Re: No Go To's Forever!

[Keith Thompson <kst@cts.com>]

"Ken Garlington" <Ken.Garlington@computer.org> writes:
> "Robert Dewar" <robert_dewar@my-deja.com> wrote in message
> news:8b93n3$8ai$1@nnrp1.deja.com...
> 
> > <<Is goto statments particular slow?>>
> > No, the concern is not for efficiency at all!
> 
> You're the expert, of course, but I'm surprised by this answer. I thought
> that structured code in general allowed for easier determination of scope,
> making certain optimizations more likely to be applied.

It depends on the compiler.  In the old TeleSoft compiler, certain
optimizations were turned off for any scope containing a goto
statement.  This wasn't strictly necessary, but performing the
necessary analysis would have required substantial extra time
(development time, not necessarily compilation time), and it wasn't
considered worth the effort.

I suspect most compiler back-ends work on a lower level and are not as
easily intimidated by gotos.

As for stylistic concerns, IMHO gotos are very rarely appropriate.
The exceptions are: to simulate a structured construct missing from
the language (e.g., a multi-level break or exception handler in C, or
*possibly* a continue statement in Ada), or when a goto accurately
reflects the abstraction being modeled (e.g., in a finite state
machine).

-- 
Keith Thompson (The_Other_Keith) kst@cts.com  <http://www.ghoti.net/~kst>
San Diego Supercomputer Center           <*>  <http://www.sdsc.edu/~kst>
Welcome to the last year of the 20th century.