relation.rb in rom-3.0.0.beta1

- old
+ new

@@ -1,5 +1,6 @@
+require 'rom/initializer'
 require 'rom/relation/class_interface'
 
 require 'rom/pipeline'
 require 'rom/mapper_registry'
 
@@ -27,58 +28,49 @@
   # provide extensions for those sub-classes but there is always a vanilla
   # relation instance stored in the schema registry.
   #
   # @api public
   class Relation
+    extend Initializer
     extend ClassInterface
 
-    include Options
     include Dry::Equalizer(:dataset)
     include Materializable
     include Pipeline
 
+    # @!attribute [r] dataset
+    #   @return [Object] dataset used by the relation provided by relation's gateway
+    #   @api public
+    param :dataset
+
     # @!attribute [r] mappers
     #   @return [MapperRegistry] an optional mapper registry (empty by default)
     option :mappers, reader: true, default: proc { MapperRegistry.new }
 
+    # @!attribute [r] schema
+    #   @return [Schema] relation schema, defaults to class-level canonical
+    #                    schema (if it was defined) and sets an empty one as
+    #                    the fallback
+    #   @api public
+    option :schema, reader: true, optional: true, default: -> relation {
+      relation.class.schema || Schema.define(Dry::Core::Inflector.underscore(relation.class.name || EMPTY_STRING).to_sym)
+    }
+
     # @!attribute [r] schema_hash
     #   @return [Object#[]] tuple processing function, uses schema or defaults to Hash[]
     #   @api private
     option :schema_hash, reader: true, default: -> relation {
       relation.schema? ? Types::Coercible::Hash.schema(relation.schema.to_h) : Hash
     }
 
-    # @!attribute [r] associations
-    #   @return [AssociationSet] Schema's association set (empty by default)
-    option :associations, reader: true, default: -> rel {
-      rel.schema? ? rel.schema.associations : Schema::EMPTY_ASSOCIATION_SET
-    }
-
-    # @!attribute [r] dataset
-    #   @return [Object] dataset used by the relation provided by relation's gateway
-    #   @api public
-    attr_reader :dataset
-
-    # @!attribute [r] schema
-    #   @return [Schema] returns relation schema object (if defined)
-    #   @api public
-    attr_reader :schema
-
-    # Initializes a relation object
+    # Return schema attribute
     #
-    # @param dataset [Object]
+    # @return [Schema::Type]
     #
-    # @param options [Hash]
-    #   @option :mappers [MapperRegistry]
-    #   @option :schema_hash [#[]]
-    #   @option :associations [AssociationSet]
-    #
     # @api public
-    def initialize(dataset, options = EMPTY_HASH)
-      @dataset = dataset
-      @schema = self.class.schema
-      super
+    def [](name)
+      schema[name]
     end
 
     # Yields relation tuples
     #
     # @yield [Hash]
@@ -141,29 +133,52 @@
     #
     # @return [TrueClass, FalseClass]
     #
     # @api private
     def schema?
-      ! schema.nil?
+      ! schema.empty?
     end
 
+    # Return a new relation with provided dataset and additional options
+    #
+    # @param [Object] dataset
+    # @param [Hash] new_opts Additional options
+    #
+    # @api public
+    def new(dataset, new_opts = EMPTY_HASH)
+      self.class.new(dataset, new_opts.empty? ? options : options.merge(new_opts))
+    end
+
     # Returns a new instance with the same dataset but new options
     #
     # @param new_options [Hash]
     #
     # @return [Relation]
     #
     # @api private
     def with(new_options)
-      __new__(dataset, options.merge(new_options))
+      new(dataset, options.merge(new_options))
     end
 
-    private
+    # Return all registered relation schemas
+    #
+    # @return [Hash<Symbol=>Schema>]
+    #
+    # @api public
+    def schemas
+      @schemas ||= self.class.schemas
+    end
 
-    # @api private
-    def __new__(dataset, new_opts = EMPTY_HASH)
-      self.class.new(dataset, options.merge(new_opts))
+    # Return schema's association set (empty by default)
+    #
+    # @return [AssociationSet] Schema's association set (empty by default)
+    #
+    # @api public
+    def associations
+      @associations ||= schema.associations
     end
+
+    private
 
     # @api private
     def composite_class
       Relation::Composite
     end