projects / ceph.git / blame
| Commit | Line | Data |
|---|---|---|
| 7c673cae FG |
1 | [#repeated_one_of] |
| 2 | [section repeated_one_of] | |
| 3 | ||
| 4 | [h1 Synopsis] | |
| 5 | ||
| 6 | template <class P1, class P2, /* ... */, class Pn> | |
| 7 | struct repeated_one_of1; | |
| 8 | ||
| 9 | [table Arguments | |
| 10 | [[Name] [Type]] | |
| 11 | [[`P1` .. `Pn`][[link parser parser]s]] | |
| 12 | ] | |
| 13 | ||
| 14 | This is a [link parser_combinator parser combinator]. | |
| 15 | ||
| 16 | [h1 Description] | |
| 17 | ||
| 18 | It applies the `P1` ... `Pn` parsers repeatedly as long as any of them accepts | |
| 19 | the input. In each iteration the parsers are tried in order and the first one | |
| 20 | accepting the input is used, therefore in case of ambiguous grammars the result | |
| 21 | of parsing depends on the order of the `P1` ... `Pn` parsers. The result of | |
| 22 | parsing with this [link parser_combinator parser combinator] is a sequence of | |
| 23 | the individual parsing results. | |
| 24 | ||
| 25 | When none of the `P1` ... `Pn` parsers accept the input in the first iteration, | |
| 26 | `repeated_one_of` accepts the input and the result of parsing is an empty | |
| 27 | sequence. | |
| 28 | ||
| 29 | The maximum number of accepted parsers is defined by the | |
| 30 | `BOOST_METAPARSE_LIMIT_ONE_OF_SIZE` macro. Its default value is 20. | |
| 31 | ||
| 32 | [h1 Header] | |
| 33 | ||
| 34 | #include <boost/metaparse/repeated_one_of.hpp> | |
| 35 | ||
| 36 | [h1 Expression semantics] | |
| 37 | ||
| 38 | For any `p1`, ..., `pn` parsers | |
| 39 | ||
| 40 | repeated_one_of<p1, /* ... */, pn> | |
| 41 | ||
| 42 | is equivalent to | |
| 43 | ||
| 44 | repeated<one_of<p1, /* ... */, pn>> | |
| 45 | ||
| 46 | [h1 Example] | |
| 47 | ||
| 48 | #include <boost/metaparse/repeated_one_of.hpp> | |
| 49 | #include <boost/metaparse/lit_c.hpp> | |
| 50 | #include <boost/metaparse/start.hpp> | |
| 51 | #include <boost/metaparse/string.hpp> | |
| 52 | #include <boost/metaparse/get_result.hpp> | |
| 53 | ||
| 54 | #include <boost/mpl/equal.hpp> | |
| 55 | #include <boost/mpl/vector.hpp> | |
| 56 | #include <boost/mpl/char.hpp> | |
| 57 | ||
| 58 | using namespace boost::metaparse; | |
| 59 | ||
| 60 | using as_and_bs = repeated_one_of<lit_c<'a'>, lit_c<'b'>>; | |
| 61 | ||
| 62 | static_assert( | |
| 63 | boost::mpl::equal< | |
| 64 | get_result<as_and_bs::apply<BOOST_METAPARSE_STRING("abaab"), start>>::type, | |
| 65 | boost::mpl::vector< | |
| 66 | boost::mpl::char_<'a'>, | |
| 67 | boost::mpl::char_<'b'>, | |
| 68 | boost::mpl::char_<'a'>, | |
| 69 | boost::mpl::char_<'a'>, | |
| 70 | boost::mpl::char_<'b'> | |
| 71 | > | |
| 72 | >::type::value, | |
| 73 | "the result of parsing should be the list of results" | |
| 74 | ); | |
| 75 | ||
| 76 | static_assert( | |
| 77 | boost::mpl::equal< | |
| 78 | get_result<as_and_bs::apply<BOOST_METAPARSE_STRING("x"), start>>::type, | |
| 79 | boost::mpl::vector<> | |
| 80 | >::type::value, | |
| 81 | "repeated_one_of should accept the input when it" | |
| 82 | " can't parse anything with digit_val" | |
| 83 | ); | |
| 84 | ||
| 85 | [endsect] | |
| 86 |