Eric Lippert from the C# design team has an interesting article on the ten 
worst features of C#. At least eight of these have been solved in Ada. Did 
Jean I. time-travel into the future and learned from the C# mistakes, when 
designing Ada?

Lean back and enjoy!

http://www.informit.com/articles/article.aspx?p=2425867


BTW, the two issues that are, to some degree, applicable to Ada are

#9 Comparison operators for your own arithmetic (e.g., for your own 
rational numbers).

In Ada, the "/="-operator is automatically the negation of "=". Which is 
great. But given "=", "<", and ">", why does one have to implement "<=" 
and ">=", as well. (Five Operators, where three would suffice.) (*)

The situation with C# is even worse. You need to define/override at least 
nine methods.

#2 Finaliz(ers) are fragile

In Ada, the finalize procedure for an object can be called more than once, 
Finalize should rather not raise an exception, ... apparently, C# 
finalzisers suffer from similar problems: "any time a finalizer runs, you 
could argue that the program either has a bug or is in a dangerous state, 
such as being shut down unexpectedly via a thread abort".

The remaining eight C# issues have been solved in Ada.



-------

(*) One might argue that two operators, e.g., "=" and "<" would suffice, 
rather than three. If neither A=B nor A<B, then A>B is obvious, isn't it?

But not all sorts of "arithmetic", where you want to take comparisons, 
have the property that either of A=B, A>B, A<B is true:

    -- Arithmetic with "special values", such as "Not a Number" for
       floating point operations. If A is NaN, then neither A=B nor A>B
       nor A<B would hold, even if B is also NaN.

    -- Another example would be sets: A<B would indicate "A is a proper
       subset of B. If, e.g., A={1} and B={2,3}, then neither A=B nor
       A<B nor A>B.

On the other hand, A <= B should never mean anything different from

   (A < B) or (A = B)!

Similarly for A >= B.

--------  I  love  the  taste  of  Cryptanalysis  in  the morning!  --------
www.uni-weimar.de/de/medien/professuren/mediensicherheit/people/stefan-lucks
----Stefan.Lucks (at) uni-weimar.de, Bauhaus-Universität Weimar, Germany----