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Date:	Sun, 1 Nov 1998 12:21:22 PDT
From:	"Gregory W. Smith" <gsmith@well.com >
Reply-To:	scoug-programming@scoug.com
To:	< "scoug-programming@scoug.com" > scoug-programming@scoug.com >
Subject:	SCOUG-Programming: Pipes and REXX

Content Type: text/plain

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On Sun, 1 Nov 1998 11:20:38 PDT, Steven Levine wrote:

>In <199811011535.HAA07465@smtp.well.com>, on 11/01/98
> at 07:35 AM, "Gregory W. Smith" said:
>
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>
>>On Sat, 31 Oct 1998 18:23:46 PDT, Steven Levine wrote:
>>>In <199811010025.QAA19174@smtp.well.com>, on 10/31/98
>>> at 04:25 PM, "Gregory W. Smith" said:
>>>
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>>>
>>>>Is there an elegant way to invoke a command from within REXX and have it
>>>>redirect the output to the standard input? Right now I am using pipes as
>>>>in the example:
>>>
>>>I suspect you want to invoke bar and pipe it's output to RXQUEUE:
>>>
>>> 'bar | rxqueue'
>>>
>>>Then use
>>>
>>> parse pull
>
>>So I have to replace all of my calls to IO functions such as linein() and
>>charin() with a 'parse pull somevariable' instruction? Then use
>>'somevariable' in the expression in place of linein().
>
>Yes, your logic will look something like:
>
> do while queued() \= 0
> parse pull line
> /* Process line */
> end
>
>The logic is the same. queued() replaces lines() and pull replaces linein.
>
>> It seems a lot easier to just replace the calls to linein() with calls
>>to linein('\temp\tempjunk') and just use tempoarary files. Besides, I
>
>It's your call. RXQUEUE will be faster because there will be no file I/O.
>Makes a difference if you are filtering a lot of data.
>
>>would have to re-do the logic of my program since I was already using a
>>stack. I would have to check after each 'parse pull' to see if I had the
>>re-directed STDIN or if I had stack data.
>
>I'm missing something here. Doesn't queued() do the test you need or are
>use already using the RXQUEUE?

I was already using the push and queue for other reasons in my program.
My program structure is something like this:

/* Main processing loop */

do while lines() > 0
linetoprocess = linein()
.....
if ....... then /* Save something for final output */
do
....
push 'Some temporary results ' || moreprocessing(linetoprocess)
end
....
end /* main processing loop */

/* final cleanup */

do while queued() > 0
parse pull savedresults
say savedresults
end /* final cleanup loop */
exit
===============================================================
Gregory W. Smith (WD9GAY) gsmith@well.com
finger gsmith@well.com for PGP public key
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