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- [#repeated_one_of1]
- [section repeated_one_of1]
- [h1 Synopsis]
- template <class... Ps>
- struct repeated_one_of1;
- This is a [link parser_combinator parser combinator].
- [table Arguments
- [[Name] [Type]]
- [[`Ps`] [[link parser parser]s]]
- ]
- [h1 Description]
- It applies the `Ps...` parsers repeatedly as long as any of them accepts the
- input. In each iteration the parsers are tried in order and the first one
- accepting the input is used, therefore in case of ambiguous grammars the result
- of parsing depends on the order of the `Ps...` parsers. The result of parsing
- with this [link parser_combinator parser combinator] is a sequence of the
- individual parsing results.
- When none of the `Ps...` parsers accept the input in the first iteration,
- `repeated_one_of1` rejects the input.
- On compilers, which are not C++11-compliant, the maximum number of accepted
- parsers is defined by the `BOOST_METAPARSE_LIMIT_ONE_OF_SIZE` macro. Its default
- value is 20.
- [h1 Header]
- #include <boost/metaparse/repeated_one_of1.hpp>
- [h1 Expression semantics]
- For any `p1`, ..., `pn` parsers
- repeated_one_of1<p1, /* ... */, pn>
- is equivalent to
- repeated1<one_of<p1, /* ... */, pn>>
- [h1 Example]
- #include <boost/metaparse/repeated_one_of1.hpp>
- #include <boost/metaparse/lit_c.hpp>
- #include <boost/metaparse/start.hpp>
- #include <boost/metaparse/string.hpp>
- #include <boost/metaparse/get_result.hpp>
- #include <boost/metaparse/is_error.hpp>
-
- #include <boost/mpl/equal.hpp>
- #include <boost/mpl/vector.hpp>
- #include <boost/mpl/char.hpp>
-
- using namespace boost::metaparse;
-
- using as_and_bs = repeated_one_of1<lit_c<'a'>, lit_c<'b'>>;
-
- static_assert(
- boost::mpl::equal<
- get_result<as_and_bs::apply<BOOST_METAPARSE_STRING("abaab"), start>>::type,
- boost::mpl::vector<
- boost::mpl::char_<'a'>,
- boost::mpl::char_<'b'>,
- boost::mpl::char_<'a'>,
- boost::mpl::char_<'a'>,
- boost::mpl::char_<'b'>
- >
- >::type::value,
- "the result of parsing should be the list of results"
- );
-
- static_assert(
- is_error<as_and_bs::apply<BOOST_METAPARSE_STRING("x"), start>>::type::value,
- "repeated_one_of1 should reject the input when it"
- " can't parse anything with digit_val"
- );
- [endsect]
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