[String] Split methods and refactor

example/string.cpp

@@ -0,0 +1,108 @@
+/*
+@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]
+
+}
+
+}