"Object-Oriented Software Construction" uses Eiffel which is an excellent OO language especially for explaining certain OO related concepts. Preconditions, post

"Object-Oriented Software Construction" uses Eiffel which is an excellent OO language especially for explaining certain OO related concepts. Preconditions, postconditions, invariants (design by contract) etc. That's why I'd be quite interested in a comparison because Smalltalk is another excellent OO language (arguably the best for explaining concepts etc. but I'd say Eiffel is close enough)