move kernel to core and apply the classmethod pattern to all core classes

lib/core/integer.rb

@@ -1,4 +1,7 @@
 module Core
-  module Integer
+  class Integer
+    module ClassMethods
+    end
+    extend ClassMethods    
   end
 end

lib/core/kernel.rb

@@ -0,0 +1,29 @@
+module Core
+  class Kernel
+    
+    #there are no Kernel instances, only class methods.
+    # We use this module syntax to avoid the (ugly) self.
+    module ClassMethods
+      def main_start
+        #TODO extract args into array of strings
+        Vm::Machine.instance.main_start
+      end
+      def main_exit
+        # Machine.exit mov r7 , 0  + swi 0 
+        Vm::Machine.instance.main_exit
+      end
+      def function_entry f_name
+        Vm::Machine.instance.function_entry f_name
+      end
+      def function_exit f_name
+        Vm::Machine.instance.function_exit f_name
+      end
+      def self.puts string
+        # should unwrap from string to char*
+        Vm::Machine.instance.puts string
+      end
+    end
+    
+    extend ClassMethods
+  end
+end

lib/core/string.rb

@@ -1,4 +1,7 @@
 module Core
-  module String
+  class String
+    module ClassMethods
+    end
+    extend ClassMethods    
   end
 end

lib/core/system.rb

@@ -1,9 +1,10 @@
 module Core
   module System
-
-    def puts io , c-string , length 
+    module ClassMethods
+      def puts io , c-string , length 
       
+      end
     end
-    
+    extend ClassMethods    
   end
 end