[commands] Add onlyWhile and onlyIf (#5291)

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

@@ -41,6 +41,10 @@ CommandPtr Command::Until(std::function<bool()> condition) && {
   return std::move(*this).ToPtr().Until(std::move(condition));
 }
 
+CommandPtr Command::OnlyWhile(std::function<bool()> condition) && {
+  return std::move(*this).ToPtr().OnlyWhile(std::move(condition));
+}
+
 CommandPtr Command::IgnoringDisable(bool doesRunWhenDisabled) && {
   return std::move(*this).ToPtr().IgnoringDisable(doesRunWhenDisabled);
 }
@@ -96,6 +100,10 @@ CommandPtr Command::Unless(std::function<bool()> condition) && {
   return std::move(*this).ToPtr().Unless(std::move(condition));
 }
 
+CommandPtr Command::OnlyIf(std::function<bool()> condition) && {
+  return std::move(*this).ToPtr().OnlyIf(std::move(condition));
+}
+
 CommandPtr Command::FinallyDo(std::function<void(bool)> end) && {
   return std::move(*this).ToPtr().FinallyDo(std::move(end));
 }

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

@@ -151,6 +151,11 @@ CommandPtr CommandPtr::Until(std::function<bool()> condition) && {
   return std::move(*this);
 }
 
+CommandPtr CommandPtr::OnlyWhile(std::function<bool()> condition) && {
+  AssertValid();
+  return std::move(*this).Until(std::not_fn(std::move(condition)));
+}
+
 CommandPtr CommandPtr::Unless(std::function<bool()> condition) && {
   AssertValid();
   m_ptr = std::make_unique<ConditionalCommand>(
@@ -159,6 +164,11 @@ CommandPtr CommandPtr::Unless(std::function<bool()> condition) && {
   return std::move(*this);
 }
 
+CommandPtr CommandPtr::OnlyIf(std::function<bool()> condition) && {
+  AssertValid();
+  return std::move(*this).Unless(std::not_fn(std::move(condition)));
+}
+
 CommandPtr CommandPtr::DeadlineWith(CommandPtr&& parallel) && {
   AssertValid();
   std::vector<std::unique_ptr<Command>> vec;

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

@@ -137,6 +137,17 @@ class Command {
    */
   [[nodiscard]] CommandPtr Until(std::function<bool()> condition) &&;
 
+  /**
+   * Decorates this command with a run condition.  If the specified condition
+   * becomes false before the command finishes normally, the command will be
+   * interrupted and un-scheduled. Note that this only applies to the command
+   * returned by this method; the calling command is not itself changed.
+   *
+   * @param condition the interrupt condition
+   * @return the command with the interrupt condition added
+   */
+  [[nodiscard]] CommandPtr OnlyWhile(std::function<bool()> condition) &&;
+
   /**
    * Decorates this command with an interrupt condition.  If the specified
    * condition becomes true before the command finishes normally, the command
@@ -245,6 +256,17 @@ safe) semantics.
    */
   [[nodiscard]] CommandPtr Unless(std::function<bool()> condition) &&;
 
+  /**
+   * Decorates this command to only run if this condition is met. If the command
+   * is already running and the condition changes to false, the command will not
+   * stop running. The requirements of this command will be kept for the new
+   * conditional command.
+   *
+   * @param condition the condition that will allow the command to run
+   * @return the decorated command
+   */
+  [[nodiscard]] CommandPtr OnlyIf(std::function<bool()> condition) &&;
+
   /**
    * Decorates this command to run or stop when disabled.
    *

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

@@ -159,6 +159,17 @@ class CommandPtr final {
    */
   [[nodiscard]] CommandPtr Until(std::function<bool()> condition) &&;
 
+  /**
+   * Decorates this command with a run condition.  If the specified condition
+   * becomes false before the command finishes normally, the command will be
+   * interrupted and un-scheduled. Note that this only applies to the command
+   * returned by this method; the calling command is not itself changed.
+   *
+   * @param condition the interrupt condition
+   * @return the command with the interrupt condition added
+   */
+  [[nodiscard]] CommandPtr OnlyWhile(std::function<bool()> condition) &&;
+
   /**
    * Decorates this command to only run if this condition is not met. If the
    * command is already running and the condition changes to true, the command
@@ -170,6 +181,17 @@ class CommandPtr final {
    */
   [[nodiscard]] CommandPtr Unless(std::function<bool()> condition) &&;
 
+  /**
+   * Decorates this command to only run if this condition is met. If the command
+   * is already running and the condition changes to false, the command will not
+   * stop running. The requirements of this command will be kept for the new
+   * conditional command.
+   *
+   * @param condition the condition that will allow the command to run
+   * @return the decorated command
+   */
+  [[nodiscard]] CommandPtr OnlyIf(std::function<bool()> condition) &&;
+
   /**
    * Decorates this command with a set of commands to run parallel to it, ending
    * when the calling command ends and interrupting all the others. Often more