Re: Building blocks (Was: Design By Contract)

[eachus@spectre.mitre.org (Robert I. Eachus)]

In article <34467890.243549EE@munich.netsurf.de> Joachim Durchholz <joachim.durchholz@munich.netsurf.de> writes:

  > Fie, what's this! Exceptions used for flow control...

   No, a code fragment where errors are explicitly handled.  If you
examine the code more closely you will notice that the inner loop has
an exit statement associated with accepting valid input.  You go
around that loop again if you have bad input.  ONE of the ways to end
up rerunning the input loop is if you handle an exception, there are
usually several others.  This is a common idiom.

   Now in Ada, it may be right to avoid using exceptions for flow
control, but that doesn't mean you should throw the exceptions on the
floor or ignore them.  And once you handle the error, of course you
want to return to the proper state.  So any well implemented state
machine in Ada will have exception handlers, and even gotos in some of
them.  But it doesn't mean that that path is expected to be taken
outside of testing.




--

					Robert I. Eachus

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