Re(2): My take on GOTO

["Mike Naughton" <mnaughton@xxxxxxxxxxxx>]

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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