Eiffel -- a language with assertions

B


  • bottom-up development -- class design
  • contracts -- specify client/server relationships

Design principles -- correctness
  • static typing -- type secure
  • multiple inheritance -- polymorphism
  • dynamic binding -- refinement
  • generic classes -- abstraction
slide: The language Eiffel

The language Eiffel -- keywords
slide: Eiffel -- terminology

Type expressions -- conformance
  • basic types -- Boolean, Integer
  • formal parameter types -- Array[T], List[T]
  • class types -- user-defined
  • anchored types -- like current

Value expressions
  • arithmetic, comparison, method evaluation -- o.m(...)

Assignment
  • var := expression
slide: Eiffel -- type expressions

Control -- method refinement
slide: Eiffel -- control
 


    class  counter  export  inc val  feature 
   count : Integer
   create  is do  count := 0  end 
   inc( n : Integer )  is 
  	 require  n > 0  do 
  	count := count + n
  	 ensure  count =  old  count + n
  	 end 
   val : Integer  is do   Result  := count  end 
    invariant  count >= 0
    end  -- class counter
slide: Eiffel -- objects

Multiple inheritance

 

  class Fixed_List[T] export ...
  inherit
  	List[T]
  	Array[T]
  feature
   ...
  end
slide: Eiffel -- inheritance

Rename and/or redefine

 

  class C export ... inherit
    A rename   m   as m1 redefine p
    B rename   m   as m2 redefine q
  feature
  ...
  end
slide: Eiffel -- techniques

The language Eiffel

B


slide: Eiffel -- summary