75 lines
1.7 KiB
Plaintext
75 lines
1.7 KiB
Plaintext
[#repeated1]
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[section repeated1]
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[h1 Synopsis]
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template <class P>
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struct repeated1;
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This is a [link parser_combinator parser combinator].
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[table Arguments
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[[Name] [Type]]
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[[`P`] [[link parser parser]]]
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]
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[h1 Description]
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It applies `P` on the input string repeatedly as long as the parser accepts the
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input. The result of parsing is a sequence of the results of the individual
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applications of `P`.
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When `P` rejects the input for the first time, `repeated1` rejects it as well.
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At least one successful application of `P` is required for `repeated1` to accept
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the input.
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[h1 Header]
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#include <boost/metaparse/repeated1.hpp>
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[h1 Expression semantics]
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For any `p` parser the following are equivalent:
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repeated1<p>
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last_of<look_ahead<p>, repeated<p>>
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[h1 Example]
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#include <boost/metaparse/repeated1.hpp>
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#include <boost/metaparse/digit_val.hpp>
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#include <boost/metaparse/start.hpp>
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#include <boost/metaparse/string.hpp>
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#include <boost/metaparse/get_result.hpp>
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#include <boost/metaparse/is_error.hpp>
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#include <boost/mpl/equal.hpp>
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#include <boost/mpl/vector.hpp>
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#include <boost/mpl/int.hpp>
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using namespace boost::metaparse;
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using digits = repeated1<digit_val>;
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static_assert(
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boost::mpl::equal<
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get_result<digits::apply<BOOST_METAPARSE_STRING("1234"), start>>::type,
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boost::mpl::vector<
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boost::mpl::int_<1>,
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boost::mpl::int_<2>,
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boost::mpl::int_<3>,
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boost::mpl::int_<4>
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>
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>::type::value,
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"the result of parsing should be the list of digit values"
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);
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static_assert(
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is_error<digits::apply<BOOST_METAPARSE_STRING("x"), start>>::type::value,
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"repeated1 should reject the input when it can't parse anything with digit_val"
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);
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[endsect]
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