Re: Ada Versus PL/I - The debate continues

["John W. Kennedy" <jwkenne@attglobal.net>]

Peter Flass wrote:
> "John W. Kennedy" wrote:
>>>Error recovery in Ada works quite well, thank you.

>>Robin believes that it is a _good_ thing that PL/I allows the run-time
>>ON statement to alter the currently-assigned error recovery, and that
>>PL/I allows return to point of error, and will not be convinced that
>>both of these were excluded from Ada (and every other language I know of
>>with error handling) precisely because experience with PL/I was unfortunate.

> I disagree vehemently.  They were excluded because they were difficult
> to implement.

If you want to accuse the authors of the "Ada '83 Rationale" of lying, 
do it to their faces and leave me out of it.

> Java
> (I believe) with its "try/catch" has effectively tried to re-introduce
> this.  Any other type of error handling is deficient.

Java's try/catch is (as far as this goes) no different from C++'s 
try/catch.  Exception handlers are based on the call stack, with no 
ability to arbitrarily switch from one handler to another at run time, 
and at least one block (the "try" block) must be terminated.  Java's 
only significant addition is the optional "finally" block (a block that 
is executed -- normally resource-release code -- after either successful 
or unsuccessful execution).

-- 
John W. Kennedy
"Only an idiot fights a war on two fronts.  Only
the heir to the throne of the kingdom of idiots
would fight a war on twelve fronts."
   -- "Babylon 5"