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hana/example/string.cpp
2015-02-01 21:02:18 -05:00

98 lines
2.6 KiB
C++

/*
@copyright Louis Dionne 2014
Distributed under the Boost Software License, Version 1.0.
(See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
*/
#include <boost/hana/assert.hpp>
#include <boost/hana/core/models.hpp>
#include <boost/hana/detail/constexpr.hpp>
#include <boost/hana/integral_constant.hpp>
#include <boost/hana/maybe.hpp>
#include <boost/hana/string.hpp>
using namespace boost::hana;
int main() {
{
//! [BOOST_HANA_STRING]
BOOST_HANA_CONSTEXPR_LAMBDA auto str = BOOST_HANA_STRING("abcdef");
BOOST_HANA_CONSTANT_CHECK(is_a<String>(str));
//! [BOOST_HANA_STRING]
}
{
//! [string]
constexpr auto str = string<'a', 'b', 'c', 'd', 'e', 'f'>;
BOOST_HANA_CONSTANT_CHECK(is_a<String>(str));
//! [string]
}
//! [comparable]
BOOST_HANA_CONSTANT_CHECK(
BOOST_HANA_STRING("abcdef") == BOOST_HANA_STRING("abcdef")
);
BOOST_HANA_CONSTANT_CHECK(
BOOST_HANA_STRING("abcdef") != BOOST_HANA_STRING("abef")
);
//! [comparable]
//! [orderable]
BOOST_HANA_CONSTANT_CHECK(
BOOST_HANA_STRING("abc") < BOOST_HANA_STRING("bcd")
);
BOOST_HANA_CONSTANT_CHECK(
BOOST_HANA_STRING("abcd") > BOOST_HANA_STRING("abc")
);
//! [orderable]
//! [constant]
/* not constexpr */ auto abcdef = BOOST_HANA_STRING("abcdef");
constexpr char const* s = value(abcdef);
static_assert(s[2] == 'c', "");
//! [constant]
//! [foldable]
auto sum_string = [](auto str) {
return foldl(str, int_<0>, [](auto sum, auto c) {
constexpr int i = value(c) - 48; // convert character to decimal
return sum + int_<i>;
});
};
BOOST_HANA_CONSTANT_CHECK(
sum_string(BOOST_HANA_STRING("1234")) == int_<1 + 2 + 3 + 4>
);
//! [foldable]
//! [iterable]
BOOST_HANA_CONSTANT_CHECK(!is_empty(BOOST_HANA_STRING("abcd")));
BOOST_HANA_CONSTANT_CHECK(is_empty(BOOST_HANA_STRING("")));
BOOST_HANA_CONSTANT_CHECK(BOOST_HANA_STRING("abcd")[int_<2>] == char_<'c'>);
auto is_vowel = [](auto c) {
return c ^in^ BOOST_HANA_STRING("aeiouy");
};
BOOST_HANA_CONSTANT_CHECK(
drop_while(BOOST_HANA_STRING("aioubcd"), is_vowel) == BOOST_HANA_STRING("bcd")
);
//! [iterable]
//! [searchable]
BOOST_HANA_CONSTANT_CHECK(char_<'c'> ^in^ BOOST_HANA_STRING("abcde"));
BOOST_HANA_CONSTANT_CHECK(!(char_<'z'> ^in^ BOOST_HANA_STRING("abcde")));
BOOST_HANA_CONSTANT_CHECK(
lookup(BOOST_HANA_STRING("abcxefg"), char_<'x'>) == just(char_<'x'>)
);
//! [searchable]
}