'goto" gone from computer languages or is it!

[John Hogerhuis]

On 5/12/05, Antonio Carlini <a.carlini at ntlworld.com> wrote:
> John Hogerhuis wrote:
> 
> > All computer scientists have ever proved is that you could get
> > by without goto. They jumped to an unwarranted conclusion when
> > they decided it should never be used.
> 
> One of Dijkstra's interests was formal specification and verification:
> basically unambigously describing what you want to do and then proving
> afterwards that you've done it. You'll notice that the bit in the
> middle doesn't get a look in :-) In fact, you could argue that the
> bit in the middle needs to be constrained just so the proof is a
> practical proposition.
> 

Yeah there can be no algorithm to test algorithm correctness. Halting
problem... so naturally you would have to restrict yourself to
something less than a turing machine to get this.

> So it's nothing to do with stifling your creativity: be as
> creative as you like. It's just unlikely that any of us
> (including you) will ever know whether your prorams (or at
> least any of them of significant size) are correct or not.
> 

Agreed, but nor should anyone really care about provable correctness,
right? Engineering is about making things that are practically useful,
i.e. "good enough"-- we're not designing stained glass windows for the
Church of Reason, we're simply making and maintaining tools to solve
todays problems more efficiently than if those tools were not
available.

-- John.