/*
 * This source code is released into the public domain.
 */

module;

#include <algorithm>
#include <locale>
#include <ranges>
#include <string>
#include <utility>

export module nihil.util:next_word;

import :skipws;

namespace nihil {

/*
 * Return the next word from a string_view.  Skips leading whitespace, so
 * calling this repeatedly will return each word from the string.
 */

export template<typename Char> [[nodiscard]]
auto next_word(std::basic_string_view<Char> text,
	       std::locale const &locale = std::locale())
	-> std::pair<std::basic_string_view<Char>,
		     std::basic_string_view<Char>>
{
	text = skipws(text, locale);

	auto is_space = ctype_is(std::ctype_base::space, locale);
	auto split_pos = std::ranges::find_if(text, is_space);

	return {{std::ranges::begin(text), split_pos},
		{split_pos, std::ranges::end(text)}};
}

export template<typename Char>
auto next_word(std::basic_string_view<Char> *text,
	       std::locale const &locale = std::locale())
	-> std::basic_string_view<Char>
{
	auto [word, rest] = next_word(*text, locale);
	*text = rest;
	return word;
}

} // namespace nihil