F consolidation

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include/caosdb/data_type.h

@@ -19,6 +19,13 @@
  *
  */
 
+/**
+ * DataTypes have 2 dimensions: They may be atomic or reference typed, and they
+ * may be scalar or list valued.  If they are atomic, they have an
+ * AtomicDataType.  If they are reference typed, the reference name can be
+ * obtained with GetName().
+ */
+
 #ifndef CAOSDB_DATA_TYPE_H
 #define CAOSDB_DATA_TYPE_H
 #include "caosdb/protobuf_helper.h"         // for ProtoMessageWrapper
@@ -144,6 +151,22 @@ public:
   DataType(const std::string &data_type) : DataType() {
     this->wrapped->mutable_reference_data_type()->set_name(data_type);
   }
+
+  inline static auto ListOf(const AtomicDataType &atomic_data_type)
+    -> DataType {
+    DataType result;
+    result.wrapped->mutable_list_data_type()->set_atomic_data_type(
+      static_cast<ProtoAtomicDataType>(atomic_data_type));
+    return result;
+  }
+  inline static auto ListOf(const std::string reference_data_type) -> DataType {
+    DataType result;
+    result.wrapped->mutable_list_data_type()
+      ->mutable_reference_data_type()
+      ->set_name(reference_data_type);
+    return result;
+  }
+
   [[nodiscard]] inline auto IsAtomic() const noexcept -> bool {
     return this->wrapped->data_type_case() == DataTypeCase::kAtomicDataType;
   }