chilon Code

#ifndef CHILON_DB_STATEMENT_HPP
#define CHILON_DB_STATEMENT_HPP

namespace chilon { namespace db {

namespace detail {
    template <int idx, class Tag, class Table>
    struct tag_to_index;

    template <int idx, class Tag, class... Columns>
    struct tag_to_index<idx, Tag, table<Columns...>>
      : tag_to_index<idx, Tag, type::list<Columns...>> {};

    template <int idx, class Tag, class Head, class... Tail>
    struct tag_to_index<idx, Tag, type::list<Head, Tail...>>
      : tag_to_index<idx + 1, Tag, type::list<Tail...>> {};

    template <int idx, class Tag, class SourceType, class... Tail>
    struct tag_to_index<idx, Tag, type::list<column<Tag, SourceType>, Tail...>>
      : type::head_i<idx> {};
}

// TODO: rename these to something
template <class Table, int... Columns>
struct columns_i {
    typedef Table table_type;
};

template <class Table, class... Tags>
struct columns {
    typedef Table table_type;
};

template <class Table, class... Tags>
struct tags {};

template <class Columns>
struct statement;

template <class Table, int... Columns>
struct statement<columns_i<Table, Columns...>> {
    enum { n_parameters = sizeof...(Columns) ? sizeof...(Columns) : Table::n_columns };

    typedef Table                                                 table_type;
    typedef type::view<typename Table::columns_type, Columns...>  column_view;
    typedef type::view<typename Table::types,        Columns...>  type_view;
};

template <class Table, class Tag>
struct tag_to_index : detail::tag_to_index<0, Tag, Table> {};

template <class Table, class... Tags>
struct statement<columns<Table, Tags...>>
  : statement<columns_i<Table, tag_to_index<Table, Tags>::value...>> {};

} }


#endif