boost-react-native-bundle
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Boost library as in https://sourceforge.net/projects/boost/files/boost/1.57.0/
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<!--
Copyright 2003, Eric Friedman, Itay Maman.
Copyright 2013-2014 Antony Polukhin.
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)
-->
<header name="boost/variant/apply_visitor.hpp">
<namespace name="boost">
<class name="apply_visitor_delayed_t">
<purpose>Adapts a visitor for use as a function object.</purpose>
<description>
<simpara>Adapts the function given at construction for use as a
function object. This is useful, for example, when one needs to
operate on each element of a sequence of variant objects using a
standard library algorithm such as
<code>std::for_each</code>.</simpara>
<simpara>See the "visitor-only" form of
<code><functionname>apply_visitor</functionname></code> for a simple
way to create <code>apply_visitor_delayed_t</code> objects.</simpara>
</description>
<template>
<template-type-parameter name="Visitor"/>
</template>
<typedef name="result_type">
<type>typename Visitor::result_type</type>
</typedef>
<constructor specifiers="explicit">
<parameter name="visitor">
<paramtype>Visitor &</paramtype>
</parameter>
<effects>
<simpara>Constructs the function object with the given
visitor.</simpara>
</effects>
</constructor>
<method-group name="function object interface">
<overloaded-method name="operator()">
<signature>
<template>
<template-type-parameter name="Variant"/>
</template>
<type>result_type</type>
<parameter name="operand">
<paramtype>Variant &</paramtype>
</parameter>
</signature>
<signature>
<template>
<template-type-parameter name="Variant1"/>
<template-type-parameter name="Variant2"/>
</template>
<type>result_type</type>
<parameter name="operand1">
<paramtype>Variant1 &</paramtype>
</parameter>
<parameter name="operand2">
<paramtype>Variant2 &</paramtype>
</parameter>
</signature>
<purpose>Function call operator.</purpose>
<description>
<simpara>Invokes
<code><functionname>apply_visitor</functionname></code> on the
stored visitor using the given operands.</simpara>
</description>
</overloaded-method>
</method-group>
</class>
<overloaded-function name="apply_visitor">
<signature>
<template>
<template-type-parameter name="Visitor"/>
<template-type-parameter name="Variant"/>
</template>
<type>typename Visitor::result_type</type>
<parameter name="visitor">
<paramtype>Visitor &</paramtype>
</parameter>
<parameter name="operand">
<paramtype>Variant &</paramtype>
</parameter>
</signature>
<signature>
<template>
<template-type-parameter name="Visitor"/>
<template-type-parameter name="Variant"/>
</template>
<type>typename Visitor::result_type</type>
<parameter name="visitor">
<paramtype>const Visitor &</paramtype>
</parameter>
<parameter name="operand">
<paramtype>Variant &</paramtype>
</parameter>
</signature>
<signature>
<template>
<template-type-parameter name="BinaryVisitor"/>
<template-type-parameter name="Variant1"/>
<template-type-parameter name="Variant2"/>
</template>
<type>typename BinaryVisitor::result_type</type>
<parameter name="visitor">
<paramtype>BinaryVisitor &</paramtype>
</parameter>
<parameter name="operand1">
<paramtype>Variant1 &</paramtype>
</parameter>
<parameter name="operand2">
<paramtype>Variant2 &</paramtype>
</parameter>
</signature>
<signature>
<template>
<template-type-parameter name="BinaryVisitor"/>
<template-type-parameter name="Variant1"/>
<template-type-parameter name="Variant2"/>
</template>
<type>typename BinaryVisitor::result_type</type>
<parameter name="visitor">
<paramtype>const BinaryVisitor &</paramtype>
</parameter>
<parameter name="operand1">
<paramtype>Variant1 &</paramtype>
</parameter>
<parameter name="operand2">
<paramtype>Variant2 &</paramtype>
</parameter>
</signature>
<signature>
<template>
<template-type-parameter name="MultiVisitor"/>
<template-type-parameter name="Variant1"/>
<template-type-parameter name="Variant2"/>
<template-type-parameter name="Variant3"/>
</template>
<type>typename MultiVisitor::result_type</type>
<parameter name="visitor">
<paramtype>MultiVisitor &</paramtype>
</parameter>
<parameter name="operand1">
<paramtype>Variant1 &</paramtype>
</parameter>
<parameter name="operand2">
<paramtype>Variant2 &</paramtype>
</parameter>
<parameter name="operand3">
<paramtype>Variant3 &</paramtype>
</parameter>
<parameter name="other_operands">
<paramtype>...</paramtype>
</parameter>
</signature>
<signature>
<template>
<template-type-parameter name="MultiVisitor"/>
<template-type-parameter name="Variant1"/>
<template-type-parameter name="Variant2"/>
<template-type-parameter name="Variant3"/>
</template>
<type>typename MultiVisitor::result_type</type>
<parameter name="visitor">
<paramtype>const MultiVisitor &</paramtype>
</parameter>
<parameter name="operand1">
<paramtype>Variant1 &</paramtype>
</parameter>
<parameter name="operand2">
<paramtype>Variant2 &</paramtype>
</parameter>
<parameter name="operand3">
<paramtype>Variant3 &</paramtype>
</parameter>
<parameter name="other_operands">
<paramtype>...</paramtype>
</parameter>
</signature>
<signature>
<template>
<template-type-parameter name="Visitor"/>
</template>
<type><classname>apply_visitor_delayed_t</classname><Visitor></type>
<parameter name="visitor">
<paramtype>Visitor &</paramtype>
</parameter>
</signature>
<purpose>
<simpara>Allows compile-time checked type-safe application of the
given visitor to the content of the given variant, ensuring that all
types are handled by the visitor.</simpara>
</purpose>
<description>
<simpara>The behavior of <code>apply_visitor</code> is dependent on
the number of arguments on which it operates (i.e., other than the
visitor). The function behaves as follows:
<itemizedlist>
<listitem>Overloads accepting one operand invoke the unary function
call operator of the given visitor on the content of the given
<code><classname>variant</classname></code> operand.</listitem>
<listitem>Overloads accepting two operands invoke the binary
function call operator of the given visitor on the content of
the given <code><classname>variant</classname></code>
operands.</listitem>
<listitem>Overloads accepting three or more operands invoke the
function call operator of the given visitor on the content of
the given <code><classname>variant</classname></code>
operands. Maximum amount of parameters controlled by
<code><emphasis role="bold"><macroname>BOOST_VARAINT_MAX_MULTIVIZITOR_PARAMS</macroname></emphasis></code>
macro. Those functions are actually defined in <xref linkend="header.boost.variant.multivisitors_hpp"/>.</listitem>
<listitem>The overload accepting only a visitor returns a
<classname alt="boost::apply_visitor_delayed_t">generic function object</classname>
that accepts either one or two arguments and invokes
<code><functionname>apply_visitor</functionname></code> using
these arguments and <code>visitor</code>, thus behaving as
specified above. (This behavior is particularly useful, for
example, when one needs to operate on each element of a sequence
of variant objects using a standard library
algorithm.)</listitem>
</itemizedlist>
</simpara>
</description>
<returns>
<simpara>The overloads acccepting operands return the result of
applying the given visitor to the content of the given operands.
The overload accepting only a visitor return a function object, thus
delaying application of the visitor to any operands.</simpara>
</returns>
<requires>
<simpara>The given visitor must fulfill the
<link linkend="variant.concepts.static-visitor"><emphasis>StaticVisitor</emphasis></link>
concept requirements with respect to each of the bounded types of the
given <code>variant</code>.</simpara>
</requires>
<throws>
<simpara>The overloads accepting operands throw only if the given
visitor throws when applied. The overload accepting only a visitor
will not throw. (Note, however, that the returned
<classname alt="boost::apply_visitor_delayed_t">function object</classname>
may throw when invoked.)</simpara>
</throws>
</overloaded-function>
</namespace>
</header>