Why don't other programming languages have ranges?

[Bruno Medeiros]

On 29/07/2010 19:49, Walter Bright wrote:
> Don wrote:
>> I agree with Walter's statement that ALL of the components are
>> unreliable, and I think it's important to realize that proofs are the
>> same. Even in the case where the program perfectly implements the
>> algorithm, there can be bugs in the proof.
>
> Also, the hardware running the correct program can fail.

Yes, but that's a different issue. It would still be of value to know 
that the program is correct. For example, you could make a reliable 
system by having several different hardware run the same program and 
compare the results. This is similar to what you said before about 
achieving redundancy, but here you would not need other separate teams 
to write a different programs to compute the same thing, which obviously 
would be a great saving in effort.

I'm not going to argue if it is possible, or practical, or whatever to 
know for sure that your program is correct. My point is just that 
knowing with absolute certainty that a program is correct, that would 
still be quite valuable, regardless of the fact that hardware, or other 
programs, systems, etc., could fail.


-- 
Bruno Medeiros - Software Engineer