mirror of
https://github.com/boostorg/hana.git
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2c86ba2390
- Rename fold{l,r,l1,r1} to fold.{right,left} with overloads.
- Rename foldlM/foldrM to monadic_fold.{left,right}
- Add no-state variants of the monadic folds
- Improve the fold's documentation
- Deprecate the previous folds; they'll be removed soon
Fixes #18.
103 lines
2.2 KiB
C++
103 lines
2.2 KiB
C++
/*
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@copyright Louis Dionne 2015
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Distributed under the Boost Software License, Version 1.0.
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(See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
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*/
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#include <boost/hana/assert.hpp>
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#include <boost/hana/config.hpp>
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#include <boost/hana/core/datatype.hpp>
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#include <boost/hana/integral_constant.hpp>
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#include <boost/hana/maybe.hpp>
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#include <boost/hana/string.hpp>
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#include <type_traits>
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using namespace boost::hana;
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int main() {
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{
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//! [BOOST_HANA_STRING]
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BOOST_HANA_CONSTEXPR_LAMBDA auto str = BOOST_HANA_STRING("abcdef");
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static_assert(std::is_same<datatype_t<decltype(str)>, String>{}, "");
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//! [BOOST_HANA_STRING]
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}{
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//! [string]
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constexpr auto str = string<'a', 'b', 'c', 'd', 'e', 'f'>;
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static_assert(std::is_same<datatype_t<decltype(str)>, String>{}, "");
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//! [string]
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}{
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//! [comparable]
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BOOST_HANA_CONSTANT_CHECK(
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BOOST_HANA_STRING("abcdef") == BOOST_HANA_STRING("abcdef")
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);
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BOOST_HANA_CONSTANT_CHECK(
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BOOST_HANA_STRING("abcdef") != BOOST_HANA_STRING("abef")
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);
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//! [comparable]
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}{
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//! [orderable]
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BOOST_HANA_CONSTANT_CHECK(
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BOOST_HANA_STRING("abc") < BOOST_HANA_STRING("bcd")
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);
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BOOST_HANA_CONSTANT_CHECK(
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BOOST_HANA_STRING("abcd") > BOOST_HANA_STRING("abc")
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);
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//! [orderable]
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}{
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//! [foldable]
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auto sum_string = [](auto str) {
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return fold.left(str, int_<0>, [](auto sum, auto c) {
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constexpr int i = value(c) - 48; // convert character to decimal
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return sum + int_<i>;
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});
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};
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BOOST_HANA_CONSTANT_CHECK(
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sum_string(BOOST_HANA_STRING("1234")) == int_<1 + 2 + 3 + 4>
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);
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//! [foldable]
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}{
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//! [iterable]
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BOOST_HANA_CONSTANT_CHECK(!is_empty(BOOST_HANA_STRING("abcd")));
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BOOST_HANA_CONSTANT_CHECK(is_empty(BOOST_HANA_STRING("")));
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BOOST_HANA_CONSTANT_CHECK(BOOST_HANA_STRING("abcd")[int_<2>] == char_<'c'>);
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auto is_vowel = [](auto c) {
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return c ^in^ BOOST_HANA_STRING("aeiouy");
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};
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BOOST_HANA_CONSTANT_CHECK(
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drop_while(BOOST_HANA_STRING("aioubcd"), is_vowel) == BOOST_HANA_STRING("bcd")
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);
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//! [iterable]
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}{
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//! [searchable]
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BOOST_HANA_CONSTANT_CHECK(char_<'c'> ^in^ BOOST_HANA_STRING("abcde"));
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BOOST_HANA_CONSTANT_CHECK(!(char_<'z'> ^in^ BOOST_HANA_STRING("abcde")));
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BOOST_HANA_CONSTANT_CHECK(
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find(BOOST_HANA_STRING("abcxefg"), char_<'x'>) == just(char_<'x'>)
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);
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//! [searchable]
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}
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}
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