A state machine representing a complete action to be performed by the robot. More...

#include <frc2/command/Command.h>

Inheritance diagram for frc2::Command:

Public Types
enum class	InterruptionBehavior { kCancelSelf , kCancelIncoming }
	An enum describing the command's behavior when another command with a shared requirement is scheduled. More...

Public Member Functions
	Command ()=default

virtual	~Command ()

	Command (const Command &)=default

Command &	operator= (const Command &rhs)

	Command (Command &&)=default

Command &	operator= (Command &&)=default

virtual void	Initialize ()
	The initial subroutine of a command. More...

virtual void	Execute ()
	The main body of a command. More...

virtual void	End (bool interrupted)
	The action to take when the command ends. More...

virtual bool	IsFinished ()
	Whether the command has finished. More...

virtual wpi::SmallSet< Subsystem *, 4 >	GetRequirements () const =0
	Specifies the set of subsystems used by this command. More...

CommandPtr	WithTimeout (units::second_t duration) &&
	Decorates this command with a timeout. More...

CommandPtr	Until (std::function< bool()> condition) &&
	Decorates this command with an interrupt condition. More...

CommandPtr	WithInterrupt (std::function< bool()> condition) &&
	Decorates this command with an interrupt condition. More...

CommandPtr	BeforeStarting (std::function< void()> toRun, std::initializer_list< Subsystem * > requirements) &&
	Decorates this command with a runnable to run before this command starts. More...

CommandPtr	BeforeStarting (std::function< void()> toRun, std::span< Subsystem *const > requirements={}) &&
	Decorates this command with a runnable to run before this command starts. More...

CommandPtr	AndThen (std::function< void()> toRun, std::initializer_list< Subsystem * > requirements) &&
	Decorates this command with a runnable to run after the command finishes. More...

CommandPtr	AndThen (std::function< void()> toRun, std::span< Subsystem *const > requirements={}) &&
	Decorates this command with a runnable to run after the command finishes. More...

PerpetualCommand	Perpetually () &&

CommandPtr	Repeatedly () &&
	Decorates this command to run repeatedly, restarting it when it ends, until this command is interrupted. More...

CommandPtr	AsProxy () &&
	Decorates this command to run "by proxy" by wrapping it in a ProxyCommand. More...

CommandPtr	Unless (std::function< bool()> condition) &&
	Decorates this command to only run if this condition is not met. More...

CommandPtr	IgnoringDisable (bool doesRunWhenDisabled) &&
	Decorates this command to run or stop when disabled. More...

CommandPtr	WithInterruptBehavior (Command::InterruptionBehavior interruptBehavior) &&
	Decorates this command to run or stop when disabled. More...

CommandPtr	FinallyDo (std::function< void(bool)> end) &&
	Decorates this command with a lambda to call on interrupt or end, following the command's inherent Command::End(bool) method. More...

CommandPtr	HandleInterrupt (std::function< void()> handler) &&
	Decorates this command with a lambda to call on interrupt, following the command's inherent Command::End(bool) method. More...

CommandPtr	WithName (std::string_view name) &&
	Decorates this Command with a name. More...

void	Schedule ()
	Schedules this command. More...

void	Cancel ()
	Cancels this command. More...

bool	IsScheduled () const
	Whether or not the command is currently scheduled. More...

bool	HasRequirement (Subsystem *requirement) const
	Whether the command requires a given subsystem. More...

bool	IsComposed () const
	Whether the command is currently grouped in a command group. More...

void	SetComposed (bool isComposed)
	Sets whether the command is currently composed in a command composition. More...

bool	IsGrouped () const
	Whether the command is currently grouped in a command group. More...

void	SetGrouped (bool grouped)
	Sets whether the command is currently grouped in a command group. More...

virtual bool	RunsWhenDisabled () const
	Whether the given command should run when the robot is disabled. More...

virtual InterruptionBehavior	GetInterruptionBehavior () const
	How the command behaves when another command with a shared requirement is scheduled. More...

virtual std::string	GetName () const
	Gets the name of this Command. More...

virtual void	SetName (std::string_view name)
	Sets the name of this Command. More...

virtual CommandPtr	ToPtr () &&=0
	Transfers ownership of this command to a unique pointer. More...

Protected Member Functions
virtual std::unique_ptr< Command >	TransferOwnership () &&=0
	Transfers ownership of this command to a unique pointer. More...

Protected Attributes
bool	m_isComposed = false

Friends
class	CommandPtr

Detailed Description

A state machine representing a complete action to be performed by the robot.

Commands are run by the CommandScheduler, and can be composed into CommandGroups to allow users to build complicated multi-step actions without the need to roll the state machine logic themselves.

Commands are run synchronously from the main robot loop; no multithreading is used, unless specified explicitly from the command implementation.

Note: ALWAYS create a subclass by extending CommandHelper<Base, Subclass>, or decorators will not function!

This class is provided by the NewCommands VendorDep

See also: CommandScheduler; CommandHelper

Member Enumeration Documentation

◆ InterruptionBehavior

enum class frc2::Command::InterruptionBehavior

strong

An enum describing the command's behavior when another command with a shared requirement is scheduled.

Enumerator

kCancelSelf

This command ends, End(true) is called, and the incoming command is scheduled normally.

This is the default behavior.

kCancelIncoming

This command continues, and the incoming command is not scheduled.

Constructor & Destructor Documentation

◆ Command() [1/3]

frc2::Command::Command ( )

default

◆ ~Command()

virtual frc2::Command::~Command ( )

virtual

◆ Command() [2/3]

frc2::Command::Command ( const Command & )

default

◆ Command() [3/3]

frc2::Command::Command ( Command && )

default

Member Function Documentation

◆ AndThen() [1/2]

CommandPtr frc2::Command::AndThen	(	std::function< void()>	toRun,
		std::initializer_list< Subsystem * >	requirements
	)		&&

Decorates this command with a runnable to run after the command finishes.

Parameters

toRun	the Runnable to run
requirements	the required subsystems

Returns: the decorated command

◆ AndThen() [2/2]

CommandPtr frc2::Command::AndThen	(	std::function< void()>	toRun,
		std::span< Subsystem *const >	requirements = `{}`
	)		&&

Decorates this command with a runnable to run after the command finishes.

Parameters

toRun	the Runnable to run
requirements	the required subsystems

Returns: the decorated command

◆ AsProxy()

CommandPtr frc2::Command::AsProxy ( ) &&

Decorates this command to run "by proxy" by wrapping it in a ProxyCommand.

This is useful for "forking off" from command groups when the user does not wish to extend the command's requirements to the entire command group.

This overload transfers command ownership to the returned CommandPtr.

Returns: the decorated command

◆ BeforeStarting() [1/2]

CommandPtr frc2::Command::BeforeStarting	(	std::function< void()>	toRun,
		std::initializer_list< Subsystem * >	requirements
	)		&&

Decorates this command with a runnable to run before this command starts.

Parameters

toRun	the Runnable to run
requirements	the required subsystems

Returns: the decorated command

◆ BeforeStarting() [2/2]

CommandPtr frc2::Command::BeforeStarting	(	std::function< void()>	toRun,
		std::span< Subsystem *const >	requirements = `{}`
	)		&&

Decorates this command with a runnable to run before this command starts.

Parameters

toRun	the Runnable to run
requirements	the required subsystems

Returns: the decorated command

◆ Cancel()

void frc2::Command::Cancel ( )

Cancels this command.

Will call End(true). Commands will be canceled regardless of interruption behavior.

◆ End()

virtual void frc2::Command::End ( bool interrupted )

virtual

The action to take when the command ends.

Called when either the command finishes normally, or when it interrupted/canceled.

Parameters

interrupted whether the command was interrupted/canceled

Reimplemented in frc2::ParallelCommandGroup, frc2::ParallelDeadlineGroup, frc2::ParallelRaceGroup, frc2::SequentialCommandGroup, frc2::ConditionalCommand, frc2::FunctionalCommand, frc2::MecanumControllerCommand, frc2::NotifierCommand, frc2::PerpetualCommand, frc2::PIDCommand, frc2::ProfiledPIDCommand< Distance >, frc2::ProxyCommand, frc2::ProxyScheduleCommand, frc2::RamseteCommand, frc2::RepeatCommand, frc2::SelectCommand< Key >, frc2::SwerveControllerCommand< NumModules >, frc2::TrapezoidProfileCommand< Distance >, frc2::WaitCommand, and frc2::WrapperCommand.

◆ Execute()

virtual void frc2::Command::Execute ( )

virtual

The main body of a command.

Called repeatedly while the command is scheduled.

Reimplemented in frc2::ParallelCommandGroup, frc2::ParallelDeadlineGroup, frc2::ParallelRaceGroup, frc2::SequentialCommandGroup, frc2::ConditionalCommand, frc2::FunctionalCommand, frc2::MecanumControllerCommand, frc2::PerpetualCommand, frc2::PIDCommand, frc2::ProfiledPIDCommand< Distance >, frc2::ProxyCommand, frc2::ProxyScheduleCommand, frc2::RamseteCommand, frc2::RepeatCommand, frc2::SelectCommand< Key >, frc2::SwerveControllerCommand< NumModules >, frc2::TrapezoidProfileCommand< Distance >, and frc2::WrapperCommand.

◆ FinallyDo()

CommandPtr frc2::Command::FinallyDo ( std::function< void(bool)> end ) &&

Decorates this command with a lambda to call on interrupt or end, following the command's inherent Command::End(bool) method.

Parameters

end	a lambda accepting a boolean parameter specifying whether the command was interrupted.

Returns: the decorated command

◆ GetInterruptionBehavior()

virtual InterruptionBehavior frc2::Command::GetInterruptionBehavior ( ) const

inlinevirtual

How the command behaves when another command with a shared requirement is scheduled.

Returns: a variant of InterruptionBehavior, defaulting to kCancelSelf.

Reimplemented in frc2::ParallelCommandGroup, frc2::ParallelDeadlineGroup, frc2::ParallelRaceGroup, frc2::RepeatCommand, frc2::SelectCommand< Key >, frc2::SequentialCommandGroup, and frc2::WrapperCommand.

◆ GetName()

virtual std::string frc2::Command::GetName ( ) const

virtual

Gets the name of this Command.

Defaults to the simple class name if not overridden.

Returns: The display name of the Command

Reimplemented in frc2::CommandBase.

◆ GetRequirements()

virtual wpi::SmallSet< Subsystem *, 4 > frc2::Command::GetRequirements ( ) const

pure virtual

Specifies the set of subsystems used by this command.

Two commands cannot use the same subsystem at the same time. If another command is scheduled that shares a requirement, GetInterruptionBehavior() will be checked and followed. If no subsystems are required, return an empty set.

Note: it is recommended that user implementations contain the requirements as a field, and return that field here, rather than allocating a new set every time this is called.

Returns: the set of subsystems that are required

See also: InterruptionBehavior

Implemented in frc2::CommandBase, and frc2::WrapperCommand.

◆ HandleInterrupt()

CommandPtr frc2::Command::HandleInterrupt ( std::function< void()> handler ) &&

Decorates this command with a lambda to call on interrupt, following the command's inherent Command::End(bool) method.

Parameters

handler a lambda to run when the command is interrupted

Returns: the decorated command

◆ HasRequirement()

bool frc2::Command::HasRequirement ( Subsystem * requirement ) const

Whether the command requires a given subsystem.

Named "HasRequirement" rather than "requires" to avoid confusion with Command::Requires(Subsystem) – this may be able to be changed in a few years.

Parameters

requirement the subsystem to inquire about

Returns: whether the subsystem is required

◆ IgnoringDisable()

CommandPtr frc2::Command::IgnoringDisable ( bool doesRunWhenDisabled ) &&

Decorates this command to run or stop when disabled.

Parameters

doesRunWhenDisabled true to run when disabled.

Returns: the decorated command

◆ Initialize()

virtual void frc2::Command::Initialize ( )

virtual

The initial subroutine of a command.

Called once when the command is initially scheduled.

Reimplemented in frc2::ParallelCommandGroup, frc2::ParallelDeadlineGroup, frc2::ParallelRaceGroup, frc2::SequentialCommandGroup, frc2::ConditionalCommand, frc2::FunctionalCommand, frc2::MecanumControllerCommand, frc2::NotifierCommand, frc2::PerpetualCommand, frc2::PIDCommand, frc2::ProfiledPIDCommand< Distance >, frc2::ProxyCommand, frc2::ProxyScheduleCommand, frc2::RamseteCommand, frc2::RepeatCommand, frc2::ScheduleCommand, frc2::SelectCommand< Key >, frc2::SwerveControllerCommand< NumModules >, frc2::TrapezoidProfileCommand< Distance >, frc2::WaitCommand, and frc2::WrapperCommand.

◆ IsComposed()

bool frc2::Command::IsComposed ( ) const

Whether the command is currently grouped in a command group.

Used as extra insurance to prevent accidental independent use of grouped commands.

◆ IsFinished()

virtual bool frc2::Command::IsFinished ( )

inlinevirtual

Whether the command has finished.

Once a command finishes, the scheduler will call its end() method and un-schedule it.

Returns: whether the command has finished.

Reimplemented in frc2::ParallelCommandGroup, frc2::ParallelDeadlineGroup, frc2::ParallelRaceGroup, frc2::SequentialCommandGroup, frc2::ConditionalCommand, frc2::FunctionalCommand, frc2::MecanumControllerCommand, frc2::ProxyCommand, frc2::ProxyScheduleCommand, frc2::RamseteCommand, frc2::RepeatCommand, frc2::ScheduleCommand, frc2::SelectCommand< Key >, frc2::SwerveControllerCommand< NumModules >, frc2::TrapezoidProfileCommand< Distance >, frc2::WaitCommand, frc2::WaitUntilCommand, and frc2::WrapperCommand.

◆ IsGrouped()

bool frc2::Command::IsGrouped ( ) const

Whether the command is currently grouped in a command group.

Used as extra insurance to prevent accidental independent use of grouped commands.

Deprecated:: Moved to IsComposed()

◆ IsScheduled()

bool frc2::Command::IsScheduled ( ) const

Whether or not the command is currently scheduled.

Note that this does not detect whether the command is in a composition, only whether it is directly being run by the scheduler.

Returns: Whether the command is scheduled.

◆ operator=() [1/2]

Command & frc2::Command::operator= ( Command && )

default

◆ operator=() [2/2]

Command & frc2::Command::operator= ( const Command & rhs )

◆ Perpetually()

PerpetualCommand frc2::Command::Perpetually ( ) &&

 Decorates this command to run perpetually, ignoring its ordinary end
 conditions.  The decorated command can still be interrupted or canceled.

 @return the decorated command
 @deprecated PerpetualCommand violates the assumption that execute() doesn't

get called after isFinished() returns true – an assumption that should be valid. This was unsafe/undefined behavior from the start, and RepeatCommand provides an easy way to achieve similar end results with slightly different (and safe) semantics.

◆ Repeatedly()

CommandPtr frc2::Command::Repeatedly ( ) &&

Decorates this command to run repeatedly, restarting it when it ends, until this command is interrupted.

The decorated command can still be canceled.

Returns: the decorated command

◆ RunsWhenDisabled()

virtual bool frc2::Command::RunsWhenDisabled ( ) const

inlinevirtual

Whether the given command should run when the robot is disabled.

Override to return true if the command should run when disabled.

Returns: whether the command should run when the robot is disabled

Reimplemented in frc2::ConditionalCommand, frc2::ParallelCommandGroup, frc2::ParallelDeadlineGroup, frc2::ParallelRaceGroup, frc2::PrintCommand, frc2::RepeatCommand, frc2::ScheduleCommand, frc2::SelectCommand< Key >, frc2::SequentialCommandGroup, frc2::WaitCommand, frc2::WaitUntilCommand, and frc2::WrapperCommand.

◆ Schedule()

void frc2::Command::Schedule ( )

Schedules this command.

◆ SetComposed()

void frc2::Command::SetComposed ( bool isComposed )

Sets whether the command is currently composed in a command composition.

Can be used to "reclaim" a command if a composition is no longer going to use it. NOT ADVISED!

◆ SetGrouped()

void frc2::Command::SetGrouped ( bool grouped )

Sets whether the command is currently grouped in a command group.

Can be used to "reclaim" a command if a group is no longer going to use it. NOT ADVISED!

Deprecated:: Moved to SetComposed()

◆ SetName()

virtual void frc2::Command::SetName ( std::string_view name )

virtual

Sets the name of this Command.

Nullop if not overridden.

Parameters

name	The display name of the Command.

Reimplemented in frc2::CommandBase.

◆ ToPtr()

virtual CommandPtr frc2::Command::ToPtr ( ) &&

pure virtual

Transfers ownership of this command to a unique pointer.

Used for decorator methods.

◆ TransferOwnership()

virtual std::unique_ptr< Command > frc2::Command::TransferOwnership ( ) &&

protectedpure virtual

Transfers ownership of this command to a unique pointer.

Used for decorator methods.

◆ Unless()

CommandPtr frc2::Command::Unless ( 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 will not stop running. The requirements of this command will be kept for the new conditional command.

Parameters

condition the condition that will prevent the command from running

Returns: the decorated command

◆ Until()

CommandPtr frc2::Command::Until ( std::function< bool()> condition ) &&

Decorates this command with an interrupt condition.

If the specified condition becomes true 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.

Parameters

condition the interrupt condition

Returns: the command with the interrupt condition added

◆ WithInterrupt()

CommandPtr frc2::Command::WithInterrupt ( std::function< bool()> condition ) &&

Decorates this command with an interrupt condition.

If the specified condition becomes true 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.

Parameters

condition the interrupt condition

Returns: the command with the interrupt condition added

Deprecated:: Replace with Until()

◆ WithInterruptBehavior()

CommandPtr frc2::Command::WithInterruptBehavior ( Command::InterruptionBehavior interruptBehavior ) &&

Decorates this command to run or stop when disabled.

Parameters

interruptBehavior true to run when disabled.

Returns: the decorated command

◆ WithName()

CommandPtr frc2::Command::WithName ( std::string_view name ) &&

Decorates this Command with a name.

Parameters

name name

Returns: the decorated Command

◆ WithTimeout()

CommandPtr frc2::Command::WithTimeout ( units::second_t duration ) &&

Decorates this command with a timeout.

If the specified timeout is exceeded before the command finishes normally, the command will be interrupted and un-scheduled. Note that the timeout only applies to the command returned by this method; the calling command is not itself changed.

Parameters

duration the timeout duration

Returns: the command with the timeout added

Friends And Related Function Documentation

◆ CommandPtr

friend class CommandPtr

friend

Member Data Documentation

◆ m_isComposed

bool frc2::Command::m_isComposed = false

protected

The documentation for this class was generated from the following file:

frc2/command/Command.h

Public Types

Public Member Functions

Protected Member Functions

Protected Attributes

Friends

Detailed Description

Member Enumeration Documentation

◆ InterruptionBehavior

Constructor & Destructor Documentation

◆ Command() [1/3]

◆ ~Command()

◆ Command() [2/3]

◆ Command() [3/3]

Member Function Documentation

◆ AndThen() [1/2]

◆ AndThen() [2/2]

◆ AsProxy()

◆ BeforeStarting() [1/2]

◆ BeforeStarting() [2/2]

◆ Cancel()

◆ End()

◆ Execute()

◆ FinallyDo()

◆ GetInterruptionBehavior()

◆ GetName()

◆ GetRequirements()

◆ HandleInterrupt()

◆ HasRequirement()

◆ IgnoringDisable()

◆ Initialize()

◆ IsComposed()

◆ IsFinished()

◆ IsGrouped()

◆ IsScheduled()

◆ operator=() [1/2]

◆ operator=() [2/2]

◆ Perpetually()

◆ Repeatedly()

◆ RunsWhenDisabled()

◆ Schedule()

◆ SetComposed()

◆ SetGrouped()

◆ SetName()

◆ ToPtr()

◆ TransferOwnership()

◆ Unless()

◆ Until()

◆ WithInterrupt()

◆ WithInterruptBehavior()

◆ WithName()

◆ WithTimeout()

Friends And Related Function Documentation

◆ CommandPtr

Member Data Documentation

◆ m_isComposed