[core] port processor to use dry-transformer

Author: solnic

core/lib/rom/core.rb

@@ -10,7 +10,7 @@
 require 'rom/schema_plugin'
 require 'rom/relation'
 require 'rom/mapper'
-require 'rom/processor/transproc'
+require 'rom/processor/transformer'
 require 'rom/commands'
 
 # rom Global

core/lib/rom/mapper.rb

@@ -61,7 +61,7 @@ def self.headers(header)
     # @return [Mapper]
     #
     # @api private
-    def self.build(header = self.header, processor = :transproc)
+    def self.build(header = self.header, processor = :transformer)
       new(header, processor)
     end
 
@@ -74,7 +74,7 @@ def self.registry(descendants)
     end
 
     # @api private
-    def initialize(header, processor = :transproc)
+    def initialize(header, processor = :transformer)
       processor = Mapper.processors.fetch(processor)
       @transformers = self.class.headers(header).map do |hdr|
         processor.build(self, hdr)

core/lib/rom/processor/composer.rb

@@ -0,0 +1,37 @@
+# frozen_string_literal: true
+
+module ROM
+  class Processor
+    # @api private
+    module Composer
+      # @api private
+      class Factory
+        attr_reader :fns, :default
+
+        # @api private
+        def initialize(default = nil)
+          @fns = []
+          @default = default
+        end
+
+        # @api private
+        def <<(other)
+          fns.concat(Array(other).compact)
+          self
+        end
+
+        # @api private
+        def to_fn
+          fns.reduce(:+) || default
+        end
+      end
+
+      # @api private
+      def compose(default = nil)
+        factory = Factory.new(default)
+        yield(factory)
+        factory.to_fn
+      end
+    end
+  end
+end

core/lib/rom/processor/transproc.rb renamed to core/lib/rom/processor/transformer.rb

@@ -1,29 +1,31 @@
 # frozen_string_literal: true
 
-require 'transproc/all'
+require 'dry/transformer/all'
 
 require 'rom/processor'
+require 'rom/processor/composer'
 
 module ROM
   class Processor
-    # Data mapping transformer builder using Transproc
+    # Data mapping transformer builder using dry-transformer
     #
-    # This builds a transproc function that is used to map a whole relation
+    # This builds a transformer object that is used to map a whole relation
     #
-    # @see https://github.com/solnic/transproc too
+    # @see https://github.com/dry-rb/dry-transformer
     #
     # @private
-    class Transproc < Processor
-      include ::Transproc::Composer
+    class Transformer < Processor
+      include Composer
 
       module Functions
-        extend ::Transproc::Registry
+        extend Dry::Transformer::Registry
+
+        import Dry::Transformer::Coercions
+        import Dry::Transformer::ArrayTransformations
+        import Dry::Transformer::HashTransformations
+        import Dry::Transformer::ClassTransformations
+        import Dry::Transformer::ProcTransformations
 
-        import ::Transproc::Coercions
-        import ::Transproc::ArrayTransformations
-        import ::Transproc::HashTransformations
-        import ::Transproc::ClassTransformations
-        import ::Transproc::ProcTransformations
         INVALID_INJECT_UNION_VALUE = "%s attribute: block is required for :from with union value.".freeze
 
         def self.identity(tuple)
@@ -73,15 +75,15 @@ def self.inject_union_value(tuple, name, keys, coercer)
       # @api private
       attr_reader :row_proc
 
-      # Build a transproc function from the header
+      # Build a transformer object from the header
       #
       # @param [ROM::Header] header
       #
-      # @return [Transproc::Function]
+      # @return [Dry::Transformer::Pipe]
       #
       # @api private
       def self.build(mapper, header)
-        new(mapper, header).to_transproc
+        new(mapper, header).call
       end
 
       # @api private
@@ -93,12 +95,12 @@ def initialize(mapper, header)
         initialize_row_proc
       end
 
-      # Coerce mapper header to a transproc data mapping function
+      # Coerce mapper header to a transformer object
       #
-      # @return [Transproc::Function]
+      # @return [Dry::Transformer::Pipe]
       #
       # @api private
-      def to_transproc
+      def call
         compose(t(:identity)) do |ops|
           combined = header.combined
           ops << t(:combine, combined.map(&method(:combined_args))) if combined.any?

core/lib/rom/transformer.rb

@@ -1,16 +1,15 @@
 # frozen_string_literal: true
 
 require 'dry/core/class_attributes'
-require 'transproc/transformer'
+require 'dry/transformer'
 
-require 'rom/processor/transproc'
+require 'rom/processor/transformer'
 
 module ROM
-  # Transformer is a data mapper which uses Transproc's transformer DSL to define
-  # transformations.
+  # Transformer is a data mapper which uses `Dry::Transformer`'s DSL to define transformations.
   #
   # @api public
-  class Transformer < Transproc::Transformer[ROM::Processor::Transproc::Functions]
+  class Transformer < Dry::Transformer[Processor::Transformer::Functions]
     extend Dry::Core::ClassAttributes
 
     # @!method self.register_as

core/rom-core.gemspec

@@ -28,7 +28,7 @@ Gem::Specification.new do |gem|
   gem.add_runtime_dependency 'dry-types', '~> 1.0'
   gem.add_runtime_dependency 'dry-struct', '~> 1.0'
   gem.add_runtime_dependency 'dry-initializer', '~> 3.0', '>= 3.0.1'
-  gem.add_runtime_dependency 'transproc', '~> 1.0', '>= 1.1.0'
+  gem.add_runtime_dependency 'dry-transformer', '~> 0.1'
 
   gem.add_development_dependency 'rake', '~> 10.3'
   gem.add_development_dependency 'rspec', '~> 3.5'