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7c673cae FG |
1 | [#lit_c] |
2 | [section lit_c] | |
3 | ||
4 | [h1 Synopsis] | |
5 | ||
6 | template <char C> | |
7 | struct lit; | |
8 | ||
9 | This is a [link parser parser]. | |
10 | ||
11 | [table Arguments | |
12 | [[Name] [Type]] | |
13 | [[`C`] [`char` value]] | |
14 | ] | |
15 | ||
16 | [h1 Description] | |
17 | ||
18 | Parser accepting only the `C` character. The result of parsing is the accepted | |
19 | character. | |
20 | ||
21 | [h1 Header] | |
22 | ||
23 | #include <boost/metaparse/lit_c.hpp> | |
24 | ||
25 | [h1 Expression semantics] | |
26 | ||
27 | For any `c` character the following are equivalent: | |
28 | ||
29 | lit_c<c> | |
30 | ||
31 | lit<boost::mpl::char_<c>> | |
32 | ||
33 | [h1 Example] | |
34 | ||
35 | #include <boost/metaparse/lit_c.hpp> | |
36 | #include <boost/metaparse/start.hpp> | |
37 | #include <boost/metaparse/string.hpp> | |
38 | #include <boost/metaparse/is_error.hpp> | |
39 | #include <boost/metaparse/get_result.hpp> | |
40 | ||
41 | using namespace boost::metaparse; | |
42 | ||
43 | static_assert( | |
44 | is_error<lit_c<'x'>::apply<BOOST_METAPARSE_STRING("a"), start>>::type::value, | |
45 | "a different character should be an error" | |
46 | ); | |
47 | ||
48 | static_assert( | |
49 | is_error<lit_c<'x'>::apply<BOOST_METAPARSE_STRING(""), start>>::type::value, | |
50 | "empty input should be an error" | |
51 | ); | |
52 | ||
53 | static_assert( | |
54 | get_result< | |
55 | lit_c<'x'>::apply<BOOST_METAPARSE_STRING("x"), start> | |
56 | >::type::value == 'x', | |
57 | "result of parsing should be the accepted character" | |
58 | ); | |
59 | ||
60 | [endsect] | |
61 |