value_A);
-        if ( std::is_same<double, T>::value || std::is_same<float, T>::value )
-        {
-            is_equal = std::abs(value_B - value_A) <= std::numeric_limits<float>::epsilon();
-        }
-        if(is_equal)
-        {
-            return child_node_->executeTick();
-        }
+        return child_node_->executeTick();
     }
 
     if( child()->status() == NodeStatus::RUNNING )
@@ -93,6 +97,7 @@ NodeStatus BlackboardPreconditionNode<T>::tick()
     return default_return_status;
 }
 
+
 } // end namespace
 
 #endif