observable::expr::expression< ValueType, EvaluatorType > Class Template Reference

Description

template<typename ValueType, typename EvaluatorType = expression_evaluator>
class observable::expr::expression< ValueType, EvaluatorType >

Expressions manage expression tree evaluation and results.

Expressions are also value updaters, so they can be used for updating a value when an expression tree changes.

Template Parameters

ValueType	The expression's result value type. This is what get() returns.
EvaluatorType	An instance of expression_evaluator, or a type derived from it.

Warning

None of the methods in this class can be safely called concurrently.

Public Member Functions
	expression (expression_node< ValueType > &&root, EvaluatorType const &evaluator)
	Create a new expression from the root node of an expression tree. More...
void	eval ()
	Evaluate the expression. More...
virtual auto	get () const -> ValueType override
	Retrieve the expression's result. More...
virtual void	set_value_notifier (std::function< void(ValueType &&)> const &notifier) override
	Set a functor that can be used to notify the value to be updated of a change. More...
virtual	~expression ()
	Destructor. More...
	expression ()=default
	Expressions are default-constructible. More...
	expression (expression const &)=delete
	Expressions are not copy-constructible. More...
auto	operator= (expression const &) -> expression &=delete
	Expressions are not copy-assignable. More...
	expression (expression &&)=default
	Expressions are move-constructible. More...
auto	operator= (expression &&) -> expression &=default
	Expressions are move-assignable. More...
Public Member Functions inherited from observable::value_updater< ValueType >
virtual	~value_updater ()
	Destructor. More...
	value_updater ()=default
	Value updaters are default-constructible. More...
	value_updater (value_updater const &)=default
	Value updaters are copy-constructible. More...
	value_updater (value_updater &&)=default
	Value updaters are move-constructible. More...
value_updater &	operator= (value_updater const &)=default
	Value updaters are copy-assignable. More...
value_updater &	operator= (value_updater &&)=default
	Value updaters are move-assignable. More...

Protected Member Functions
auto	root_node () -> expression_node< ValueType > &
	Return the expression tree's root node. More...

Constructor & Destructor Documentation

expression() [1/4]

template<typename ValueType, typename EvaluatorType = expression_evaluator>

observable::expr::expression< ValueType, EvaluatorType >::expression ( expression_node< ValueType > &&  root, EvaluatorType const &  evaluator  )

inline

Create a new expression from the root node of an expression tree.

Parameters

[in]	root	Expression tree root node.
[in]	evaluator	Expression evaluator to be used for globally updating the expression.

~expression()

template<typename ValueType, typename EvaluatorType = expression_evaluator>

virtual observable::expr::expression< ValueType, EvaluatorType >::~expression ( )

inlinevirtual

Destructor.

expression() [2/4]

template<typename ValueType, typename EvaluatorType = expression_evaluator>

observable::expr::expression< ValueType, EvaluatorType >::expression ( )

default

Expressions are default-constructible.

expression() [3/4]

template<typename ValueType, typename EvaluatorType = expression_evaluator>

observable::expr::expression< ValueType, EvaluatorType >::expression ( expression< ValueType, EvaluatorType > const &  )

delete

Expressions are not copy-constructible.

expression() [4/4]

template<typename ValueType, typename EvaluatorType = expression_evaluator>

observable::expr::expression< ValueType, EvaluatorType >::expression ( expression< ValueType, EvaluatorType > &&  )

default

Expressions are move-constructible.

Member Function Documentation

eval()

template<typename ValueType, typename EvaluatorType = expression_evaluator>

void observable::expr::expression< ValueType, EvaluatorType >::eval ( )

inline

Evaluate the expression.

This will ensure that the expression's result is up-to-date.

get()

template<typename ValueType, typename EvaluatorType = expression_evaluator>

virtual auto observable::expr::expression< ValueType, EvaluatorType >::get ( ) const -> ValueType

inlineoverridevirtual

Retrieve the expression's result.

Warning

If eval() has not been called, the result might be stale.

Implements observable::value_updater< ValueType >.

set_value_notifier()

template<typename ValueType, typename EvaluatorType = expression_evaluator>

virtual void observable::expr::expression< ValueType, EvaluatorType >::set_value_notifier ( std::function< void(ValueType &&)> const &  notifier )

inlineoverridevirtual

Set a functor that can be used to notify the value to be updated of a change.

Parameters

[in]

notifier

Functor that will notify the value of a change.

Implements observable::value_updater< ValueType >.

operator=() [1/2]

template<typename ValueType, typename EvaluatorType = expression_evaluator>

auto observable::expr::expression< ValueType, EvaluatorType >::operator= ( expression< ValueType, EvaluatorType > const &  ) -> expression &=delete

delete

Expressions are not copy-assignable.

operator=() [2/2]

template<typename ValueType, typename EvaluatorType = expression_evaluator>

auto observable::expr::expression< ValueType, EvaluatorType >::operator= ( expression< ValueType, EvaluatorType > &&  ) -> expression &=default

default

Expressions are move-assignable.

root_node()

template<typename ValueType, typename EvaluatorType = expression_evaluator>

auto observable::expr::expression< ValueType, EvaluatorType >::root_node ( ) -> expression_node<ValueType> &

inlineprotected

Return the expression tree's root node.