Re: Exception_Occurence and language designers

["Jeffrey R. Carter" <spam.jrcarter.not@spam.not.acm.org>]

Exceptions are subject to Ada's visibility rules. In Ada 83, you could have

with Text_IO;
procedure Foobar is
    procedure Foo is
       Bar : exception;
    begin -- Foo
       raise Bar;
    end Foo;
begin -- Foobar
    Foo;
exception -- Foobar
when others => -- Bar is not visible here
    Text_IO.Put_Line (Item => "An exception occurred");
end Foobar;

Even though Bar is not visible outside Foo, it can still propagate out to Foobar 
and be handled by an others handler. It was impossible from that handler to know 
what has been handled.

Ada.Exceptions is a way to get around these limitations with minimum impact on 
backwards compatibility.

-- 
Jeff Carter
"I would never want to belong to any club that
would have someone like me for a member."
Annie Hall
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