Re: Modular Protection vs Assertions ...

On 29 Jul., 15:08, Colin LeMahieu <clemah...@[EMAIL PROTECTED]
> wrote:
> Exceptions are used to handle cases where the failure result could not
> have been predicted beforehand.  A network communications failure
> cannot be tested for and you can only observe its occurrence once it
> has happened.

But a network error it is so often that you shouldn't use exceptions
here either. Don't use exceptions as another control flow (except if
you have serious reasons to do so).

> Contracts are used to reduce the domain and range of a function in to
> terms valid for that function.  A range constraint on the function
> is_even(source: INTEGER) would be result implies source \\ 2 = 0.  A

Sorry this is a result constraint and not a rande constraint.

But the main sentence in your posting is correct:

> Contracts should be fleshed out in debugging and testing.  Exceptions
> can occur during normal program execution and should be anticipated
> and able to recover but only used to recover from things that could
> not have been tested beforehand.