From afcc62fc75ef3610e60bb46a9a576ef4ed385e38 Mon Sep 17 00:00:00 2001
From: rbock <rbock@eudoxos.de>
Date: Wed, 15 Jan 2014 19:42:14 +0100
Subject: [PATCH] Added interpreters for a bunch of functions and table aliases

---
 include/sqlpp11/any.h            | 24 +++++----
 include/sqlpp11/avg.h            | 24 +++++----
 include/sqlpp11/count.h          | 24 +++++----
 include/sqlpp11/exists.h         | 26 ++++++----
 include/sqlpp11/from.h           | 10 ----
 include/sqlpp11/functions.h      | 57 ++++++++++++---------
 include/sqlpp11/max.h            | 24 +++++----
 include/sqlpp11/min.h            | 24 +++++----
 include/sqlpp11/some.h           | 24 +++++----
 include/sqlpp11/sum.h            | 24 +++++----
 include/sqlpp11/table.h          | 38 +-------------
 include/sqlpp11/table_alias.h    | 88 ++++++++++++++++++++++++++++++++
 include/sqlpp11/text.h           | 12 -----
 include/sqlpp11/verbatim_table.h | 19 ++++---
 include/sqlpp11/where.h          |  5 --
 tests/InterpretTest.cpp          | 17 ++++++
 16 files changed, 266 insertions(+), 174 deletions(-)
 create mode 100644 include/sqlpp11/table_alias.h

diff --git a/include/sqlpp11/any.h b/include/sqlpp11/any.h
index 12393dff..35883da3 100644
--- a/include/sqlpp11/any.h
+++ b/include/sqlpp11/any.h
@@ -71,20 +71,24 @@ namespace sqlpp
 			any_t& operator=(any_t&&) = default;
 			~any_t() = default;
 
-			template<typename Db>
-				void serialize(std::ostream& os, Db& db) const
-				{
-					static_assert(Db::_supports_any, "any() not supported by current database");
-					os << "ANY(";
-					_select.serialize(os, db);
-					os << ")";
-				}
-
-		private:
 			Select _select;
 		};
 	}
 
+	template<typename Context, typename Select>
+		struct interpreter_t<Context, detail::any_t<Select>>
+		{
+			using T = detail::any_t<Select>;
+
+			static Context& _(const T& t, Context& context)
+			{
+				context << "ANY(";
+				interpret(t._select, context);
+				context << ")";
+				return context;
+			}
+		};
+
 	template<typename T>
 	auto any(T&& t) -> typename detail::any_t<typename operand_t<T, is_select_t>::type>
 	{
diff --git a/include/sqlpp11/avg.h b/include/sqlpp11/avg.h
index b0782dd3..fcbddabe 100644
--- a/include/sqlpp11/avg.h
+++ b/include/sqlpp11/avg.h
@@ -70,20 +70,24 @@ namespace sqlpp
 			avg_t& operator=(avg_t&&) = default;
 			~avg_t() = default;
 
-			template<typename Db>
-				void serialize(std::ostream& os, Db& db) const
-				{
-					static_assert(Db::_supports_avg, "avg() not supported by current database");
-					os << "AVG(";
-					_expr.serialize(os, db);
-					os << ")";
-				}
-
-		private:
 			Expr _expr;
 		};
 	}
 
+	template<typename Context, typename Expr>
+		struct interpreter_t<Context, detail::avg_t<Expr>>
+		{
+			using T = detail::avg_t<Expr>;
+
+			static Context& _(const T& t, Context& context)
+			{
+				context << "AVG(";
+				interpret(t._expr, context);
+				context << ")";
+				return context;
+			}
+		};
+
 	template<typename T>
 	auto avg(T&& t) -> typename detail::avg_t<typename operand_t<T, is_value_t>::type>
 	{
diff --git a/include/sqlpp11/count.h b/include/sqlpp11/count.h
index 28e331e4..fe9c59fc 100644
--- a/include/sqlpp11/count.h
+++ b/include/sqlpp11/count.h
@@ -70,20 +70,24 @@ namespace sqlpp
 			count_t& operator=(count_t&&) = default;
 			~count_t() = default;
 
-			template<typename Db>
-				void serialize(std::ostream& os, Db& db) const
-				{
-					static_assert(Db::_supports_count, "count() not supported by current database");
-					os << "COUNT(";
-					_expr.serialize(os, db);
-					os << ")";
-				}
-
-		private:
 			Expr _expr;
 		};
 	}
 
+	template<typename Context, typename Expr>
+		struct interpreter_t<Context, detail::count_t<Expr>>
+		{
+			using T = detail::count_t<Expr>;
+
+			static Context& _(const T& t, Context& context)
+			{
+				context << "COUNT(";
+				interpret(t._expr, context);
+				context << ")";
+				return context;
+			}
+		};
+
 	template<typename T>
 	auto count(T&& t) -> typename detail::count_t<typename operand_t<T, is_value_t>::type>
 	{
diff --git a/include/sqlpp11/exists.h b/include/sqlpp11/exists.h
index 0451ba36..52de3480 100644
--- a/include/sqlpp11/exists.h
+++ b/include/sqlpp11/exists.h
@@ -27,7 +27,6 @@
 #ifndef SQLPP_EXISTS_H
 #define SQLPP_EXISTS_H
 
-#include <sstream>
 #include <sqlpp11/boolean.h>
 
 namespace sqlpp
@@ -70,20 +69,25 @@ namespace sqlpp
 			exists_t& operator=(exists_t&&) = default;
 			~exists_t() = default;
 
-			template<typename Db>
-				void serialize(std::ostream& os, Db& db) const
-				{
-					static_assert(Db::_supports_exists, "exists() not supported by current database");
-					os << "EXISTS(";
-					_select.serialize(os, db);
-					os << ")";
-				}
-
-		private:
 			Select _select;
 		};
 	}
 
+	template<typename Context, typename Select>
+		struct interpreter_t<Context, detail::exists_t<Select>>
+		{
+			using T = detail::exists_t<Select>;
+
+			static Context& _(const T& t, Context& context)
+			{
+				context << "EXISTS(";
+				interpret(t._select, context);
+				context << ")";
+				return context;
+			}
+		};
+
+
 	template<typename T>
 	auto exists(T&& t) -> typename detail::exists_t<typename operand_t<T, is_select_t>::type>
 	{
diff --git a/include/sqlpp11/from.h b/include/sqlpp11/from.h
index a20f2e60..91d73c04 100644
--- a/include/sqlpp11/from.h
+++ b/include/sqlpp11/from.h
@@ -61,16 +61,6 @@ namespace sqlpp
 					_dynamic_tables.emplace_back(std::forward<Table>(table));
 				}
 
-			template<typename Db>
-				void serialize(std::ostream& os, Db& db) const
-				{
-					if (sizeof...(TableOrJoin) == 0 and _dynamic_tables.empty())
-						return;
-					os << " FROM ";
-					detail::serialize_tuple(os, db, _tables, ',');
-					_dynamic_tables.serialize(os, db, sizeof...(TableOrJoin) == 0);
-				}
-
 			std::tuple<TableOrJoin...> _tables;
 			detail::serializable_list<Database> _dynamic_tables;
 		};
diff --git a/include/sqlpp11/functions.h b/include/sqlpp11/functions.h
index 8b00e25b..645b04a8 100644
--- a/include/sqlpp11/functions.h
+++ b/include/sqlpp11/functions.h
@@ -27,10 +27,8 @@
 #ifndef SQLPP_FUNCTIONS_H
 #define SQLPP_FUNCTIONS_H
 
-#include <sstream>
 #include <sqlpp11/parameter.h>
 #include <sqlpp11/parameter_list.h>
-#include <sqlpp11/type_traits.h>
 #include <sqlpp11/column_types.h>
 #include <sqlpp11/in.h>
 #include <sqlpp11/exists.h>
@@ -57,12 +55,6 @@ namespace sqlpp
 	{
 		using _value_type = ValueType;
 
-		template<typename Db>
-		void serialize(std::ostream& os, const Db& db) const
-		{
-			os << _verbatim;
-		}
-
 		verbatim_t(const std::string& verbatim): _verbatim(verbatim) {}
 		verbatim_t(std::string&& verbatim): _verbatim(std::forward<std::string>(verbatim)) {}
 		verbatim_t(const verbatim_t&) = default;
@@ -74,6 +66,18 @@ namespace sqlpp
 		std::string _verbatim;
 	};
 
+	template<typename Context, typename ValueType>
+		struct interpreter_t<Context, verbatim_t<ValueType>>
+		{
+			using T = verbatim_t<ValueType>;
+
+			static Context& _(const T& t, Context& context)
+			{
+				context << t._verbatim;
+				return context;
+			}
+		};
+
 	template<typename ValueType, typename StringType>
 		auto verbatim(StringType&& s) -> verbatim_t<ValueType>
 		{
@@ -93,26 +97,31 @@ namespace sqlpp
 		{
 			using _container_t = Container;
 			using _value_type = typename operand_t<typename _container_t::value_type, is_value_t>::type::_value_type;
-			using _iterator = decltype(std::begin(std::declval<_container_t>()));
-
-			template<typename Db>
-				void serialize(std::ostream& os, const Db& db) const
-				{
-					bool first = true;
-					for (const auto& entry: _container)
-					{
-						if (first)
-							first = false;
-						else
-							os << ',';
-
-						value(entry).serialize(os, db);
-					}
-				}
 
 			_container_t _container;
 		};
 
+	template<typename Context, typename Container>
+		struct interpreter_t<Context, value_list_t<Container>>
+		{
+			using T = value_list_t<Container>;
+
+			static Context& _(const T& t, Context& context)
+			{
+				bool first = true;
+				for (const auto& entry: t._container)
+				{
+					if (first)
+						first = false;
+					else
+						context << ',';
+
+					interpret(value(entry), context);
+				}
+				return context;
+			}
+		};
+
 	template<typename Container>
 	auto value_list(Container&& c) -> value_list_t<typename std::decay<Container>::type>
 	{
diff --git a/include/sqlpp11/max.h b/include/sqlpp11/max.h
index 1310e674..524d84e8 100644
--- a/include/sqlpp11/max.h
+++ b/include/sqlpp11/max.h
@@ -70,20 +70,24 @@ namespace sqlpp
 			max_t& operator=(max_t&&) = default;
 			~max_t() = default;
 
-			template<typename Db>
-				void serialize(std::ostream& os, Db& db) const
-				{
-					static_assert(Db::_supports_max, "max not supported by current database");
-					os << "MAX(";
-					_expr.serialize(os, db);
-					os << ")";
-				}
-
-		private:
 			Expr _expr;
 		};
 	}
 
+	template<typename Context, typename Expr>
+		struct interpreter_t<Context, detail::max_t<Expr>>
+		{
+			using T = detail::max_t<Expr>;
+
+			static Context& _(const T& t, Context& context)
+			{
+				context << "MAX(";
+				interpret(t._expr, context);
+				context << ")";
+				return context;
+			}
+		};
+
 	template<typename T>
 	auto max(T&& t) -> typename detail::max_t<typename operand_t<T, is_value_t>::type>
 	{
diff --git a/include/sqlpp11/min.h b/include/sqlpp11/min.h
index 2e0f6205..20ca7f54 100644
--- a/include/sqlpp11/min.h
+++ b/include/sqlpp11/min.h
@@ -70,20 +70,24 @@ namespace sqlpp
 			min_t& operator=(min_t&&) = default;
 			~min_t() = default;
 
-			template<typename Db>
-				void serialize(std::ostream& os, Db& db) const
-				{
-					static_assert(Db::_supports_min, "min not supported by current database");
-					os << "MIN(";
-					_expr.serialize(os, db);
-					os << ")";
-				}
-
-		private:
 			Expr _expr;
 		};
 	}
 
+	template<typename Context, typename Expr>
+		struct interpreter_t<Context, detail::min_t<Expr>>
+		{
+			using T = detail::min_t<Expr>;
+
+			static Context& _(const T& t, Context& context)
+			{
+				context << "MIN(";
+				interpret(t._expr, context);
+				context << ")";
+				return context;
+			}
+		};
+
 	template<typename T>
 	auto min(T&& t) -> typename detail::min_t<typename operand_t<T, is_value_t>::type>
 	{
diff --git a/include/sqlpp11/some.h b/include/sqlpp11/some.h
index f4c8bd40..768279c9 100644
--- a/include/sqlpp11/some.h
+++ b/include/sqlpp11/some.h
@@ -71,20 +71,24 @@ namespace sqlpp
 			some_t& operator=(some_t&&) = default;
 			~some_t() = default;
 
-			template<typename Db>
-				void serialize(std::ostream& os, Db& db) const
-				{
-					static_assert(Db::_supports_some, "some() not supported by current database");
-					os << "SOME(";
-					_select.serialize(os, db);
-					os << ")";
-				}
-
-		private:
 			Select _select;
 		};
 	}
 
+	template<typename Context, typename Select>
+		struct interpreter_t<Context, detail::some_t<Select>>
+		{
+			using T = detail::some_t<Select>;
+
+			static Context& _(const T& t, Context& context)
+			{
+				context << "SOME(";
+				interpret(t._select, context);
+				context << ")";
+				return context;
+			}
+		};
+
 	template<typename T>
 	auto some(T&& t) -> typename detail::some_t<typename operand_t<T, is_select_t>::type>
 	{
diff --git a/include/sqlpp11/sum.h b/include/sqlpp11/sum.h
index 7d11201e..0e260b3b 100644
--- a/include/sqlpp11/sum.h
+++ b/include/sqlpp11/sum.h
@@ -70,20 +70,24 @@ namespace sqlpp
 			sum_t& operator=(sum_t&&) = default;
 			~sum_t() = default;
 
-			template<typename Db>
-				void serialize(std::ostream& os, Db& db) const
-				{
-					static_assert(Db::_supports_sum, "sum not supported by current database");
-					os << "SUM(";
-					_expr.serialize(os, db);
-					os << ")";
-				}
-
-		private:
 			Expr _expr;
 		};
 	}
 
+	template<typename Context, typename Expr>
+		struct interpreter_t<Context, detail::sum_t<Expr>>
+		{
+			using T = detail::sum_t<Expr>;
+
+			static Context& _(const T& t, Context& context)
+			{
+				context << "SUM(";
+				interpret(t._expr, context);
+				context << ")";
+				return context;
+			}
+		};
+
 	template<typename T>
 	auto sum(T&& t) -> typename detail::sum_t<typename operand_t<T, is_value_t>::type>
 	{
diff --git a/include/sqlpp11/table.h b/include/sqlpp11/table.h
index 1287868d..1c2106ed 100644
--- a/include/sqlpp11/table.h
+++ b/include/sqlpp11/table.h
@@ -27,8 +27,7 @@
 #ifndef SQLPP_TABLE_H
 #define SQLPP_TABLE_H
 
-#include <ostream>
-#include <sqlpp11/alias.h>
+#include <sqlpp11/table_alias.h>
 #include <sqlpp11/no_value.h>
 #include <sqlpp11/column.h>
 #include <sqlpp11/detail/set.h>
@@ -81,40 +80,7 @@ namespace sqlpp
 			}
 
 		template<typename AliasProvider>
-			struct alias_t: public ColumnSpec::_name_t::template _member_t<column_t<AliasProvider, ColumnSpec>>...
-		{
-			using _is_table = std::true_type;
-			using _table_set = detail::set<alias_t>;
-
-			struct _value_type: Table::_value_type
-			{
-				using _is_expression = std::false_type;
-				using _is_named_expression = copy_type_trait<Table, is_value_t>;
-				using _is_alias = std::true_type;
-			};
-
-			using _name_t = typename AliasProvider::_name_t;
-			using _all_of_t = std::tuple<column_t<AliasProvider, ColumnSpec>...>;
-
-			alias_t(const Table& table):
-				_table(table)
-			{}
-
-			alias_t(Table&& table):
-				_table(std::move(table))
-			{}
-
-			template<typename Db>
-				void serialize(std::ostream& os, Db& db) const
-				{
-					os << "("; _table.serialize(os, db); os << ") AS " << _name_t::_get_name();
-				}
-
-			Table _table;
-		};
-
-		template<typename AliasProvider>
-			alias_t<AliasProvider> as(const AliasProvider&) const
+			table_alias_t<typename std::decay<AliasProvider>::type, Table, ColumnSpec...> as(const AliasProvider&) const
 			{
 				return {*static_cast<const Table*>(this)};
 			}
diff --git a/include/sqlpp11/table_alias.h b/include/sqlpp11/table_alias.h
new file mode 100644
index 00000000..879f067f
--- /dev/null
+++ b/include/sqlpp11/table_alias.h
@@ -0,0 +1,88 @@
+/*
+ * Copyright (c) 2013, Roland Bock
+ * All rights reserved.
+ * 
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ * 
+ *   Redistributions of source code must retain the above copyright notice, this
+ *   list of conditions and the following disclaimer.
+ * 
+ *   Redistributions in binary form must reproduce the above copyright notice, this
+ *   list of conditions and the following disclaimer in the documentation and/or
+ *   other materials provided with the distribution.
+ * 
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
+ * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef SQLPP_TABLE_ALIAS_H
+#define SQLPP_TABLE_ALIAS_H
+
+#include <string>
+#include <ostream>
+#include <sqlpp11/column.h>
+#include <sqlpp11/alias.h>
+#include <sqlpp11/detail/set.h>
+#include <sqlpp11/type_traits.h>
+
+namespace sqlpp
+{
+	struct table_alias_base_t {};
+
+	template<typename AliasProvider, typename Table, typename... ColumnSpec>
+		struct table_alias_t: public table_alias_base_t, public ColumnSpec::_name_t::template _member_t<column_t<AliasProvider, ColumnSpec>>...
+	{
+		//FIXME: Need to add join functionality
+		using _is_table = std::true_type;
+		using _table_set = detail::set<table_alias_t>;
+
+		struct _value_type: Table::_value_type
+		{
+			using _is_expression = std::false_type;
+			using _is_named_expression = copy_type_trait<Table, is_value_t>;
+			using _is_alias = std::true_type;
+		};
+
+		using _name_t = typename AliasProvider::_name_t;
+		using _all_of_t = std::tuple<column_t<AliasProvider, ColumnSpec>...>;
+
+		table_alias_t(Table table):
+			_table(table)
+		{}
+
+		template<typename Db>
+			void serialize(std::ostream& os, Db& db) const
+			{
+				os << "("; _table.serialize(os, db); os << ") AS " << _name_t::_get_name();
+			}
+
+		Table _table;
+	};
+
+	template<typename Context, typename X>
+		struct interpreter_t<Context, X, typename std::enable_if<std::is_base_of<table_alias_base_t, X>::value, void>::type>
+		{
+			using T = X;
+
+			static Context& _(const T& t, Context& context)
+			{
+				context << "(";
+				interpret(t._table, context);
+				context << ") AS " << T::_name_t::_get_name();
+				return context;
+			}
+		};
+
+}
+
+#endif
+
diff --git a/include/sqlpp11/text.h b/include/sqlpp11/text.h
index 35252a92..36098e39 100644
--- a/include/sqlpp11/text.h
+++ b/include/sqlpp11/text.h
@@ -80,12 +80,6 @@ namespace sqlpp
 					return *this;
 				}
 
-				template<typename Db>
-					void serialize(std::ostream& os, Db& db) const
-					{
-						os << value();
-					}
-
 				bool is_null() const
 			 	{ 
 					return _is_null; 
@@ -142,12 +136,6 @@ namespace sqlpp
 					_len = 0;
 				}
 
-				template<typename Db>
-					void serialize(std::ostream& os, Db& db) const
-					{
-						os << value();
-					}
-
 				bool operator==(const _cpp_value_type& rhs) const { return value() == rhs; }
 				bool operator!=(const _cpp_value_type& rhs) const { return not operator==(rhs); }
 
diff --git a/include/sqlpp11/verbatim_table.h b/include/sqlpp11/verbatim_table.h
index c82de2e1..67851a7f 100644
--- a/include/sqlpp11/verbatim_table.h
+++ b/include/sqlpp11/verbatim_table.h
@@ -62,15 +62,22 @@ namespace sqlpp
 		verbatim_table_t& operator=(verbatim_table_t&& rhs) = default;
 		~verbatim_table_t() = default;
 
-		template<typename Db>
-			void serialize(std::ostream& os, Db& db) const
-			{
-				os << _name;
-			}
-
 		std::string _name;
 	};
 
+	template<typename Context>
+		struct interpreter_t<Context, verbatim_table_t>
+		{
+			using T = verbatim_table_t;
+
+			static Context& _(const T& t, Context& context)
+			{
+				context << t._name;
+				return context;
+			}
+		};
+
+
 	verbatim_table_t verbatim_table(std::string name)
 	{
 		return { name };
diff --git a/include/sqlpp11/where.h b/include/sqlpp11/where.h
index 0aa5e936..df927fa3 100644
--- a/include/sqlpp11/where.h
+++ b/include/sqlpp11/where.h
@@ -58,11 +58,6 @@ namespace sqlpp
 					_dynamic_expressions.emplace_back(std::forward<E>(expr));
 				}
 
-			template<typename Db>
-				void serialize(std::ostream& os, Db& db) const
-				{
-				}
-
 			_parameter_tuple_t _expressions;
 			detail::serializable_list<Database> _dynamic_expressions;
 		};
diff --git a/tests/InterpretTest.cpp b/tests/InterpretTest.cpp
index 9cefaea6..1bb48793 100644
--- a/tests/InterpretTest.cpp
+++ b/tests/InterpretTest.cpp
@@ -75,5 +75,22 @@ int main()
 	interpret(remove_from(t).where(t.alpha == sqlpp::tvin(0)), printer).flush();
 	interpret(remove_from(t).using_(t).where(t.alpha == sqlpp::tvin(0)), printer).flush();
 
+	// functions
+	interpret(sqlpp::value(7), printer).flush();
+	interpret(sqlpp::verbatim<sqlpp::detail::integral>("irgendwas integrales"), printer).flush();
+	interpret(sqlpp::value_list(std::vector<int>({1,2,3,4,5,6,8})), printer).flush();
+	interpret(exists(select(t.alpha).from(t)), printer).flush();
+	interpret(any(select(t.alpha).from(t)), printer).flush();
+	interpret(some(select(t.alpha).from(t)), printer).flush();
+	interpret(count(t.alpha), printer).flush();
+	interpret(min(t.alpha), printer).flush();
+	interpret(max(t.alpha), printer).flush();
+	interpret(avg(t.alpha), printer).flush();
+	interpret(sum(t.alpha), printer).flush();
+	interpret(sqlpp::verbatim_table("whatever"), printer).flush();
+
+	interpret(t.as(t.alpha), printer).flush();
+	interpret(t.as(t.alpha).beta, printer).flush();
+
 	return 0;
 }