Re: My take on GOTO -- RPG400-L

I have had to maintain other people's code where they used the GOTO statement.

There would be things like...


:Tag1
   (Some Stuff 1)
   .
   .
   .
  If (B = 7) Goto Tag3
  If (A > 12) Goto Tag1
  If (A < 13) Goto Tag2
   (Some Stuff 2)
   .
   .
   .
:Tag2
   (Some Stuff 3)
   .
   .
   .
   Goto Tag1
   (Some Stuff 4)
   .
   .
   .
:Tag3
   (Some Stuff 5)
   .
   .
   .
End Of Program

and I have to maintain this stuff.  This is light compared to what I've seen.
Is it obvious that (Some Stuff 2) will never get executed?  And don't think 
that's
the exception, in almost every one of these programs I was maintaining I would
find whole blocks of code that could never get executed, and you wouldn't 
realize
it until you traced through this spagetti to find out how it actually flows.

When is the program over?  Well, whenever it hits the End Of Program.  So you 
have
to go back and see that it flows from Tag 3, or did it drop through from (Some 
Stuff 4) ?
So you start to trace (Some Stuff 4) and realize it can never be executed 
either!  
Then you see it goes to Tag3 when B = 7.  Where is B set?  Oh, shoot, it's set 
everywhere.
Which part of the code sets it just before the comparison?  Was it from (Some 
Stuff 1),
or some other block of code before it jumped to 1?

Do not think this is in any way an exaggeration, this is tame compared to the 
spagetti
I had to wade thought to make a simple program modification.  Something that 
would take me
maybe 2 minutes in a structred program now takes me 2 to 3 hours.

After I figured out what the program was supposed to do I would rearrange it 
for top
down logic.  By the time I was gone 2/3 of the program would be gone!  Never 
executed code,
redundant code, endless loops.  Now, someone has to come in and make a change, 
it's a 2
minute job, not an all day affair.

THAT is what is so bad about GOTO.

When computers had 48k of memory total to run a program in and a 520k floppy to 
store data
on, goto had it's place.  Do as much as you can in as little as you can, 
otherwise, you just
can't do it.  But now, with our available DASD and memory, there is no need.

Regards,

Jim Langston

Ken.Slaugh@cm-inc.com wrote:
> 
> Go Brad,
> 
>      I've always wondered why the GOTO statement was so bad. Nobody has
> ever proven it's problems, if there actually is any. It just always seems
> to be just an opinion.
> 
> Opinions are like A-Holes, everyone has one.
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