Recursive parsers wip

libs/parser/include/psemek/parser/combinators.hpp

@@ -84,6 +84,49 @@ namespace psemek::parser
 			return res;
 		}
 
+		template <typename R, typename Gen>
+		struct recursive_helper
+		{
+			using P = decltype(std::declval<Gen>()(std::declval<parser_ref<recursive_helper>>()));
+			P p;
+
+			recursive_helper(Gen && gen)
+				: p(std::forward<Gen>(gen)(parser_ref<recursive_helper>{this}))
+			{}
+
+			template <typename Buffer>
+			result<R> apply(Buffer & buf) const
+			{
+				return p.apply(buf);
+			}
+
+			R parse(std::string_view text) const
+			{
+				return p.parse(text);
+			}
+		};
+
+		template <typename R, typename Gen>
+		struct recursive_impl
+		{
+			std::unique_ptr<recursive_helper<R, Gen>> p;
+
+			recursive_impl(Gen && gen)
+				: p(std::make_unique<recursive_helper<R, Gen>>(std::forward<Gen>(gen)))
+			{}
+
+			template <typename Buffer>
+			result<R> apply(Buffer & buf) const
+			{
+				return p->apply(buf);
+			}
+
+			R parse(std::string_view text) const
+			{
+				return p->parse(text);
+			}
+		};
+
 	}
 
 	template <typename P, typename F>
@@ -261,4 +304,10 @@ namespace psemek::parser
 		return fold(std::forward<P>(p), [](auto const &, auto const &){ return skip_token{}; }, skip_token{});
 	}
 
+	template <typename R, typename Gen>
+	auto recursive(Gen && gen)
+	{
+		return detail::recursive_impl<R, Gen>(std::forward<Gen>(gen));
+	}
+
 }

libs/parser/include/psemek/parser/parser.hpp

@@ -105,6 +105,23 @@ namespace psemek::parser
 			}
 		};
 
+		template <typename P>
+		struct parser_ref
+		{
+			P * p;
+
+			template <typename Buffer>
+			auto apply(Buffer & buf) const
+			{
+				return p->apply(buf);
+			}
+
+			auto parse(std::string_view text) const
+			{
+				return p->parse(text);
+			}
+		};
+
 	}
 
 	struct error