WPILibC++ 2023.2.1-57-gb879a6f
frc2::Command Class Referenceabstract

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

#include <frc2/command/Command.h>

Inheritance diagram for frc2::Command:
frc2::CommandBase frc2::CommandHelper< CommandBase, ConditionalCommand > frc2::CommandHelper< CommandBase, FunctionalCommand > frc2::CommandHelper< CommandBase, MecanumControllerCommand > frc2::CommandHelper< CommandBase, NotifierCommand > frc2::CommandHelper< CommandBase, PIDCommand > frc2::CommandHelper< CommandBase, PerpetualCommand > frc2::CommandHelper< CommandBase, ProfiledPIDCommand< Distance > > frc2::CommandHelper< CommandBase, ProxyCommand > frc2::CommandHelper< CommandBase, ProxyScheduleCommand > frc2::CommandHelper< CommandBase, RamseteCommand > frc2::CommandHelper< CommandBase, RepeatCommand > frc2::CommandHelper< CommandBase, ScheduleCommand > frc2::CommandHelper< CommandBase, SelectCommand< Key > > frc2::CommandHelper< CommandBase, SwerveControllerCommand< NumModules > > frc2::CommandHelper< CommandBase, TrapezoidProfileCommand< Distance > > frc2::CommandHelper< CommandBase, WaitCommand > frc2::CommandHelper< CommandBase, WaitUntilCommand > frc2::CommandHelper< CommandBase, WrapperCommand > frc2::CommandGroupBase

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
 
Commandoperator= (const Command &rhs)
 
 Command (Command &&)=default
 
Commandoperator= (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< CommandTransferOwnership () &&=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

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
toRunthe Runnable to run
requirementsthe 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
toRunthe Runnable to run
requirementsthe 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
toRunthe Runnable to run
requirementsthe 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
toRunthe Runnable to run
requirementsthe 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()

◆ Execute()

◆ 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
enda 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
handlera 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
requirementthe 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
doesRunWhenDisabledtrue to run when disabled.
Returns
the decorated command

◆ Initialize()

◆ 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()

◆ 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
nameThe 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.

Implemented in frc2::CommandHelper< CommandBase, ConditionalCommand >, frc2::CommandHelper< CommandBase, FunctionalCommand >, frc2::CommandHelper< FunctionalCommand, InstantCommand >, frc2::CommandHelper< CommandBase, MecanumControllerCommand >, frc2::CommandHelper< CommandBase, NotifierCommand >, frc2::CommandHelper< CommandBase, PIDCommand >, frc2::CommandHelper< CommandGroupBase, ParallelCommandGroup >, frc2::CommandHelper< CommandGroupBase, ParallelDeadlineGroup >, frc2::CommandHelper< CommandGroupBase, ParallelRaceGroup >, frc2::CommandHelper< CommandBase, PerpetualCommand >, frc2::CommandHelper< InstantCommand, PrintCommand >, frc2::CommandHelper< CommandBase, ProfiledPIDCommand< Distance > >, frc2::CommandHelper< CommandBase, ProxyCommand >, frc2::CommandHelper< CommandBase, ProxyScheduleCommand >, frc2::CommandHelper< CommandBase, RamseteCommand >, frc2::CommandHelper< CommandBase, RepeatCommand >, frc2::CommandHelper< FunctionalCommand, RunCommand >, frc2::CommandHelper< CommandBase, ScheduleCommand >, frc2::CommandHelper< CommandBase, SelectCommand< Key > >, frc2::CommandHelper< CommandGroupBase, SequentialCommandGroup >, frc2::CommandHelper< FunctionalCommand, StartEndCommand >, frc2::CommandHelper< CommandBase, SwerveControllerCommand< NumModules > >, frc2::CommandHelper< CommandBase, TrapezoidProfileCommand< Distance > >, frc2::CommandHelper< CommandBase, WaitCommand >, frc2::CommandHelper< CommandBase, WaitUntilCommand >, and frc2::CommandHelper< CommandBase, WrapperCommand >.

◆ TransferOwnership()

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

Transfers ownership of this command to a unique pointer.

Used for decorator methods.

Implemented in frc2::CommandHelper< CommandBase, ConditionalCommand >, frc2::CommandHelper< CommandBase, FunctionalCommand >, frc2::CommandHelper< FunctionalCommand, InstantCommand >, frc2::CommandHelper< CommandBase, MecanumControllerCommand >, frc2::CommandHelper< CommandBase, NotifierCommand >, frc2::CommandHelper< CommandBase, PIDCommand >, frc2::CommandHelper< CommandGroupBase, ParallelCommandGroup >, frc2::CommandHelper< CommandGroupBase, ParallelDeadlineGroup >, frc2::CommandHelper< CommandGroupBase, ParallelRaceGroup >, frc2::CommandHelper< CommandBase, PerpetualCommand >, frc2::CommandHelper< InstantCommand, PrintCommand >, frc2::CommandHelper< CommandBase, ProfiledPIDCommand< Distance > >, frc2::CommandHelper< CommandBase, ProxyCommand >, frc2::CommandHelper< CommandBase, ProxyScheduleCommand >, frc2::CommandHelper< CommandBase, RamseteCommand >, frc2::CommandHelper< CommandBase, RepeatCommand >, frc2::CommandHelper< FunctionalCommand, RunCommand >, frc2::CommandHelper< CommandBase, ScheduleCommand >, frc2::CommandHelper< CommandBase, SelectCommand< Key > >, frc2::CommandHelper< CommandGroupBase, SequentialCommandGroup >, frc2::CommandHelper< FunctionalCommand, StartEndCommand >, frc2::CommandHelper< CommandBase, SwerveControllerCommand< NumModules > >, frc2::CommandHelper< CommandBase, TrapezoidProfileCommand< Distance > >, frc2::CommandHelper< CommandBase, WaitCommand >, frc2::CommandHelper< CommandBase, WaitUntilCommand >, frc2::CommandHelper< CommandBase, WrapperCommand >, and frc2::SelectCommand< Key >.

◆ 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
conditionthe 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
conditionthe 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
conditionthe 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
interruptBehaviortrue to run when disabled.
Returns
the decorated command

◆ WithName()

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

Decorates this Command with a name.

Parameters
namename
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
durationthe 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: