“Constants are widely known for the detestable practice of changing their values; we should prepare ourselves against the consequences of such fickleness”

Perfect reusable components are not obtained at the first shot.

C++ is the only current language making COBOL look good

Ask not first what the system does; ask what it does it to!

Careful as they may be, developers of Eiffel libraries will always run into cases in which, after releasing a library class, they suddenly experience what in French is called esprit de l’escalier or wit of the staircase: a great thought which unfortunately is an afterthought.

Software entities (classes, modules, functions, etc.) should be open for extension, but closed for modification.

As Mr. Nagle so competently points out, almost no one uses Eiffel; in fact until recently there were only 9 users. But now a 10th person just started, so we are holding a conference, appropriately titled the TENTH Eiffel USER conference, to celebrate.

The role of a trainer or consultant is to empower the customer, not to make himself indispensable

I have always felt sympathy towards the biologists who accept to debate creationists. Now I also understand them better; one can fight opinions, not articles of faith.

Eiffel borrows quite openly from several earlier programming languages and I am sure that if we had found a good language construct in C we would have used it as well.

I think Smalltalk is inappropriate for serious industrial developments. After all, run time is a little late to find out whether you have a landing gear.

Incorrect documentation is often worse than no documentation.

Writing a class without its contract would be similar to producing an engineering component (electrical circuit, VLSI (Very Large Scale Integration) chip, bridge, engine…) without a spec. No professional engineer would even consider the idea.

Correctness is clearly the prime quality. If a system does not do what it is supposed to do, then everything else about it matters little.

Like a clever reply that would have stunned all the other dinner guests – if only you had thought of it before walking down the stairs after the party is over

When a man sees something desirable, he must reflect on the fact that with time it could come to involve what is detestable. When he sees something that is beneficial, he should reflect that sooner or later it, too, could come to involve harm.

Fascism does not want them, forbids them, and that’s why you’re not a Fascist; it wants everybody to be the same, and you are not. But immaculate virtue does not exist either, or if it exists it is detestable.