spaces.qbk
1.05 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
[#spaces]
[section spaces]
[h1 Synopsis]
struct spaces;
This is a [link parser parser].
[h1 Description]
`spaces` accepts any number of whitespace characters. It requires at least one
to be present.
[h1 Header]
#include <boost/metaparse/spaces.hpp>
[h1 Expression semantics]
spaces
is equivalent to
repeated1<space>
[h1 Example]
#include <boost/metaparse/spaces.hpp>
#include <boost/metaparse/start.hpp>
#include <boost/metaparse/string.hpp>
#include <boost/metaparse/is_error.hpp>
#include <boost/metaparse/get_remaining.hpp>
#include <type_traits>
using namespace boost::metaparse;
static_assert(
std::is_same<
BOOST_METAPARSE_STRING("foo"),
get_remaining<spaces::apply<BOOST_METAPARSE_STRING(" foo"), start>>::type
>::type::value,
"it should consume all whitespaces at the beginning of the input"
);
static_assert(
is_error<spaces::apply<BOOST_METAPARSE_STRING("x"), start>>::type::value,
"it should return an error when the input does not begin with a whitespace"
);
[endsect]