1[#alphanum]
2[section alphanum]
3
4[h1 Synopsis]
5
6  struct alphanum;
7
8This is a [link parser parser].
9
10[h1 Description]
11
12It accepts one character in the range `a-z`, `A-Z` or `0-9`. The
13result of the parser is the accepted character.
14
15[h1 Header]
16
17  #include <boost/metaparse/alphanum.hpp>
18
19[h1 Expression semantics]
20
21The following are equivalent:
22
23  alphanum
24
25  one_of<digit, letter>
26
27[h1 Example]
28
29  #include <boost/metaparse/alphanum.hpp>
30  #include <boost/metaparse/start.hpp>
31  #include <boost/metaparse/string.hpp>
32  #include <boost/metaparse/is_error.hpp>
33  #include <boost/metaparse/get_result.hpp>
34
35  using namespace boost::metaparse;
36
37  static_assert(
38    !is_error<alphanum::apply<BOOST_METAPARSE_STRING("0"), start>>::type::value,
39    "alphanum should accept a digit"
40  );
41
42  static_assert(
43    !is_error<alphanum::apply<BOOST_METAPARSE_STRING("x"), start>>::type::value,
44    "alphanum should accept a character"
45  );
46
47  static_assert(
48    get_result<
49      alphanum::apply<BOOST_METAPARSE_STRING("x"), start>
50    >::type::value == 'x',
51    "the result of parsing should be the character value"
52  );
53
54  static_assert(
55    is_error<alphanum::apply<BOOST_METAPARSE_STRING(","), start>>::type::value,
56    "alphanum should reject a comma"
57  );
58
59[endsect]
60
61