[ceph.git] / ceph / src / boost / libs / phoenix / doc / actors.qbk

[/==============================================================================
    Copyright (C) 2001-2010 Joel de Guzman
    Copyright (C) 2001-2005 Dan Marsden
    Copyright (C) 2001-2010 Thomas Heller

    Distributed under the Boost Software License, Version 1.0. (See accompanying
    file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
===============================================================================/]

[section Actor]

The `Actor` is the main concept behind the library. Actors are function objects.
An actor can accept 0 to `BOOST_PHOENIX_LIMIT` arguments.

[note You can set `BOOST_PHOENIX_LIMIT`, the predefined maximum arity an
actor can take. By default, `BOOST_PHOENIX_LIMIT` is set to 10.]

Phoenix supplies an `actor` class template whose specializations
model the `Actor` concept.  `actor` has one template parameter, `Expr`,
that supplies the underlying expression to evaluate.

    template <typename Expr>
    struct actor
    {
        return_type
        operator()() const;

        template <typename T0>
        return_type
        operator()(T0& _0) const;

        template <typename T0, typename T1>
        return_type
        operator()(T0& _0, T1& _1) const;

        //...
    };

The actor class accepts the arguments through a set of function call operators
for 0 to `BOOST_PHOENIX_LIMIT` arities (Don't worry about the details, for now. Note, for example,
that we skimp over the details regarding `return_type`). The arguments are passed through to
the evaluation mechanism. For more information see [link phoenix.inside.actor Inside Actors].

[endsect]
Commit	Line	Data
7c673cae FG	1	[/==============================================================================
	2	Copyright (C) 2001-2010 Joel de Guzman
	3	Copyright (C) 2001-2005 Dan Marsden
	4	Copyright (C) 2001-2010 Thomas Heller
	5
	6	Distributed under the Boost Software License, Version 1.0. (See accompanying
	7	file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
	8	===============================================================================/]
	9
	10	[section Actor]
	11
	12	The `Actor` is the main concept behind the library. Actors are function objects.
	13	An actor can accept 0 to `BOOST_PHOENIX_LIMIT` arguments.
	14
	15	[note You can set `BOOST_PHOENIX_LIMIT`, the predefined maximum arity an
	16	actor can take. By default, `BOOST_PHOENIX_LIMIT` is set to 10.]
	17
	18	Phoenix supplies an `actor` class template whose specializations
	19	model the `Actor` concept. `actor` has one template parameter, `Expr`,
	20	that supplies the underlying expression to evaluate.
	21
	22	template <typename Expr>
	23	struct actor
	24	{
	25	return_type
	26	operator()() const;
	27
	28	template <typename T0>
	29	return_type
	30	operator()(T0& _0) const;
	31
	32	template <typename T0, typename T1>
	33	return_type
	34	operator()(T0& _0, T1& _1) const;
	35
	36	//...
	37	};
	38
	39	The actor class accepts the arguments through a set of function call operators
	40	for 0 to `BOOST_PHOENIX_LIMIT` arities (Don't worry about the details, for now. Note, for example,
	41	that we skimp over the details regarding `return_type`). The arguments are passed through to
	42	the evaluation mechanism. For more information see [link phoenix.inside.actor Inside Actors].
	43
	44	[endsect]
	45