From 3db77076146440719056b2fac262d9529b7c875f Mon Sep 17 00:00:00 2001
From: Torsten Ruger <torsten@villataika.fi>
Date: Sat, 16 Feb 2019 23:24:16 +0200
Subject: [PATCH] Get a basic MetaClass going

Does get created in new, but not in boot.
Also not yet used in compiling
---
 lib/parfait.rb                              |   1 +
 lib/parfait/behaviour.rb                    |   2 +-
 lib/parfait/class.rb                        |   6 +-
 lib/parfait/meta_class.rb                   | 107 ++++++++++++++++++++
 lib/risc/parfait_boot.rb                    |   3 +-
 test/parfait/test_meta_class.rb             |  50 +++++++++
 test/parfait/test_space.rb                  |   2 +-
 test/risc/interpreter/calling/test_minus.rb |   2 +-
 test/risc/test_interpreter.rb               |   4 +-
 test/risc/test_linker.rb                    |   2 +-
 test/vool/blocks/test_class_blocks.rb       |   6 +-
 11 files changed, 175 insertions(+), 10 deletions(-)
 create mode 100644 lib/parfait/meta_class.rb
 create mode 100644 test/parfait/test_meta_class.rb

diff --git a/lib/parfait.rb b/lib/parfait.rb
index c7abe770..35ab3f39 100644
--- a/lib/parfait.rb
+++ b/lib/parfait.rb
@@ -30,6 +30,7 @@ require_relative "parfait/data_object"
 require_relative "parfait/integer"
 require_relative "parfait/behaviour"
 require_relative "parfait/class"
+require_relative "parfait/meta_class"
 require_relative "parfait/list"
 require_relative "parfait/word"
 require_relative "parfait/binary_code"
diff --git a/lib/parfait/behaviour.rb b/lib/parfait/behaviour.rb
index 4f979a0d..183b4f0e 100644
--- a/lib/parfait/behaviour.rb
+++ b/lib/parfait/behaviour.rb
@@ -45,7 +45,7 @@ module Parfait
       raise "resolve_method #{m_name}.#{m_name.class}" unless m_name.is_a?(Symbol)
       method = get_instance_method(m_name)
       return method if method
-      if( super_class_name != :Object )
+      if( super_class_name && super_class_name != :Object )
         method = self.super_class.resolve_method(m_name)
       end
       method
diff --git a/lib/parfait/class.rb b/lib/parfait/class.rb
index 8a76c8e1..45e8da89 100644
--- a/lib/parfait/class.rb
+++ b/lib/parfait/class.rb
@@ -18,10 +18,11 @@ module Parfait
   class Class < Object
     include Behaviour
 
-    attr :type, :instance_type , :name , :instance_methods , :super_class_name
+    attr :type, :instance_type , :name , :instance_methods
+    attr :super_class_name , :meta_class
 
     def self.type_length
-      5
+      6
     end
 
     def initialize( name , superclass , instance_type)
@@ -30,6 +31,7 @@ module Parfait
       self.super_class_name = superclass
       self.instance_methods = List.new
       set_instance_type( instance_type )
+      self.meta_class = MetaClass.new( self )
     end
 
     def rxf_reference_name
diff --git a/lib/parfait/meta_class.rb b/lib/parfait/meta_class.rb
new file mode 100644
index 00000000..f2948855
--- /dev/null
+++ b/lib/parfait/meta_class.rb
@@ -0,0 +1,107 @@
+#
+# In many respects a MetaClass is like a Class. We haven't gone to the full ruby/oo level
+# yet, where the metaclass is actually a class instance, but someday.
+
+# A Class in general can be viewed as a way to generate methods for a group of objects.
+
+# A MetaClass serves the same function, but just for one object, the class object that
+# is the meta_class of.
+# This is slightnly different in the way that the type of the class must actually
+# change, whereas for a class the instance type changes and only objects generated
+# henceafter have a different type.
+
+# This is still a first version, this change is not implemeted, also classes at boot don't
+# have metaclasses yet, so still a bit TODO
+
+# Another current difference is that a metaclass has no superclass. Also no name.
+# There is a one to one relationship between a class instance and it's meta_class instance.
+
+module Parfait
+  class MetaClass < Object
+    include Behaviour
+
+    attr :type, :instance_type , :instance_methods , :clazz
+
+    def self.type_length
+      4
+    end
+
+    def initialize( clazz )
+      super()
+      self.clazz = clazz
+      self.instance_methods = List.new
+      set_instance_type( clazz.get_type() )
+    end
+
+    def rxf_reference_name
+      clazz.name
+    end
+
+    def inspect
+      "MetaClass(#{clazz.name})"
+    end
+
+    # no superclass, return nil to signal
+    def super_class_name
+      nil
+    end
+
+    def add_method_for(name , type , frame , body )
+      method = Parfait::VoolMethod.new(name , type , frame , body )
+      add_method( method )
+      method
+    end
+
+    def add_method(method)
+      raise "Must be untyped method #{method}" unless method.is_a? Parfait::VoolMethod
+      instance_methods.push(method)
+    end
+
+    def get_method(name)
+      instance_methods.find{|m| m.name == name }
+    end
+
+    # adding an instance changes the instance_type to include that variable
+    def add_instance_variable( name , type)
+      self.instance_type = instance_type.add_instance_variable( name , type )
+    end
+
+    # setting the type generates all methods for this type
+    # (or will do, once we store the methods code to do that)
+    def set_instance_type( type )
+      raise "type must be type #{type}" unless type.is_a?(Type)
+      self.instance_type = type
+    end
+
+    # return the super class, but raise exception if either the super class name
+    # or the super classs is nil.
+    # Use only for non Object base class
+    def super_class!
+      raise "No super_class for class #{name}" unless super_class_name
+      s = super_class
+      raise "superclass not found for class #{name} (#{super_class_name})" unless s
+      s
+    end
+
+    # return the super class
+    # we only store the name, and so have to resolve.
+    # Nil name means no superclass, and so nil is a valid return value
+    def super_class
+      return nil unless super_class_name
+      Parfait.object_space.get_class_by_name(super_class_name)
+    end
+
+    # ruby 2.1 list (just for reference, keep at bottom)
+    #:allocate, :new, :superclass
+
+    # + modules
+    # :<, :<=, :>, :>=, :included_modules, :include?, :name, :ancestors, :instance_methods, :public_instance_methods,
+    # :protected_instance_methods, :private_instance_methods, :constants, :const_get, :const_set, :const_defined?,
+    # :const_missing, :class_variables, :remove_class_variable, :class_variable_get, :class_variable_set,
+    # :class_variable_defined?, :public_constant, :private_constant, :singleton_class?, :include, :prepend,
+    # :module_exec, :class_exec, :module_eval, :class_eval, :method_defined?, :public_method_defined?,
+    # :private_method_defined?, :protected_method_defined?, :public_class_method, :private_class_method, :autoload,
+    # :autoload?, :instance_method, :public_instance_method
+
+  end
+end
diff --git a/lib/risc/parfait_boot.rb b/lib/risc/parfait_boot.rb
index 2511edaf..71e9d7d9 100644
--- a/lib/risc/parfait_boot.rb
+++ b/lib/risc/parfait_boot.rb
@@ -146,7 +146,7 @@ module Parfait
                        arguments_type: :Type , self_type: :Type, frame_type: :Type ,
                        name: :Word , blocks: :Block} ,
       Class: {instance_methods: :List, instance_type: :Type,
-              name: :Word, super_class_name: :Word },
+              name: :Word, super_class_name: :Word , meta_class: :MetaClass},
       DataObject: {},
       Data4: {},
       Data8: {},
@@ -158,6 +158,7 @@ module Parfait
       Message: { next_message: :Message,   receiver: :Object, frame: :NamedList ,
                  return_address: :Integer, return_value: :Object,
                  caller: :Message , method: :TypedMethod ,     arguments: :NamedList },
+      MetaClass: {instance_methods: :List, instance_type: :Type, clazz: :Class },
       NamedList: {},
       NilClass: {},
       Object: {},
diff --git a/test/parfait/test_meta_class.rb b/test/parfait/test_meta_class.rb
new file mode 100644
index 00000000..3a284194
--- /dev/null
+++ b/test/parfait/test_meta_class.rb
@@ -0,0 +1,50 @@
+require_relative "helper"
+
+module Parfait
+  class TestMetaClass < ParfaitTest
+
+    def setup
+      super
+      @try = @space.create_class( :Try , :Object).meta_class
+    end
+
+    def test_type_forclass
+      assert_equal "Class(Space)" ,  @space.get_type.object_class.inspect
+      assert_equal :Space ,          @space.get_type.object_class.name
+    end
+    def test_new_superclass_name
+      assert_equal :Object , @try.clazz.super_class_name
+    end
+    def test_new_superclass
+      assert_equal "Class(Try)" , @try.clazz.inspect
+      assert_equal "MetaClass(Try)" , @try.inspect
+    end
+    def test_new_methods
+      assert_equal @try.method_names.class, @try.instance_methods.class
+      assert_equal @try.method_names.get_length , @try.instance_methods.get_length
+    end
+    def test_remove_nothere
+      assert  !@try.remove_instance_method(:foo)
+    end
+    def test_resolve
+      assert_nil @try.resolve_method :foo
+    end
+    def test_remove_method
+      assert_equal false , @try.remove_instance_method( :foo)
+    end
+    def test_add_nil_method_raises
+      assert_raises{ @try.add_instance_method(nil)}
+    end
+    def test_add_instance_variable_changes_type
+      before = @space.get_class.instance_type
+      @space.get_class.add_instance_variable(:counter , :Integer)
+      assert before != @space.get_class.instance_type
+    end
+    def test_add_instance_variable_changes_type_hash
+      before = @space.get_class.instance_type.hash
+      @space.get_class.add_instance_variable(:counter , :Integer)
+      assert before != @space.get_class.instance_type.hash
+    end
+
+  end
+end
diff --git a/test/parfait/test_space.rb b/test/parfait/test_space.rb
index 249194d3..375f5709 100644
--- a/test/parfait/test_space.rb
+++ b/test/parfait/test_space.rb
@@ -6,7 +6,7 @@ module Parfait
     def classes
       [:BinaryCode,:Block,:CacheEntry,:Callable,:CallableMethod,:Class,
         :DataObject,:Data4,:Data8,:Data16,:Dictionary,:Factory, :Integer,:FalseClass,
-        :List,:Message,:NamedList,:NilClass,:Object,:ReturnAddress,
+        :List,:Message, :MetaClass, :NamedList,:NilClass,:Object,:ReturnAddress,
         :Space,:TrueClass,:Type,:VoolMethod,:Word]
     end
 
diff --git a/test/risc/interpreter/calling/test_minus.rb b/test/risc/interpreter/calling/test_minus.rb
index eac087e5..d1f419ea 100644
--- a/test/risc/interpreter/calling/test_minus.rb
+++ b/test/risc/interpreter/calling/test_minus.rb
@@ -41,7 +41,7 @@ module Risc
       ret = main_ticks(68)
       assert_equal FunctionReturn ,  ret.class
       assert_equal :r1 ,  ret.register.symbol
-      assert_equal 22284 ,  @interpreter.get_register(ret.register)
+      assert_equal 24204 ,  @interpreter.get_register(ret.register)
     end
   end
 end
diff --git a/test/risc/test_interpreter.rb b/test/risc/test_interpreter.rb
index 89077d93..8e77f8c2 100644
--- a/test/risc/test_interpreter.rb
+++ b/test/risc/test_interpreter.rb
@@ -54,7 +54,7 @@ module Risc
     end
     def test_pc1
       @interpreter.tick
-      assert_equal 21688 , @interpreter.pc
+      assert_equal 23672 , @interpreter.pc
     end
     def test_tick2
       @interpreter.tick
@@ -68,7 +68,7 @@ module Risc
     def test_pc2
       @interpreter.tick
       @interpreter.tick
-      assert_equal 21692 , @interpreter.pc
+      assert_equal 23676 , @interpreter.pc
     end
     def test_tick_14_jump
       14.times {@interpreter.tick}
diff --git a/test/risc/test_linker.rb b/test/risc/test_linker.rb
index 03917738..fb506201 100644
--- a/test/risc/test_linker.rb
+++ b/test/risc/test_linker.rb
@@ -25,7 +25,7 @@ module Risc
       assert_equal 0 ,  Position.get(@linker.cpu_init).at
     end
     def test_cpu_at
-      assert_equal "0x4f1c" ,  Position.get(@linker.cpu_init.first).to_s
+      assert_equal "0x569c" ,  Position.get(@linker.cpu_init.first).to_s
     end
     def test_cpu_label
       assert_equal Position ,  Position.get(@linker.cpu_init.first).class
diff --git a/test/vool/blocks/test_class_blocks.rb b/test/vool/blocks/test_class_blocks.rb
index b90e762b..3dd436e1 100644
--- a/test/vool/blocks/test_class_blocks.rb
+++ b/test/vool/blocks/test_class_blocks.rb
@@ -16,8 +16,12 @@ module VoolBlocks
       begin
         vool.to_mom(nil)
       rescue => err
-        assert err.message.include?("Blocks")
+        assert err.message.include?("Blocks") , err.message
       end
     end
+    def test_assign_compiles
+      vool = Ruby::RubyCompiler.compile( as_class_method("val = 0") ).to_vool
+      assert_equal Mom::MomCompiler , vool.to_mom(nil).class
+    end
   end
 end