From 48e18ac9cd3d4985504746983bb5a358e3b639a7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Torsten=20R=C3=BCger?= <torsten@rubydesign.fi>
Date: Tue, 1 Oct 2019 20:55:05 +0300
Subject: [PATCH] the superclass of a singleton class is the singleton class of
 the superclass

And i have tests to prove it!
That just rolls of the tongue, it had to be the commit message
---
 lib/parfait/behaviour.rb                          |  1 +
 lib/parfait/singleton_class.rb                    | 11 +++++++----
 lib/vool/send_statement.rb                        |  1 +
 test/parfait/test_singleton_class.rb              |  6 ++++++
 test/vool/class_send/test_class_send_inherited.rb |  9 ++++-----
 5 files changed, 19 insertions(+), 9 deletions(-)

diff --git a/lib/parfait/behaviour.rb b/lib/parfait/behaviour.rb
index 03cdd18b..eec3cef2 100644
--- a/lib/parfait/behaviour.rb
+++ b/lib/parfait/behaviour.rb
@@ -80,6 +80,7 @@ module Parfait
         tm = @instance_type.method_names
         raise "resolve_method #{name}.#{m_name} has #{tm}:#{method_names}"
       end
+      #puts "resolve #{m_name}:#{super_class}:"
       return nil unless( s_class = super_class )
       s_class.resolve_method(m_name)
     end
diff --git a/lib/parfait/singleton_class.rb b/lib/parfait/singleton_class.rb
index e0646a25..8f3e6bb2 100644
--- a/lib/parfait/singleton_class.rb
+++ b/lib/parfait/singleton_class.rb
@@ -54,14 +54,17 @@ module Parfait
       @clazz.set_type(@instance_type)
     end
 
-    # Nil name means no superclass, and so nil returned
+    # the super class of a singleton classs is  the singleton class of the super class.
+    # In effect the single classes shadow the class tree, leading to the fact that
+    # a class method defined in a super_class is accessible to a derived class in
+    # much the same way as normal methods are accessible in (normal) derived classes.
     def super_class
-      return nil
+      @clazz.super_class.single_class if @clazz.super_class
     end
 
-    # no superclass, return nil to signal
+    # return the name of the superclass (see there)
     def super_class_name
-      nil
+      super_class.name if @clazz.super_class
     end
 
   end
diff --git a/lib/vool/send_statement.rb b/lib/vool/send_statement.rb
index 86acc055..d31bf9b8 100644
--- a/lib/vool/send_statement.rb
+++ b/lib/vool/send_statement.rb
@@ -44,6 +44,7 @@ module Vool
       @receiver = SelfExpression.new(compiler.receiver_type) if @receiver.is_a?(SelfExpression)
       if(@receiver.ct_type)
         method = @receiver.ct_type.get_method(@name)
+        #puts "Known #{@receiver.ct_type}: method #{method}"
         method = create_method_from_source(compiler) unless( method )
         return simple_call(compiler, method) if method
       end
diff --git a/test/parfait/test_singleton_class.rb b/test/parfait/test_singleton_class.rb
index 1332099e..6bc0a3ff 100644
--- a/test/parfait/test_singleton_class.rb
+++ b/test/parfait/test_singleton_class.rb
@@ -55,5 +55,11 @@ module Parfait
     def test_type_is_single
       assert_equal true , @try.instance_type.is_single?
     end
+    def test_super_class
+      assert_equal SingletonClass , @try.super_class.class
+    end
+    def test_super_class_name
+      assert_equal :"Object.Single" , @try.super_class_name
+    end
   end
 end
diff --git a/test/vool/class_send/test_class_send_inherited.rb b/test/vool/class_send/test_class_send_inherited.rb
index 50d133a9..a048e185 100644
--- a/test/vool/class_send/test_class_send_inherited.rb
+++ b/test/vool/class_send/test_class_send_inherited.rb
@@ -7,12 +7,12 @@ module Vool
 
     def class_main
       <<-eos
-        class Space
+        class Object
           def self.one_plus()
-            return 1 + 1
+            return 1
           end
         end
-        class Space
+        class Space < Object
           def main(arg)
             return Space.one_plus
           end
@@ -21,8 +21,7 @@ module Vool
     end
 
     def setup
-      source = "class Integer < Data4;def +(other);X.int_operator(:+);end;end;" + class_main
-      ret = RubyX::RubyXCompiler.new(RubyX.default_test_options).ruby_to_mom(source)
+      ret = RubyX::RubyXCompiler.new(RubyX.default_test_options).ruby_to_mom(class_main)
       @ins = ret.compilers.find_compiler_name(:main).mom_instructions.next
     end
     def test_array