Turned a few operators into free functions.

This might be problematic since they are not selective enough. In
particular, they even take the result values...

include/sqlpp11/bad_expression.h

@@ -0,0 +1,58 @@
+/*
+ * Copyright (c) 2013-2015, 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_BAD_EXPRESSION_H
+#define SQLPP_BAD_EXPRESSION_H
+
+#include <sqlpp11/portable_static_assert.h>
+#include <sqlpp11/type_traits.h>
+
+namespace sqlpp
+{
+  SQLPP_PORTABLE_STATIC_ASSERT(assert_valid_operands, "Invalid operand(s)");
+
+  template <typename ValueType>
+  struct bad_expression
+  {
+    template <typename... T>
+    bad_expression(T&&...)
+    {
+    }
+    using _traits = make_traits<ValueType, tag::is_expression>;
+    using _nodes = detail::type_vector<>;
+  };
+
+  template <typename Context, typename ValueType>
+  struct serializer_t<Context, bad_expression<ValueType>>
+  {
+    using _serialize_check = assert_valid_operands;
+    using T = bad_expression<ValueType>;
+
+    static Context& _(const T&, Context&);
+  };
+}
+
+#endif

include/sqlpp11/data_types/boolean/data_type.h

@@ -33,7 +33,7 @@ namespace sqlpp
 {
   struct boolean
   {
-    using _traits = make_traits<void, tag::is_value_type>;
+    // using _traits = make_traits<void, tag::is_value_type>;
     using _cpp_value_type = bool;
 
     template <typename T>

include/sqlpp11/data_types/boolean/expression_operators.h

@@ -27,39 +27,38 @@
 #ifndef SQLPP_BOOLEAN_EXPRESSION_OPERATORS_H
 #define SQLPP_BOOLEAN_EXPRESSION_OPERATORS_H
 
+#include <sqlpp11/operators.h>
+#include <sqlpp11/expression_return_types.h>
+#include <sqlpp11/operand_check.h>
 #include <sqlpp11/expression_operators.h>
 #include <sqlpp11/basic_expression_operators.h>
 
 namespace sqlpp
 {
-  template <typename Base>
-  struct expression_operators<Base, boolean> : public basic_expression_operators<Base, boolean>
+  template <typename Expression>
+  struct expression_operators<Expression, boolean> : public basic_expression_operators<Expression, boolean>
   {
-    template <typename T>
-    using _is_valid_operand = is_valid_operand<boolean, T>;
+  };
+
+  template <typename L, typename R>
+  struct return_type_and<L, R, binary_operand_check_t<L, is_boolean_t, R, is_boolean_t>>
+  {
+    using check = consistent_t;
+    using type = logical_and_t<wrap_operand_t<L>, wrap_operand_t<R>>;
+  };
+
+  template <typename L, typename R>
+  struct return_type_or<L, R, binary_operand_check_t<L, is_boolean_t, R, is_boolean_t>>
+  {
+    using check = consistent_t;
+    using type = logical_or_t<wrap_operand_t<L>, wrap_operand_t<R>>;
+  };
 
   template <typename T>
-    logical_and_t<Base, wrap_operand_t<T>> operator and(T t) const
+  struct return_type_not<T, unary_operand_check_t<T, is_boolean_t>>
   {
-      using rhs = wrap_operand_t<T>;
-      static_assert(_is_valid_operand<rhs>::value, "invalid rhs operand");
-
-      return {*static_cast<const Base*>(this), rhs{t}};
-    }
-
-    template <typename T>
-    logical_or_t<Base, wrap_operand_t<T>> operator or(T t) const
-    {
-      using rhs = wrap_operand_t<T>;
-      static_assert(_is_valid_operand<rhs>::value, "invalid rhs operand");
-
-      return {*static_cast<const Base*>(this), rhs{t}};
-    }
-
-    logical_not_t<Base> operator not() const
-    {
-      return {*static_cast<const Base*>(this)};
-    }
+    using check = consistent_t;
+    using type = logical_not_t<wrap_operand_t<T>>;
   };
 }
 

include/sqlpp11/expression_return_types.h

@@ -0,0 +1,65 @@
+/*
+ * Copyright (c) 2013-2015, 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_EXPRESSION_RETURN_TYPES_H
+#define SQLPP_EXPRESSION_RETURN_TYPES_H
+
+#include <sqlpp11/bad_expression.h>
+
+namespace sqlpp
+{
+  template <typename L, typename R, typename Enable = void>
+  struct return_type_and
+  {
+    using check = assert_valid_operands;
+    using type = bad_expression<boolean>;
+  };
+
+  template <typename L, typename R>
+  using return_type_and_t = typename return_type_and<L, R>::type;
+
+  template <typename L, typename R, typename Enable = void>
+  struct return_type_or
+  {
+    using check = assert_valid_operands;
+    using type = bad_expression<boolean>;
+  };
+
+  template <typename L, typename R>
+  using return_type_or_t = typename return_type_or<L, R>::type;
+
+  template <typename T, typename Enable = void>
+  struct return_type_not
+  {
+    using check = assert_valid_operands;
+    using type = bad_expression<boolean>;
+  };
+
+  template <typename T>
+  using return_type_not_t = typename return_type_not<T>::type;
+}
+
+#endif

include/sqlpp11/operand_check.h

@@ -0,0 +1,72 @@
+/*
+ * Copyright (c) 2013-2015, 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_OPERAND_CHECK_H
+#define SQLPP_OPERAND_CHECK_H
+
+#include <sqlpp11/wrap_operand.h>
+#include <sqlpp11/detail/enable_if.h>
+
+namespace sqlpp
+{
+  template <typename T, template <typename> class Pred, typename Enable = void>
+  struct unary_operand_check
+  {
+  };
+
+  template <typename T, template <typename> class Pred>
+  struct unary_operand_check<T, Pred, detail::enable_if_t<Pred<wrap_operand_t<T>>::value>>
+  {
+    using type = void;
+  };
+
+  template <typename T, template <typename> class Pred>
+  using unary_operand_check_t = typename unary_operand_check<T, Pred>::type;
+
+  template <typename L,
+            template <typename> class LPred,
+            typename R,
+            template <typename> class RPred,
+            typename Enable = void>
+  struct binary_operand_check
+  {
+  };
+
+  template <typename L, template <typename> class LPred, typename R, template <typename> class RPred>
+  struct binary_operand_check<L,
+                              LPred,
+                              R,
+                              RPred,
+                              detail::enable_if_t<LPred<wrap_operand_t<L>>::value and RPred<wrap_operand_t<R>>::value>>
+  {
+    using type = void;
+  };
+
+  template <typename L, template <typename> class LPred, typename R, template <typename> class RPred>
+  using binary_operand_check_t = typename binary_operand_check<L, LPred, R, RPred>::type;
+}
+
+#endif

include/sqlpp11/operators.h

@@ -0,0 +1,55 @@
+/*
+ * Copyright (c) 2013-2015, 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_OPERATORS_H
+#define SQLPP_OPERATORS_H
+
+#include <sqlpp11/wrap_operand.h>
+#include <sqlpp11/expression_return_types.h>
+
+namespace sqlpp
+{
+  template <typename L, typename R>
+  auto operator and(const L& l, const R& r) -> return_type_and_t<L, R>
+  {
+    return_type_and<L, R>::check::_();
+    return {wrap_operand_t<L>{l}, wrap_operand_t<R>{r}};
+  }
+  template <typename L, typename R>
+  auto operator or(const L& l, const R& r) -> return_type_or_t<L, R>
+  {
+    return_type_or<L, R>::check::_();
+    return {wrap_operand_t<L>{l}, wrap_operand_t<R>{r}};
+  }
+  template <typename T>
+  auto operator not(const T& t) -> return_type_not_t<T>
+  {
+    return_type_not<T>::check::_();
+    return {wrap_operand_t<T>{t}};
+  }
+}
+
+#endif

include/sqlpp11/type_traits.h

@@ -43,7 +43,7 @@ namespace sqlpp
     template <typename T, typename Enable = void>
     struct value_type_of_impl
     {
-      static_assert(wrong_t<value_type_of_impl>::value, "Attempting to optain value type from type without value_type");
+      static_assert(wrong_t<value_type_of_impl>::value, "Attempting to obtain value type from type without value_type");
     };
 
     template <typename T>

tests/BooleanExpression.cpp

@@ -33,9 +33,9 @@ int BooleanExpression(int, char**)
   MockDb db = {};
   test::TabBar t;
 
-  auto x = boolean_expression(db, t.alpha == 7);
+  auto x = boolean_expression(db, not(t.alpha == 7));
   x = sqlpp::boolean_expression<MockDb>(t.beta.like("%cheesecake"));
-  x = x and boolean_expression(db, t.gamma);
+  x = false or (x and boolean_expression(db, t.gamma));
 
   db(select(t.alpha).from(t).where(x));