wpilibc/shared/include/Buttons/Trigger.h

/*----------------------------------------------------------------------------*/
/* Copyright (c) FIRST 2011-2017. All Rights Reserved.                        */
/* Open Source Software - may be modified and shared by FRC teams. The code   */
/* must be accompanied by the FIRST BSD license file in the root directory of */
/* the project.                                                               */
/*----------------------------------------------------------------------------*/

#pragma once

#include <memory>
#include <string>

#include "SmartDashboard/Sendable.h"

namespace frc {

class Command;

/**
 * This class provides an easy way to link commands to inputs.
 *
 * It is very easy to link a polled input to a command.  For instance, you could
 * link the trigger button of a joystick to a "score" command or an encoder
 * reaching
 * a particular value.
 *
 * It is encouraged that teams write a subclass of Trigger if they want to have
 * something unusual (for instance, if they want to react to the user holding
 * a button while the robot is reading a certain sensor input).  For this, they
 * only have to write the {@link Trigger#Get()} method to get the full
 * functionality
 * of the Trigger class.
 */
class Trigger : public Sendable {
 public:
  Trigger() = default;
  virtual ~Trigger() = default;
  bool Grab();
  virtual bool Get() = 0;
  void WhenActive(Command* command);
  void WhileActive(Command* command);
  void WhenInactive(Command* command);
  void CancelWhenActive(Command* command);
  void ToggleWhenActive(Command* command);

  void InitTable(std::shared_ptr<ITable> subtable) override;
  std::shared_ptr<ITable> GetTable() const override;
  std::string GetSmartDashboardType() const override;

 protected:
  std::shared_ptr<ITable> m_table;
};

}  // namespace frc