expression.hpp File Reference

Detailed Description

This file defines the expression API. An expression is a logical construct such as :

(a:/b == 1) && (c:/d <= 2.)

pulse(a:/b)

!(c:/d == e:/f/g)

etc...

The basic logical operators are expression_not (!) and expression_composition (and, or, xor).

expression_atom is used for numeric comparison : <=, ==, >, etc.

expression_bool is a simple boolean value.

expression_pulse is an expression that will become true if a particular message happened since the last time it has been updated.

The expressions are organised as a tree. The expression results are passed by cascading callbacks to allow notification when an expression is listened to.

See also

expression_bool expression_atom expression_pulse expression_composition expression_not expression_generic

Go to the source code of this file.

Namespaces
namespace	ossia

Functions
bool	ossia::expressions::evaluate (const expression_base &e)
	evaluate
bool	ossia::expressions::evaluate (const expression_ptr &e)
void	ossia::expressions::update (const expression_base &e)
	update
void	ossia::expressions::update (const expression_ptr &e)
void	ossia::expressions::reset (expression_base &e)
	reset
void	ossia::expressions::reset (const expression_ptr &e)
bool	ossia::expressions::operator== (const expression_base &lhs, const expression_base &rhs)
	operator==(const expression_base& lhs, const expression_base& rhs) Compares two expressions.
bool	ossia::expressions::operator!= (const expression_base &lhs, const expression_base &rhs)
expression_callback_iterator	ossia::expressions::add_callback (expression_base &, expression_result_callback)
	add_callback Add a callback to an expression.
void	ossia::expressions::remove_callback (expression_base &, expression_callback_iterator)
	remove_callback Remove a callback to an expression.
std::size_t	ossia::expressions::callback_count (expression_base &)
	callback_count
const expression_base &	ossia::expressions::expression_true ()
	expression_true Convenience constant expression always evaluating to true.
const expression_base &	ossia::expressions::expression_false ()
	false Convenience constant expression always evaluating to false.
expression_ptr	ossia::expressions::make_expression_true ()
	make_expression_true
bool	ossia::expressions::is_expression_true (ossia::expression &e) noexcept
expression_ptr	ossia::expressions::make_expression_false ()
	make_expression_false
template<typename... Args>
expression_ptr	ossia::expressions::make_expression_atom (Args &&... args)
	make_expression_atom
expression_ptr	ossia::expressions::make_expression_atom (const expression_atom::val_t &lhs, comparator c, const expression_atom::val_t &rhs)
expression_ptr	ossia::expressions::make_expression_atom (expression_atom::val_t &&lhs, comparator c, expression_atom::val_t &&rhs)
template<typename... Args>
expression_ptr	ossia::expressions::make_expression_bool (Args &&... args)
	make_expression_bool
template<typename... Args>
expression_ptr	ossia::expressions::make_expression_composition (Args &&... args)
	make_expression_composition
template<typename... Args>
expression_ptr	ossia::expressions::make_expression_not (Args &&... args)
	make_expression_not
template<typename... Args>
expression_ptr	ossia::expressions::make_expression_pulse (Args &&... args)
	make_expression_pulse
template<typename T , typename... Args>
expression_ptr	ossia::expressions::make_expression_generic (Args &&... args)

Function Documentation

evaluate()

OSSIA_EXPORT bool ossia::expressions::evaluate

(

const expression_base &

e

)

evaluate

Parameters

e	An expression

Returns

The truth value of the expression

update()

OSSIA_EXPORT void ossia::expressions::update

(

const expression_base &

e

)

update

Parameters

e	An expression

Recursively asks an expression to query the addresses that it refers, in order to check if the value has changed.

reset()

OSSIA_EXPORT void ossia::expressions::reset

(

expression_base &

e

)

reset

Parameters

e	An expression

operator==()

OSSIA_EXPORT bool ossia::expressions::operator==	(	const expression_base &	lhs,
		const expression_base &	rhs
	)

operator==(const expression_base& lhs, const expression_base& rhs) Compares two expressions.

Two expressions are comparable if they have all the same terms.

callback_count()

OSSIA_EXPORT std::size_t ossia::expressions::callback_count

(

expression_base &

)

callback_count

Returns

Number of callbacks in an expression.

make_expression_true()

expression_ptr ossia::expressions::make_expression_true ( )

inline

make_expression_true

The following functions are factories used to create expressions.

Returns

A "true" expression_bool.

See also

expression_bool

make_expression_false()

expression_ptr ossia::expressions::make_expression_false ( )

inline

make_expression_false

Returns

A "false" expression_bool.

See also

expression_bool

make_expression_atom()

template<typename... Args>

expression_ptr ossia::expressions::make_expression_atom

(

Args &&...

args

)

make_expression_atom

Returns

An expression_atom

See also

expression_atom

make_expression_bool()

template<typename... Args>

expression_ptr ossia::expressions::make_expression_bool

(

Args &&...

args

)

make_expression_bool

Returns

An expression_bool

See also

expression_bool

make_expression_composition()

template<typename... Args>

expression_ptr ossia::expressions::make_expression_composition

(

Args &&...

args

)

make_expression_composition

Returns

An expression_composition

See also

expression_composition

make_expression_not()

template<typename... Args>

expression_ptr ossia::expressions::make_expression_not

(

Args &&...

args

)

make_expression_not

Returns

An expression_not

See also

expression_not

make_expression_pulse()

template<typename... Args>

expression_ptr ossia::expressions::make_expression_pulse

(

Args &&...

args

)

make_expression_pulse

Returns

An expression_pulse

See also

expression_pulse