Re: My take on GOTO

[Jim Langston <jimlangston@xxxxxxxxxxxxxxxx>]

If (A<12)
  <do stuff>
Else
  If(B=7)
    <do other stuff>
  Else
    If(A>4)
      <do something completely different>
    End
  End
End

Isn't it more obvious now?

Taking it farther...

If (A<12)
  <do stuff>
ElseIf(B=7)
  <do other stuff>
ElseIf (A>4)
  <do something completely different>
EndIf

Now it's even more obvious.  And lastly...

Select
Case (A<12)
  <do stuff>
Case (B=7)
  <do other stuff>
Case (A>4)
  <do something completely different>
EndSl

Now it is really obvious.

All 4 sections of code do the exact same thing.  One using goto,
one using if/else/endif one using if/elseif/endif and one using
Select.  The farther away from GOTO we get the more obvious flaws
become.

Regards,

Jim Langston

Mike Naughton wrote:
> 
> RPG400-L@midrange.com writes:
> >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)
> >   .
> >
> <!snip!>
> >
> >Is it obvious that (Some Stuff 2) will never get executed?
> 
> Jim,
> In fairness, the useless code is not caused by the GOTOs. Consider this:
> 
> If (A<12)
> <do stuff>
> Else
> If(B=7)
> <do other stuff>
> Else
> If(A>4)
> <do something completely different>
> End
> End
> End
> 
> Note that "something completely different" will never be executed for
> 4<A<12, but you'd never know it just from looking at that section of code.
> Put the nested test in a subroutine, and it gets even harder to track down
> -- and I haven't used a single GOTO! And this is just a simple example --
> I hope it's obvious that it wouldn't be hard to come up with much more
> complicated ones.
> 
> I don't see how we get around the fact that for any reasonably complex
> program (the kind we're paid to write ;-)), it's usually necessary to
> spend time tracing just what-the-heck the program does (and doesn't do).
> The only exception is when it has been written in a style (and using
> standards) that you are thoroughly familiar with (and, IMHO, whether those
> standards allow the use of GOTO is entirely irrelevant to the question of
> how readable the code is).
> 
> Mike Naughton
> Senior Programmer/Analyst
> Judd Wire, Inc.
> 124 Turnpike Road
> Turners Falls, MA  01376
> 413-863-4357 x444
> mnaughton@juddwire.com
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