A source value. Reading it with get() inside a tracked run subscribes that run. More...

#include <signal.hpp>

Inheritance diagram for morph::reactive::Signal< T >:

Public Member Functions
	Signal (Runtime &runtime)
	Constructs a value-initialised signal.
	Signal (Runtime &runtime, T initial, EqualityPolicy policy=EqualityPolicy::Auto)
	Constructs a signal holding `initial`.
	Signal (Signal const &)=delete
Signal &	operator= (Signal const &)=delete
	Signal (Signal &&)=delete
Signal &	operator= (Signal &&)=delete
T const &	get () const
	Reads the value, subscribing the innermost tracked run.
T const &	peek () const noexcept
	Reads the value without subscribing anything.
void	set (T value)
	Replaces the value and notifies observers, unless it equals the current one and the policy is EqualityPolicy::Auto.
template<typename F> requires std::invocable<F, T&>
void	mutate (F &&fn)
	Changes the value in place and always notifies observers.
Public Member Functions inherited from morph::reactive::detail::Node
	Node (std::shared_ptr< RuntimeCore > core, std::size_t depth=0)
	Constructs a node. Off the owner this is reported (site::kOffOwner) and the node is not counted towards the core's live nodes, whose counter belongs to the owner.
virtual	~Node ()
	Unlinks this node from its sources and observers, drops every reference the core holds to it, and tells a pull running on it that it is gone.
	Node (Node const &)=delete
Node &	operator= (Node const &)=delete
	Node (Node &&)=delete
Node &	operator= (Node &&)=delete
void	markStale (Colour colour)
	Push phase: raises this node to `colour` and marks its observers Check.
bool	updateIfNecessary ()
	Pull phase: brings this node up to date, recomputing only if a source really changed.
std::size_t	countRun (std::uint64_t epoch) noexcept
	Counts one run of this Effect in the flush numbered `epoch`.
std::size_t	depth () const noexcept
	How deeply the scope owning this node is nested; the flush runs shallower Effects first.
bool	runsAfter (Node const &other) const noexcept
	Whether this node runs after `other` when both are queued: it is deeper, or as deep and newer.
std::uint64_t	creationOrder () const noexcept
	Where this node stands in its runtime's creation order; among Effects of one depth, the flush runs older ones first.
void	settle () noexcept
	Marks this node Clean without running it (a dropped queue entry).

Additional Inherited Members
Protected Member Functions inherited from morph::reactive::detail::Node
RuntimeCore &	core () const noexcept
	The runtime core.
bool	bornOnOwner () const noexcept
	Whether this node was constructed on the owner; one that was not is refused its work.
void	trackRead () const
	Registers this node as a source of the innermost tracked run, if any.
void	forceDirty () noexcept
	Marks this node Dirty, so the next pull recomputes it.
bool	isPulling () const noexcept
	Whether a pull is bringing this node up to date right now. A read of the node from inside that pull can only come from its own run or from a source's run that reads it: a cycle.
void	markObserversStale (Colour colour)
	Marks every observer of this node `colour`.
void	adoptSources (std::vector< Node * > fresh)
	Replaces this node's sources with `fresh`, unlinking the ones no longer read.
void	mergeSources (std::vector< Node * > fresh)
	Adds `fresh` to this node's sources without dropping any: what a failed run keeps.

Detailed Description

template<typename T>
class morph::reactive::Signal< T >

A source value. Reading it with get() inside a tracked run subscribes that run.

set() skips a value equal to the current one when == is usable for T (kEqualityUsable) and the policy is EqualityPolicy::Auto; mutate() always notifies. Writes are refused, and reported, off the owner or inside a Computed. A read off the owner is reported and subscribes nothing.

Template Parameters

T	The value type; move-constructible and move-assignable.

Definition at line 49 of file signal.hpp.

Constructor & Destructor Documentation

◆ Signal() [1/2]

template<typename T>

morph::reactive::Signal< T >::Signal ( Runtime & runtime )

inlineexplicit

Constructs a value-initialised signal.

Parameters

runtime The runtime this signal belongs to.

Definition at line 53 of file signal.hpp.

◆ Signal() [2/2]

template<typename T>

morph::reactive::Signal< T >::Signal	(	Runtime &	runtime,
		T	initial,
		EqualityPolicy	policy = EqualityPolicy::Auto )

inline

Constructs a signal holding initial.

Parameters

runtime	The runtime this signal belongs to.
initial	The initial value.
policy	Whether a write equal to the current value is skipped.

Definition at line 61 of file signal.hpp.

Member Function Documentation

◆ get()

template<typename T>

T const & morph::reactive::Signal< T >::get ( ) const

inlinenodiscard

Reads the value, subscribing the innermost tracked run.

Off the owner the read is reported (detail::site::kOffOwner) and proceeds untracked: it subscribes nothing and leaves the tracking state alone. The value it returns is then read without synchronisation against the owner's writes.

Returns: The current value; valid until the next write.

Definition at line 76 of file signal.hpp.

◆ peek()

template<typename T>

T const & morph::reactive::Signal< T >::peek ( ) const

inlinenodiscardnoexcept

Reads the value without subscribing anything.

Returns: The current value; valid until the next write.

Definition at line 85 of file signal.hpp.

◆ set()

template<typename T>

void morph::reactive::Signal< T >::set ( T value )

inline

Replaces the value and notifies observers, unless it equals the current one and the policy is EqualityPolicy::Auto.

Parameters

value The new value.

Definition at line 90 of file signal.hpp.

◆ mutate()

template<typename T>

template<typename F>
requires std::invocable<F, T&>

void morph::reactive::Signal< T >::mutate ( F && fn )

inline

Changes the value in place and always notifies observers.

Template Parameters

F	A callable taking T&.

Parameters

fn	The mutation.

Definition at line 108 of file signal.hpp.

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

morph/reactive/signal.hpp

Public Member Functions

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ Signal() [1/2]

◆ Signal() [2/2]

Member Function Documentation

◆ get()

◆ peek()

◆ set()

◆ mutate()