| Home | Libraries | People | FAQ | More

## Macro BOOST_VMD_TO_TUPLE

BOOST_VMD_TO_TUPLE — Converts a sequence to a Boost PP tuple whose elements are the elements of the sequence.

## Synopsis

    // In header: <boost/vmd/to_tuple.hpp>

    BOOST_VMD_TO_TUPLE(...)

## Description

... = Variadic parameters.

The first variadic parameter is required and is the sequence to convert.

Further optional variadic parameters can be return type parameters. Return type parameters allow each element in the sequence to be converted to a two-element tuple where the first tuple element is the type and the second tuple element is the element data.

The BOOST_VMD_RETURN_NO_TYPE, the default, does not return the type as part of each converted element but just the data. All of the rest return the type and data as the two-element tuple. If BOOST_VMD_RETURN_TYPE is specified the specific type of the element is returned in the tuple. If BOOST_VMD_RETURN_TYPE_ARRAY is specified an array type is returned if the element is an array, else a tuple type is returned if the element is a tuple, else the actual type is returned for non-tuple data. If BOOST_VMD_RETURN_TYPE_LIST is specified a list type is returned if the element is a list, else a tuple type is returned if the element is a tuple, else the actual type is returned for non-tuple data. If BOOST_VMD_RETURN_TYPE_TUPLE is specified a tuple type is returned for all tuple-like data, else the actual type is returned for non-tuple data. If more than one return type optional parameter is specified the last one specified determines the return type.

returns = A Boost PP tuple. If the sequence is empty the return is emptiness since an empty tuple does not exist. If an optional return type other than BOOST_VMD_RETURN_NO_TYPE is specified the type and the data of each element is returned as the tuple element. Otherwise just the data is returned as the tuple element, which is the default.