Add Subsystem factories

Author: rzblue

wpilibNewCommands/src/main/java/edu/wpi/first/wpilibj2/command/Subsystem.java

@@ -7,6 +7,8 @@
 import edu.wpi.first.util.sendable.Sendable;
 import edu.wpi.first.util.sendable.SendableBuilder;
 import edu.wpi.first.util.sendable.SendableRegistry;
+import java.util.Set;
+import java.util.function.Supplier;
 
 /**
  * A robot subsystem. Subsystems are the basic unit of robot organization in the Command-based
@@ -179,6 +181,18 @@ public Command runEnd(Runnable run, Runnable end) {
     return Commands.runEnd(run, end, this);
   }
 
+  /**
+   * Constructs a {@link DeferredCommand} with the provided supplier. This subsystem is added as a
+   * requirement.
+   *
+   * @param supplier the command supplier.
+   * @return the command.
+   * @see DeferredCommand
+   */
+  public Command defer(Supplier<Command> supplier) {
+    return Commands.defer(supplier, Set.of(this));
+  }
+
   /**
    * Associates a {@link Sendable} with this Subsystem. Also update the child's name.
    *

wpilibNewCommands/src/main/native/cpp/frc2/command/Subsystem.cpp

@@ -81,6 +81,14 @@ CommandPtr Subsystem::RunEnd(std::function<void()> run,
   return cmd::RunEnd(std::move(run), std::move(end), {this});
 }
 
+CommandPtr Subsystem::Defer(wpi::unique_function<Command*()> supplier) {
+  return cmd::Defer(std::move(supplier), {this});
+}
+
+CommandPtr Subsystem::Defer(wpi::unique_function<CommandPtr()> supplier) {
+  return cmd::Defer(std::move(supplier), {this});
+}
+
 void Subsystem::InitSendable(wpi::SendableBuilder& builder) {
   builder.SetSmartDashboardType("Subsystem");
   builder.AddBooleanProperty(

wpilibNewCommands/src/main/native/include/frc2/command/Subsystem.h

@@ -186,6 +186,24 @@ class Subsystem : public wpi::Sendable, public wpi::SendableHelper<Subsystem> {
   [[nodiscard]]
   CommandPtr RunEnd(std::function<void()> run, std::function<void()> end);
 
+  /**
+   * Constructs a DeferredCommand with the provided supplier. This subsystem is
+   * added as a requirement.
+   *
+   * @param supplier the command supplier.
+   * @return the command.
+   */
+  CommandPtr Defer(wpi::unique_function<Command*()> supplier);
+
+  /**
+   * Constructs a DeferredCommand with the provided supplier. This subsystem is
+   * added as a requirement.
+   *
+   * @param supplier the command supplier.
+   * @return the command.
+   */
+  CommandPtr Defer(wpi::unique_function<CommandPtr()> supplier);
+
   void InitSendable(wpi::SendableBuilder& builder) override;
 
  protected: