field.rb in red-arrow-0.12.0

- old
+ new
@@ -16,19 +16,103 @@
 # under the License.
 
 module Arrow
   class Field
     alias_method :initialize_raw, :initialize
-    def initialize(name, data_type)
-      case data_type
-      when String, Symbol
-        data_type_name = data_type.to_s.capitalize.gsub(/\AUint/, "UInt")
-        data_type_class_name = "#{data_type_name}DataType"
-        if Arrow.const_defined?(data_type_class_name)
-          data_type_class = Arrow.const_get(data_type_class_name)
-          data_type = data_type_class.new
+    private :initialize_raw
+
+    # Creates a new {Arrow::Field}.
+    #
+    # @overload initialize(name, data_type)
+    #
+    #   @param name [String, Symbol] The name of the field.
+    #
+    #   @param data_type [Arrow::DataType, Hash, String, Symbol] The
+    #     data type of the field.
+    #
+    #     You can specify data type as a description by `Hash`.
+    #
+    #     See {Arrow::DataType.resolve} how to specify data type
+    #     description.
+    #
+    #   @example Create a field with {Arrow::DataType}s
+    #     Arrow::Field.new("visible", Arrow::BooleanDataType.new)
+    #
+    #   @example Create a field with data type description
+    #     Arrow::Field.new("visible", :boolean)
+    #
+    #   @example Create a field with name as `Symbol`
+    #     Arrow::Field.new(:visible, :boolean)
+    #
+    # @overload initialize(description)
+    #
+    #   @param description [Hash] The description of the field.
+    #
+    #     Field description is a raw `Hash`. Field description must
+    #     have `:name` and `:data_type` values. `:name` is the name of
+    #     the field. `:data_type` is the data type of the field. You
+    #     can use {Arrow::DataType} or data type description as
+    #     `:data_type` value.
+    #
+    #     See {Arrow::DataType.resolve} how to specify data type
+    #     description.
+    #
+    #     There is a shortcut for convenience. If field description
+    #     doesn't have `:data_type`, all keys except `:name` are
+    #     processes as data type description. For example, the
+    #     following field descrptions are the same:
+    #
+    #     ```ruby
+    #     {name: "visible", data_type: {type: :boolean}}
+    #     {name: "visible", type: :boolean} # Shortcut version
+    #     ```
+    #
+    #   @option description [String, Symbol] :name The name of the field.
+    #
+    #   @option description [Arrow::DataType, Hash] :data_type The
+    #     data type of the field. You can specify data type description
+    #     by `Hash`.
+    #
+    #     See {Arrow::DataType.resolve} how to specify data type
+    #     description.
+    #
+    #   @example Create a field with {Arrow::DataType}s
+    #     Arrow::Field.new(name: "visible",
+    #                      data_type: Arrow::BooleanDataType.new)
+    #
+    #   @example Create a field with data type description
+    #     Arrow::Field.new(name: "visible", data_type: {type: :boolean}
+    #
+    #   @example Create a field with shortcut form
+    #     Arrow::Field.new(name: "visible", type: :boolean)
+    def initialize(*args)
+      n_args = args.size
+      case n_args
+      when 1
+        description = args[0]
+        name = nil
+        data_type = nil
+        data_type_description = {}
+        description.each do |key, value|
+          key = key.to_sym
+          case key
+          when :name
+            name = value
+          when :data_type
+            data_type = DataType.resolve(value)
+          else
+            data_type_description[key] = value
+          end
         end
+        data_type ||= DataType.resolve(data_type_description)
+      when 2
+        name = args[0]
+        data_type = DataType.resolve(args[1])
+      else
+        message = "wrong number of arguments (given #{n_args}, expected 1..2)"
+        raise ArgumentError, message
       end
+
       initialize_raw(name, data_type)
     end
   end
 end