156 lines
4.1 KiB
Plaintext
156 lines
4.1 KiB
Plaintext
[#before_6]
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['Definitions before section 6.]
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#include <boost/metaparse/string.hpp>
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#include <boost/metaparse/int_.hpp>
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#include <boost/metaparse/build_parser.hpp>
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using namespace boost::metaparse;
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using exp_parser1 = build_parser<int_>;
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#include <boost/metaparse/entire_input.hpp>
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using exp_parser2 = build_parser<entire_input<int_>>;
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#include <boost/metaparse/token.hpp>
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using exp_parser3 = build_parser<entire_input<token<int_>>>;
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#include <boost/metaparse/lit_c.hpp>
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#include <boost/metaparse/sequence.hpp>
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using exp_parser4 = build_parser<sequence<token<int_>, token<lit_c<'+'>>, token<int_>>>;
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#include <metashell/formatter.hpp>
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using int_token = token<int_>;
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using plus_token = token<lit_c<'+'>>;
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using exp_parser5 = build_parser<sequence<int_token, plus_token, int_token>>;
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#include <boost/metaparse/transform.hpp>
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#include <boost/mpl/plus.hpp>
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#include <boost/mpl/at.hpp>
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template <class Vector>
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struct eval_plus :
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boost::mpl::plus<
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typename boost::mpl::at_c<Vector, 0>::type,
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typename boost::mpl::at_c<Vector, 2>::type
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> {};
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#include <boost/mpl/quote.hpp>
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using exp_parser6 =
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build_parser<
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transform<
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sequence<int_token, plus_token, int_token>,
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boost::mpl::quote1<eval_plus>
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>
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>;
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#include <boost/metaparse/any.hpp>
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using exp_parser7 =
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build_parser<
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sequence<
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int_token, /* The first <number> */
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repeated<sequence<plus_token, int_token>> /* The "+ <number>" elements */
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>
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>;
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using temp_result = exp_parser7::apply<BOOST_METAPARSE_STRING("1 + 2 + 3 + 4")>::type;
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#include <boost/mpl/fold.hpp>
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using vector_of_numbers =
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boost::mpl::vector<
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boost::mpl::int_<2>,
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boost::mpl::int_<5>,
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boost::mpl::int_<6>
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>;
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template <class Vector>
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struct sum_vector :
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boost::mpl::fold<
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Vector,
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boost::mpl::int_<0>,
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boost::mpl::lambda<
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boost::mpl::plus<boost::mpl::_1, boost::mpl::_2>
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>::type
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>
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{};
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template <class Sum, class Item>
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struct sum_items :
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boost::mpl::plus<
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Sum,
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typename boost::mpl::at_c<Item, 1>::type
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>
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{};
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using exp_parser8 =
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build_parser<
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sequence<
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int_token, /* parse the first <number> */
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transform<
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repeated<sequence<plus_token, int_token>>, /* parse the "+ <number>" elements */
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/* lambda expression summarising the "+ <number>" elements using fold */
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boost::mpl::lambda<
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/* The folding expression we have just created */
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boost::mpl::fold<
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boost::mpl::_1, /* the argument of the lambda expression, the result */
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/* of the repeated<...> parser */
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boost::mpl::int_<0>,
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boost::mpl::quote2<sum_items>
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>
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>::type
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>
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>
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>;
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using exp_parser9 =
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build_parser<
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transform<
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/* What we had so far */
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sequence<
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int_token,
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transform<
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repeated<sequence<plus_token, int_token>>,
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boost::mpl::lambda<
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boost::mpl::fold<
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boost::mpl::_1,
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boost::mpl::int_<0>,
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boost::mpl::quote2<sum_items>
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>
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>::type
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>
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>,
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boost::mpl::quote1<sum_vector> /* summarise the vector of numbers */
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>
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>;
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#include <boost/metaparse/foldl.hpp>
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using exp_parser10 =
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build_parser<
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transform<
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sequence<
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int_token,
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foldl<
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sequence<plus_token, int_token>,
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boost::mpl::int_<0>,
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boost::mpl::quote2<sum_items>
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>
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>,
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boost::mpl::quote1<sum_vector>>
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>;
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#include <boost/metaparse/foldl_start_with_parser.hpp>
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using exp_parser11 =
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build_parser<
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foldl_start_with_parser<
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sequence<plus_token, int_token>, /* apply this parser repeatedly */
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int_token, /* use this parser to get the initial value */
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boost::mpl::quote2<sum_items> /* use this function to add a new value to the summary */
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>
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>;
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