text: /**
   * @file expressions.h
   * @brief customize expression functions
   * @date Nov 8, 2016
   * @author Jing Dong
   */
  
  #pragma once
  
  // functions to build expressions
  #include "functions.h"
  
  // type expression definitions
  #include <gtsam/nonlinear/expressions.h>
  #include <gtsam/slam/expressions.h>
  
  
  namespace gtsamexamples {
  
  // expression project Pose2 to Point2
  inline gtsam::Point2_ projectPose2_(const gtsam::Pose2_& pose) {
    return gtsam::Point2_(&projectPose2, pose);
  }
  
  } // namespace gtsamexamples
  
  