generators.ixx

module;

#include <experimental/generator>
#include <stdexcept>

export module Utils.Generators;

export
{
	namespace utils
	{
		namespace generators
		{

			// Lambda mutation is acctually a function call from c++14.
			auto fibonacci()
			{
				return [i = 1ULL, y = 1ULL]() mutable {
					if( y < i ) {
						throw std::runtime_error( "fibonacci: last possible iteration reached" );
					}
					auto ret = i;
					i        = y;
					y += ret;
					return ret;
				};
			}

			// Lambda mutation is acctually a function call from c++14.
			auto counter( int start = 0 )
			{
				return [i = start]() mutable { return i++; };
			}

			std::experimental::generator< int > co_counter( const int &start = 0 )
			{
				int c{ start };
				while( true )
					co_yield c++;
			}

		} // namespace generators
	}   // namespace utils
}