[commands] Add static Trigger factories for robot mode changes (#5902)

wpilibNewCommands/src/main/native/include/frc2/command/button/RobotModeTriggers.h

@@ -0,0 +1,50 @@
+// Copyright (c) FIRST and other WPILib contributors.
+// Open Source Software; you can modify and/or share it under the terms of
+// the WPILib BSD license file in the root directory of this project.
+
+#pragma once
+
+#include "frc2/command/button/Trigger.h"
+
+namespace frc2 {
+
+/**
+ * A class containing static Trigger factories for running callbacks when robot
+ * mode changes.
+ */
+class RobotModeTriggers {
+ public:
+  RobotModeTriggers() = delete;
+
+  /**
+   * Returns a trigger that is true when the robot is enabled in autonomous
+   * mode.
+   *
+   * @return A trigger that is true when the robot is enabled in autonomous
+   * mode.
+   */
+  static Trigger Autonomous();
+
+  /**
+   * Returns a trigger that is true when the robot is enabled in teleop mode.
+   *
+   * @return A trigger that is true when the robot is enabled in teleop mode.
+   */
+  static Trigger Teleop();
+
+  /**
+   * Returns a trigger that is true when the robot is disabled.
+   *
+   * @return A trigger that is true when the robot is disabled.
+   */
+  static Trigger Disabled();
+
+  /**
+   * Returns a trigger that is true when the robot is enabled in test mode.
+   *
+   * @return A trigger that is true when the robot is enabled in test mode.
+   */
+  static Trigger Test();
+};
+
+}  // namespace frc2

wpilibNewCommands/src/main/native/include/frc2/command/button/Trigger.h

@@ -268,6 +268,12 @@ class Trigger {
                    frc::Debouncer::DebounceType type =
                        frc::Debouncer::DebounceType::kRising);
 
+  /**
+   * Returns the current state of this trigger.
+   * @return A bool representing the current state of the trigger.
+   */
+  bool Get() const;
+
  private:
   frc::EventLoop* m_loop;
   std::function<bool()> m_condition;