From d957e8c0aedf33ac96a9802bfe95e0fd02100ea4 Mon Sep 17 00:00:00 2001
From: rbock <rbock@eudoxos.de>
Date: Sun, 12 Jan 2014 12:22:15 +0100
Subject: [PATCH] Added interpreter to select, select_flag_list,
 select_expression_list

---
 include/sqlpp11/noop.h                   |  14 ++-
 include/sqlpp11/select.h                 |  79 +++++++++++------
 include/sqlpp11/select_expression_list.h | 105 ++++++++++++++---------
 include/sqlpp11/select_flag_list.h       |  63 ++++++++++----
 tests/InterpretTest.cpp                  |   3 +
 5 files changed, 175 insertions(+), 89 deletions(-)

diff --git a/include/sqlpp11/noop.h b/include/sqlpp11/noop.h
index d63bb31a..09124887 100644
--- a/include/sqlpp11/noop.h
+++ b/include/sqlpp11/noop.h
@@ -33,11 +33,19 @@ namespace sqlpp
 {
 	struct noop 
 	{
-		template<typename Db>
-			void serialize(std::ostream& os, Db& db) const
-			{}
 	};
 
+	template<typename Context>
+		struct interpreter_t<Context, noop>
+		{
+			using T = noop;
+
+			static Context& _(const T& t, Context& context)
+			{
+				return context;
+			}
+		};
+
 	template<typename T>
 	struct is_noop: std::is_same<T, noop> {};
 
diff --git a/include/sqlpp11/select.h b/include/sqlpp11/select.h
index 0616f7d3..99d4710c 100644
--- a/include/sqlpp11/select.h
+++ b/include/sqlpp11/select.h
@@ -547,32 +547,6 @@ namespace sqlpp
 							*this).as(aliasProvider);
 				}
 
-			// Serialize
-			template<typename Db>
-				const select_t& serialize(std::ostream& os, Db& db) const
-				{
-					os << "SELECT ";
-
-					_flags.serialize(os, db);
-					_expression_list.serialize(os, db);
-					_from.serialize(os, db);
-					_where.serialize(os, db);
-					_group_by.serialize(os, db);
-					_having.serialize(os, db);
-					_order_by.serialize(os, db);
-					_limit.serialize(os, db);
-					_offset.serialize(os, db);
-
-					return *this;
-				}
-
-			template<typename Db>
-				select_t& serialize(std::ostream& os, Db& db)
-				{
-					const_cast<const select_t*>(this)->serialize(os, db);
-					return *this;
-				}
-
 			const typename ExpressionList::_dynamic_names_t& get_dynamic_names() const
 			{
 				return _expression_list._dynamic_expressions._dynamic_expression_names;
@@ -644,6 +618,59 @@ namespace sqlpp
 			Offset _offset;
 		};
 
+			template<typename Context, 
+				typename Database,
+				typename Flags,
+				typename ExpressionList,
+				typename From,
+				typename Where,
+				typename GroupBy,
+				typename Having,
+				typename OrderBy,
+				typename Limit,
+				typename Offset
+					>
+		struct interpreter_t<Context, select_t<Database,
+										 Flags, 
+										 ExpressionList, 
+										 From, 
+										 Where, 
+										 GroupBy, 
+										 Having, 
+										 OrderBy, 
+										 Limit, 
+										 Offset>>
+		{
+			using T = select_t<Database,
+										 Flags, 
+										 ExpressionList, 
+										 From, 
+										 Where, 
+										 GroupBy, 
+										 Having, 
+										 OrderBy, 
+										 Limit, 
+										 Offset>;
+
+			static Context& _(const T& t, Context& context)
+			{
+					context << "SELECT ";
+
+					interpret(t._flags, context);
+					interpret(t._expression_list, context);
+					interpret(t._from, context);
+					interpret(t._where, context);
+					interpret(t._group_by, context);
+					interpret(t._having, context);
+					interpret(t._order_by, context);
+					interpret(t._limit, context);
+					interpret(t._offset, context);
+
+					return context;
+			}
+		};
+
+
 	// construct select flag list
 	namespace detail
 	{
diff --git a/include/sqlpp11/select_expression_list.h b/include/sqlpp11/select_expression_list.h
index cb1b25c3..30b0b381 100644
--- a/include/sqlpp11/select_expression_list.h
+++ b/include/sqlpp11/select_expression_list.h
@@ -57,32 +57,27 @@ namespace sqlpp
 				using _value_type = typename T::_value_type;
 				using _name_t = typename T::_name_t;
 			};
+	}
 
-		template<typename Db>
-			struct dynamic_select_expression_list
-			{
-				using _names_t = std::vector<std::string>;
-				std::vector<detail::named_serializable_t<Db>> _dynamic_expressions;
-				_names_t _dynamic_expression_names;
+	template<typename Db>
+		struct dynamic_select_expression_list
+		{
+			using _names_t = std::vector<std::string>;
+			std::vector<detail::named_serializable_t<Db>> _dynamic_expressions;
+			_names_t _dynamic_expression_names;
 
-				template<typename Expr>
+			template<typename Expr>
 				void push_back(Expr&& expr)
 				{
 					_dynamic_expression_names.push_back(std::decay<Expr>::type::_name_t::_get_name());
 					_dynamic_expressions.emplace_back(std::forward<Expr>(expr));
 				}
-				void serialize(std::ostream& os, Db& db, bool first) const
-				{
-					for (const auto column : _dynamic_expressions)
-					{
-						if (not first)
-							os << ',';
-						column.serialize(os, db);
-						first = false;
-					}
-				}
 
-			};
+			bool empty() const
+			{
+				return _dynamic_expressions.empty();
+			}
+		};
 
 		template<>
 			struct dynamic_select_expression_list<void>
@@ -93,14 +88,38 @@ namespace sqlpp
 				template<typename T>
 					void push_back(const T&) {}
 
-				template<typename Db>
-					void serialize(std::ostream&, Db&, bool) const
-					{
-					}
-
+				static constexpr bool empty()
+				{
+					return true;
+				}
 			};
 
-	}
+	template<typename Context, typename Db>
+		struct interpreter_t<Context, dynamic_select_expression_list<Db>>
+		{
+			using T = dynamic_select_expression_list<Db>;
+
+			static Context& _(const T& t, Context& context)
+			{
+				for (const auto column : t._dynamic_expressions)
+				{
+					interpret(column, context);
+				}
+				return context;
+			}
+		};
+
+	template<typename Context>
+		struct interpreter_t<Context, dynamic_select_expression_list<void>>
+		{
+			using T = dynamic_select_expression_list<void>;
+
+			static Context& _(const T& t, Context& context)
+			{
+				return context;
+			}
+		};
+
 
 	template<typename Database, typename... NamedExpr>
 		struct select_expression_list_t<Database, std::tuple<NamedExpr...>>
@@ -109,6 +128,9 @@ namespace sqlpp
 			using _is_dynamic = typename std::conditional<std::is_same<Database, void>::value, std::false_type, std::true_type>::type;
 			using _parameter_tuple_t = std::tuple<NamedExpr...>;
 
+			// check for at least one expression
+			static_assert(_is_dynamic::value or sizeof...(NamedExpr), "at least one select expression required");
+
 			// check for duplicate select expressions
 			static_assert(not detail::has_duplicates<NamedExpr...>::value, "at least one duplicate argument detected");
 
@@ -135,7 +157,7 @@ namespace sqlpp
 				dynamic_result_row_t<make_field_t<NamedExpr>...>,
 				result_row_t<make_field_t<NamedExpr>...>>::type;
 
-			using _dynamic_names_t = typename detail::dynamic_select_expression_list<Database>::_names_t;
+			using _dynamic_names_t = typename dynamic_select_expression_list<Database>::_names_t;
 
 			template <typename Select>
 				using _pseudo_table_t = select_pseudo_table_t<Select, NamedExpr...>;
@@ -151,24 +173,23 @@ namespace sqlpp
 					_dynamic_expressions.push_back(std::forward<Expr>(namedExpr));
 				}
 
-			template<typename Db>
-				void serialize(std::ostream& os, Db& db) const
-				{
-					// check for at least one select expression
-					static_assert(_is_dynamic::value or sizeof...(NamedExpr), "at least one select expression required");
-
-					detail::serialize_tuple(os, db, _expressions, ',');
-					_dynamic_expressions.serialize(os, db, sizeof...(NamedExpr) == 0);
-				}
-
-			size_t _set_parameter_index(size_t index)
-			{
-				index = set_parameter_index(_expressions, index);
-				return index;
-			}
-
 			_parameter_tuple_t _expressions;
-			detail::dynamic_select_expression_list<Database> _dynamic_expressions;
+			dynamic_select_expression_list<Database> _dynamic_expressions;
+		};
+
+	template<typename Context, typename Database, typename... NamedExpr>
+		struct interpreter_t<Context, select_expression_list_t<Database, NamedExpr...>>
+		{
+			using T = select_expression_list_t<Database, NamedExpr...>;
+
+			static Context& _(const T& t, Context& context)
+			{
+				interpret_tuple(t._expressions, ',', context);
+				if (not t._dynamic_expressions.empty())
+					context << ',';
+				interpret(t._dynamic_expressions, context);
+				return context;
+			}
 		};
 
 }
diff --git a/include/sqlpp11/select_flag_list.h b/include/sqlpp11/select_flag_list.h
index 989f2d7a..44b10fa1 100644
--- a/include/sqlpp11/select_flag_list.h
+++ b/include/sqlpp11/select_flag_list.h
@@ -43,45 +43,57 @@ namespace sqlpp
 		{ 
 			using _is_select_flag = std::true_type; 
 		};
-
-		template<typename Db>
-			void serialize(std::ostream& os, const Db&) const
-			{
-				os << "ALL";
-			}
 	};
 	static constexpr all_t all = {};
 
+	template<typename Context>
+		struct interpreter_t<Context, all_t>
+		{
+			static Context& _(const all_t&, Context& context)
+			{
+				context << "ALL";
+				return context;
+			}
+		};
+
 	struct distinct_t
 	{
 		struct _value_type 
 		{ 
 			using _is_select_flag = std::true_type; 
 		};
-
-		template<typename Db>
-			void serialize(std::ostream& os, const Db&) const
-			{
-				os << "DISTINCT";
-			}
 	};
 	static constexpr distinct_t distinct = {};
 
+	template<typename Context>
+		struct interpreter_t<Context, distinct_t>
+		{
+			static Context& _(const distinct_t&, Context& context)
+			{
+				context << "DISTINCT";
+				return context;
+			}
+		};
+
 	struct straight_join_t
 	{
 		struct _value_type 
 		{ 
 			using _is_select_flag = std::true_type; 
 		};
-
-		template<typename Db>
-			void serialize(std::ostream& os, const Db&) const
-			{
-				os << "STRAIGHT_JOIN";
-			}
 	};
 	static constexpr straight_join_t straight_join = {};
 
+	template<typename Context>
+		struct interpreter_t<Context, straight_join_t>
+		{
+			static Context& _(const straight_join_t&, Context& context)
+			{
+				context << "STRAIGHT_JOIN";
+				return context;
+			}
+		};
+
 	// select_flag_list_t
 	template<typename... Flag>
 		struct select_flag_list_t<std::tuple<Flag...>>
@@ -105,6 +117,21 @@ namespace sqlpp
 			std::tuple<Flag...> _flags;
 		};
 
+	template<typename Context, typename... Flag>
+		struct interpreter_t<Context, select_flag_list_t<std::tuple<Flag...>>>
+		{
+			using T = select_flag_list_t<std::tuple<Flag...>>;
+
+			static Context& _(const T& t, Context& context)
+			{
+				interpret_tuple(t._flags, ' ', context);
+				if (sizeof...(Flag))
+					context << ' ';
+				return context;
+			}
+		};
+
+
 }
 
 #endif
diff --git a/tests/InterpretTest.cpp b/tests/InterpretTest.cpp
index 6c48d56b..229b4933 100644
--- a/tests/InterpretTest.cpp
+++ b/tests/InterpretTest.cpp
@@ -25,6 +25,7 @@
 
 #include "TabSample.h"
 #include "MockDb.h"
+#include <sqlpp11/select.h>
 
 #include <iostream>
 
@@ -41,5 +42,7 @@ int main()
 	sqlpp::text_operand o = {"kaesekuchen"};
 	interpret(t.beta + "kaesekuchen", printer).flush();
 
+	interpret(select(sqlpp::distinct, t.alpha, t.beta), printer).flush();
+
 	return 0;
 }