Boost C++ Libraries

...one of the most highly regarded and expertly designed C++ library projects in the world. — Herb Sutter and Andrei Alexandrescu, C++ Coding Standards

This is an older version of Boost and was released in 2013. The current version is 1.89.0.

fold

fold

Description

Returns the result type of fold.

Synopsis

template<
    typename Sequence,
    typename State,
    typename F>
struct fold
{
    typedef unspecified type;
};

Table 1.44. Parameters

Parameter	Requirement	Description
`Sequence`	A model of Forward Sequence	The sequence to iterate
`State`	Any type	The initial state for the first application of `F`
`F`	`boost::result_of<F(S,E)>::type` is the return type of `f(s,e)` with current state `s` of type `S`, and an element `e` of type `E` in `seq`	The operation to be applied on traversal

Expression Semantics

fold<Sequence, State, F>::type

Return type: Any type

Semantics: Returns the result of applying fold to a sequence of type Sequence, with an initial state of type State and binary function object or function pointer of type F.

Complexity

Linear, exactly result_of::size<Sequence>::value applications of F.

Header

#include <boost/fusion/algorithm/iteration/fold.hpp>
#include <boost/fusion/include/fold.hpp>