Theory ObjectPointer

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section‹Object›
text‹In this theory, we introduce the typed pointer for the class Object. This class is the 
common superclass of our class model.›
theory ObjectPointer
  imports
    Ref
begin

datatype 'object_ptr object_ptr = Ext 'object_ptr
register_default_tvars "'object_ptr object_ptr" 

instantiation object_ptr :: (linorder) linorder
begin
definition less_eq_object_ptr :: "'object_ptr::linorder object_ptr ⇒ 'object_ptr object_ptr ⇒ bool"
  where "less_eq_object_ptr x y ≡ (case x of Ext i ⇒ (case y of Ext j ⇒ i ≤ j))"
definition less_object_ptr :: "'object_ptr::linorder object_ptr ⇒ 'object_ptr object_ptr ⇒ bool"
  where "less_object_ptr x y ≡ x ≤ y ∧ ¬ y ≤ x"
instance by(standard, auto simp add: less_eq_object_ptr_def less_object_ptr_def 
      split: object_ptr.splits)
end

end