Re: DOW vs DOU

[Francis Lapeyre <flapeyre@xxxxxxxxxxxxxx>]

Susan Durrie wrote:
> 
> On May 26, 1997, David Kahn replied as follows:
> 
> >On May 25 1997 John P. Carr wrote:
> 
> >Ok David; (Mr Phelps)
> >
> >Here's your assignment if you chose to accept it, Convert the following
> >code of that infamous DOU connoisseur guy  John Carr to a DOW.
> 
> >Like this, you mean?
> 
>   KEY       CHAINFILEXXX              90
> 
>   *IN90     DOWEQ*OFF
>   XXCODE    ANDNE'B'
> 
>   XXCODE    IFEQ 'A'
>             ITER
>             ENDIF
> 
>  <.... whatever process ....>
> 
>   KEY       READEFILEXXX                  90
>             ENDDO
> 
> Correct me if I'm wrong, but if XXCODE='A', aren't you in an
> infinite loop?
> 
> And just to stir up trouble, I'll throw in the following that I
> use in certain circumstances:
> 
>    KEY       CHAINFILEXXX              90
> 
>   *IN90     DOWEQ*OFF
>   XXCODE    ANDNE'B'
> 
>   XXCODE    CABEQ'A'     NXTRCD
> 
>  <.... whatever process ....>
> 
>   NXTRCD    TAG
>   KEY       READEFILEXXX                  90
>             ENDDO
> 
> Just could not resist throwing my two cents worth in on this one.  I'm
> new to the mailing list; subscribed on the advice of Charlie Massoglia
> after attending one of his excellent seminars.  The rewards have been
> well worth the time expended.
> 
> Susan Durrie

If XXCODE=A, you won't be in an infinite loop. Unlss, of couse, XXCODE
is never modified in the body of the loop. Eventually, the file will
end, *IN90=*ON, and you're out of the loop.

I try to avoid the use of TAGs, also, I'd condition the loop on the EOF
indicator alone. Any other conditions should be inside the loop proper,
with ITER or LEAVE, as appropriate, for a "no-hit". I don't like the use
of two READ statements in a loop; with some sloppy coding I've seen, you
have to stop and think.. "Is this ANOTHER loop, or the same one?" I hate
having to compile the thing just o get a listing so I can see how it's
structured.

Too many GOTO's lead to "spaghetti" code, a tangled mess for the next
poor fellow who has to work on it. Pass the Parmesan.

-- 
Francis Lapeyre                    flapeyre@communique.net
----------------------------------------------------------
"The probability of life originating from accident is 
comparable to the probability of the Unabridged Dictionary
resulting from an explosion in a printing factory." 

Prof. Edwin Conklin

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Opinions are my own. Otherwise, they are someone else's.
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