'goto" gone from computer languages or is it!

[Lyle Bickley]

On Friday 13 May 2005 13:59, John Hogerhuis wrote:
> On 5/13/05, Dave Dunfield <dave04a at dunfield.com> wrote:
> > Now I disagree with you - if you rely on a particular implementations
> > handling of undefined behaviour, your abstraction is no longer clear
> > or unambiguous - in fact, quite the opposite...
> >
> > The only correction to be made to your original statement, is that
> > the programming language must be used correctly - an idea that I
> > automatically assumed from the beginning, hence I originally had
> > nothing to add to it.
>
> Well yeah, I'll buy that... there's usually no good reason to make
> dependencies on implementation dependent behavior. I'd make exception
> for areas where standards committees don't define something just
> because they can't get squabbling vendors to agree... SQL standard
> comes to mind... last version I looked at (a long time ago) couldn't
> come to a standard 'date' type. Also some languages like Forth have a
> culture of extending the language and room must be made for differing
> implementations of even the same words.
>
> All I was saying is that implementation dependent behavior is real as
> opposed to abstract so you can determine exactly what any given line
> of code will do as opposed to a dodgy/out-of-date specification or
> design document.

In K&R's "THE C PROGRAMMING LANGUAGE", 1978, section 2.12 "Precedence and 
Order of Evaluation" is a discussion of compilers generating different 
answers depending on interpretation (side effects).  The first sentence in 
the final paragraph reads: "The moral of this discussion is that writing code 
which depends on order of evaluation is a bad programming practice in any 
language."

I'll buy that.

Lyle
-- 
Lyle Bickley
Bickley Consulting West Inc.
http://bickleywest.com
"Black holes are where God is dividing by zero"