Add to_iruby_mimebundle support

Author: mrkn

lib/iruby/display.rb

@@ -30,7 +30,7 @@ def display(obj, options = {})
         render(data, obj, exact_mime, fuzzy_mime)
 
         # IPython always requires a text representation
-        render(data, obj, 'text/plain', nil) unless data['text/plain']
+        render_by_registry(data, obj, 'text/plain', nil) unless data['text/plain']
 
         # As a last resort, interpret string representation of the object
         # as the given mime type.
@@ -68,6 +68,32 @@ def ascii?(mime)
       end
 
       def render(data, obj, exact_mime, fuzzy_mime)
+        # First examine to_iruby_mimebundle
+
+        if obj.respond_to?(:to_iruby_mimebundle)
+          # If the object can respond to to_iruby_mimebundle,
+          # IRuby uses it and ignores all the registered renderer.
+          kwargs = {}
+          include_mime = [exact_mime, fuzzy_mime].compact
+          kwargs[:include] = include_mime unless include_mime.empty?
+          # TODO: support `exclude:` keyword argument to specify mime types to be excluded
+
+          # TODO: should handle metadata correctly
+          formats, metadata = obj.to_iruby_mimebundle(**kwargs)
+
+          # formats should be a Hash that maps mime-type string to
+          # the redered data.
+          formats.each do |mime, value|
+            data[mime] = value unless value.nil?
+          end
+        end
+
+        unless data.key?(exact_mime)
+          render_by_registry(data, obj, exact_mime, fuzzy_mime)
+        end
+      end
+
+      private def render_by_registry(data, obj, exact_mime, fuzzy_mime)
         # Filter matching renderer by object type
         renderer = Registry.renderer.select { |r| r.match?(obj) }
 

test/iruby/display_test.rb

@@ -0,0 +1,188 @@
+module IRubyTest
+  class DisplayTest < TestBase
+    def setup
+      @object = Object.new
+      @object.instance_variable_set(:@to_html_called, false)
+      @object.instance_variable_set(:@to_markdown_called, false)
+      @object.instance_variable_set(:@to_iruby_called, false)
+      @object.instance_variable_set(:@to_iruby_mimebundle_called, false)
+
+      class << @object
+        attr_reader :to_html_called
+        attr_reader :to_markdown_called
+        attr_reader :to_iruby_called
+        attr_reader :to_iruby_mimebundle_called
+
+        def html
+          "<b>html</b>"
+        end
+
+        def markdown
+          "*markdown*"
+        end
+
+        def inspect
+          "!!! inspect !!!"
+        end
+      end
+    end
+
+    def define_to_html
+      class << @object
+        def to_html
+          @to_html_called = true
+          html
+        end
+      end
+    end
+
+    def define_to_markdown
+      class << @object
+        def to_markdown
+          @to_markdown_called = true
+          markdown
+        end
+      end
+    end
+
+    def define_to_iruby
+      class << @object
+        def to_iruby
+          @to_iruby_called = true
+          ["text/html", "<b>to_iruby</b>"]
+        end
+      end
+    end
+
+    def define_to_iruby_mimebundle
+      class << @object
+        def to_iruby_mimebundle(include: [])
+          @to_iruby_mimebundle_called = true
+          mimes = if include.empty?
+                    ["text/html", "text/markdown", "application/json"]
+                  else
+                    include
+                  end
+          formats = mimes.map { |mime|
+            result = case mime
+                     when "text/html"
+                       "<i>html</i>"
+                     when "text/markdown"
+                       "**markdown**"
+                     when "application/json"
+                       %Q[{"mimebundle": "json"}]
+                     end
+            [mime, result]
+          }.to_h
+          metadata = {}
+          return formats, metadata
+        end
+      end
+    end
+
+    def assert_iruby_display(expected)
+      assert_equal(expected,
+                   {
+                     result: IRuby::Display.display(@object),
+                     to_html_called: @object.to_html_called,
+                     to_markdown_called: @object.to_markdown_called,
+                     to_iruby_called: @object.to_iruby_called,
+                     to_iruby_mimebundle_called: @object.to_iruby_mimebundle_called
+                   })
+    end
+
+    sub_test_case("the object cannot handle all the mime types") do
+      def test_display
+        assert_iruby_display({
+                               result: {"text/plain" => "!!! inspect !!!"},
+                               to_html_called: false,
+                               to_markdown_called: false,
+                               to_iruby_called: false,
+                               to_iruby_mimebundle_called: false
+                             })
+      end
+    end
+
+    sub_test_case("the object can respond to to_iruby") do
+      def setup
+        super
+        define_to_iruby
+      end
+
+      def test_display
+        assert_iruby_display({
+                               result: {
+                                 "text/html" => "<b>to_iruby</b>",
+                                 "text/plain" => "!!! inspect !!!"
+                               },
+                               to_html_called: false,
+                               to_markdown_called: false,
+                               to_iruby_called: true,
+                               to_iruby_mimebundle_called: false
+                             })
+      end
+
+      sub_test_case("the object can respond to to_markdown") do
+        def setup
+          super
+          define_to_markdown
+        end
+
+        def test_display
+          assert_iruby_display({
+                                 result: {
+                                   "text/html" => "<b>to_iruby</b>",
+                                   "text/plain" => "!!! inspect !!!"
+                                 },
+                                 to_html_called: false,
+                                 to_markdown_called: false,
+                                 to_iruby_called: true,
+                                 to_iruby_mimebundle_called: false
+                               })
+        end
+      end
+
+      sub_test_case("the object can respond to to_html") do
+        def setup
+          super
+          define_to_html
+        end
+
+        def test_display
+          assert_iruby_display({
+                                 result: {
+                                   "text/html" => "<b>html</b>",
+                                   "text/plain" => "!!! inspect !!!"
+                                 },
+                                 to_html_called: true,
+                                 to_markdown_called: false,
+                                 to_iruby_called: false,
+                                 to_iruby_mimebundle_called: false
+                               })
+        end
+
+        sub_test_case("the object can respond to to_iruby_mimebundle") do
+          def setup
+            super
+            define_to_iruby_mimebundle
+          end
+
+          def test_display
+            assert_iruby_display({
+                                   result: {
+                                     "text/html" => "<b>html</b>",
+                                     "text/markdown" => "**markdown**",
+                                     "application/json" => %Q[{"mimebundle": "json"}],
+                                     "text/plain" => "!!! inspect !!!"
+                                   },
+                                   to_html_called: true,
+                                   to_markdown_called: false,
+                                   to_iruby_called: false,
+                                   to_iruby_mimebundle_called: true
+                                 })
+          end
+        end
+      end
+    end
+  end
+end