record refactoring

include/matador/sql/field.hpp

@@ -3,6 +3,7 @@
 
 #include "matador/sql/any_type.hpp"
 #include "matador/sql/any_type_to_visitor.hpp"
+#include "matador/sql/data_type_traits.hpp"
 
 #include "matador/utils/types.hpp"
 
@@ -64,11 +65,13 @@ class field
 public:
   explicit field(std::string name);
   template<typename Type>
-  field(std::string name, Type value, int index = -1)
+  field(std::string name, Type value, size_t size = 0, int index = -1)
   : name_(std::move(name))
+  , size_(size)
   , index_(index)
   , value_(value)
   , type_(field_traits<Type>::type()) {}
+  field(std::string name, data_type_t data_type, size_t size = 0, int index = -1);
   field(const field &x) = default;
   field& operator=(const field &x) = default;
   field(field &&x) noexcept;
@@ -82,6 +85,7 @@ public:
   }
 
   [[nodiscard]] const std::string& name() const;
+  [[nodiscard]] size_t size() const;
   [[nodiscard]] int index() const;
 
   template<class Type>
@@ -104,9 +108,21 @@ public:
   friend std::ostream& operator<<(std::ostream &out, const field &col);
 
 private:
+  template<class Operator>
+  void process(Operator &op)
+  {
+    op.on_attribute(name_.c_str(), value_, field_type_to_data_type(type_), size_);
+  }
+
+private:
+  friend class record;
+
+  static data_type_t field_type_to_data_type(field_type type);
+
   std::string name_;
   int index_{-1};
   any_type value_;
+  size_t size_{};
   field_type type_;
 };