• Home
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
1[#repeated_one_of1]
2[section repeated_one_of1]
3
4[h1 Synopsis]
5
6  template <class... Ps>
7  struct repeated_one_of1;
8
9This is a [link parser_combinator parser combinator].
10
11[table Arguments
12  [[Name] [Type]]
13  [[`Ps`] [[link parser parser]s]]
14]
15
16[h1 Description]
17
18It applies the `Ps...` parsers repeatedly as long as any of them accepts the
19input. In each iteration the parsers are tried in order and the first one
20accepting the input is used, therefore in case of ambiguous grammars the result
21of parsing depends on the order of the `Ps...` parsers. The result of parsing
22with this [link parser_combinator parser combinator] is a sequence of the
23individual parsing results.
24
25When none of the `Ps...` parsers accept the input in the first iteration,
26`repeated_one_of1` rejects the input.
27
28On compilers, which are not C++11-compliant, the maximum number of accepted
29parsers is defined by the `BOOST_METAPARSE_LIMIT_ONE_OF_SIZE` macro. Its default
30value is 20.
31
32[h1 Header]
33
34  #include <boost/metaparse/repeated_one_of1.hpp>
35
36[h1 Expression semantics]
37
38For any `p1`, ..., `pn` parsers
39
40  repeated_one_of1<p1, /* ... */, pn>
41
42is equivalent to
43
44  repeated1<one_of<p1, /* ... */, pn>>
45
46[h1 Example]
47
48  #include <boost/metaparse/repeated_one_of1.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  #include <boost/metaparse/is_error.hpp>
54
55  #include <boost/mpl/equal.hpp>
56  #include <boost/mpl/vector.hpp>
57  #include <boost/mpl/char.hpp>
58
59  using namespace boost::metaparse;
60
61  using as_and_bs = repeated_one_of1<lit_c<'a'>, lit_c<'b'>>;
62
63  static_assert(
64    boost::mpl::equal<
65      get_result<as_and_bs::apply<BOOST_METAPARSE_STRING("abaab"), start>>::type,
66      boost::mpl::vector<
67        boost::mpl::char_<'a'>,
68        boost::mpl::char_<'b'>,
69        boost::mpl::char_<'a'>,
70        boost::mpl::char_<'a'>,
71        boost::mpl::char_<'b'>
72      >
73    >::type::value,
74    "the result of parsing should be the list of results"
75  );
76
77  static_assert(
78    is_error<as_and_bs::apply<BOOST_METAPARSE_STRING("x"), start>>::type::value,
79    "repeated_one_of1 should reject the input when it"
80    " can't parse anything with digit_val"
81  );
82
83[endsect]
84
85