RE: %EOF - more on GOTO

["Ken & Gloria Cox" <kgc@xxxxxxxxxx>]

Lets remove the jump instruction out of machine language and do away with
computers completely.
It's there, and it's certainly easier to read then some of endif
manipulation I have seen
to get back to a certain point. The two points I try to make, Does the
program work,
and how easy is it for another programmer to read the code.  Now indicators
are a completely
different story and IBM forces us in some cases to use them.

-----Original Message-----
From: owner-rpg400-l@midrange.com [mailto:owner-rpg400-l@midrange.com]On
Behalf Of Joel Fritz
Sent: Friday, June 18, 1999 6:42 PM
To: 'RPG400-L@midrange.com'
Subject: RE: %EOF - more on GOTO


It may be a matter of taste, but I think this is a situation that SELECT
would handle simply and elegantly.


-----Original Message-----
From: John Taylor [mailto:john.taylor@telusplanet.net]
Sent: Friday, June 18, 1999 3:39 PM
To: RPG400-L@midrange.com
Subject: RE: %EOF - more on GOTO




> -----Original Message-----
> From: owner-rpg400-l@midrange.com [mailto:owner-rpg400-l@midrange.com]On
> Behalf Of bellis@ORIENTAL.COM
> Sent: Friday, June 18, 1999 3:01 PM
> To: RPG400-L@midrange.com
> Subject: RE: %EOF
>


<snipped>

> By the way, you should never have to use a GOTO in an RPG program !!!

No, you never really HAVE to. However, when used responsibly, a GOTO can be
quite usefull. Take for example a standard error checking subroutine such as
the following:

SR      ChkForErr       BegSR

  * Initialize routine
C                       Eval    ErrorID = *Blanks

  * Do some testing & branch to error section when required
C                       If      ( SomeCondition <> Valid )
C                       Eval    ErrorID = "SomeErrorID"
C                       Goto    ErrSection
C                       Endif

C                       If      ( SomeOtherCondition <> Valid )
C                       Eval    ErrorID = "SomeOtherErrorID"
C                       Goto    ErrSection
C                       Endif

  * Add a whole bunch of other tests here


  * Error Section
C       ErrSection      Tag
C                       If      ( ErrorID <> *Blanks )
C                       Eval    DspErrInd = *On
  *    <add additional common error handling code here)
C                       Endif

SR                      EndSR


Sure, you could code this without using a GOTO, but it would mean adding
more code that is just not necessary. The routine only exits at one point,
and the logic does not jump around from place to place.

The bottom line, for me, is that the GOTO is not evil. The programmer who
uses it irresponsibly is. And a programmer who abuses the GOTO statement is
also likely to abuse any other op-code that he's learned. How many times
have you seen code that moves *BLANKS into a decimal field?


John Taylor

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