Is this a BUG ?? - Substitute command.

[David Wall]

I have a string field XXX with the following data.: ++ are blanks. Difficult to represent here.
++++++++GO+NXT+NXT+NXT+DEPENDING+ON+NXTNUM.
I want to change the NXT fields for ABC such that the line now says:
++++++++GO+ABC+ABC+ABC+DEPENDING+ON+NXTNUM.

Now - noting that I don't want to change NXTNUM to become ABCNUM I did the following.
Inspect XXX replacing all "+" by "@". ie: change all spaces to @ signs.
now I did a: MOVE Substitute (XXX "@NXT@" "@ABC@") to YYY.
followed by a reverse: Inspect YYY replacing all "@" by "+". ie: change all the @ signs back to spaces.
and got the following result:
++++++++GO+ABC+NXT+ABC+DEPENDING+ON+NXTNUM.

The question is - should the substitute NOT HAVE ALSO changed the middle NXT to ABC ??.

The manual says the following:

This function parses string, replacing all occurrences of from-n strings with the corresponding
to-n strings. My Highlighting.

Sample program duplicating the above with comments attached.

[Emmad]

It looks like you are correct. Maybe after the first replace, the pointer that records current position in the from-string gets incremented by 1 and does not recognize @NXT@ as it is but recognize it as NXT@ only, accordingly it does not replace it.
I tried to convert what you said into a small test program. The last case shows a simpler version of the problem:

IDENTIFICATION DIVISION.
PROGRAM-ID. test.
DATA DIVISION.
WORKING-STORAGE SECTION.
01 xxx           pic x(40).
01 YYY           pic x(40).
01 ORIGINAL-XXX  PIC X(40).
PROCEDURE DIVISION.

MOVE "    GO NXT NXT NXT DEPENDING ON NXTCNT. " TO ORIGINAL-XXX
MOVE ORIGINAL-XXX TO XXX

MOVE FUNCTION SUBSTITUTE (XXX "NXT" "ABC") TO YYY.

DISPLAY "1: " YYY
 *> YYY = GO ABC ABC ABC DEPENDING ON ABCCNT. "

 INSPECT XXX REPLACING ALL " " BY "@".
 DISPLAY "2: " XXX
 *> @@@@GO@NXT@NXT@NXT@DEPENDING@ON@NXTCNT.@
 MOVE FUNCTION SUBSTITUTE (XXX "@NXT@" "@ABC@") TO YYY.
 DISPLAY "3: " YYY 
 *>  @@@@GO@ABC@NXT@ABC@DEPENDING@ON@NXTCNT.@
 *> EXPECTED
 *>  @@@@GO@ABC@ABC@ABC@DEPENDING@ON@NXTCNT.@
 *>            ---------              
 INSPECT YYY REPLACING ALL "@" BY " ".
DISPLAY "4: " YYY
*>      GO ABC NXT ABC DEPENDING ON NXTCNT. 

*> My Guess:
*> IF AN EXTRA @ IS USED FOLLOWING NXT, IT WORKS
MOVE "@@@NXT@@NXT@" TO XXX
MOVE FUNCTION SUBSTITUTE (XXX "@NXT@" "@ABC@") TO YYY.
DISPLAY YYY
*> @@@ABC@@ABC@
STOP RUN.

[Simon Sobisch]

Works "as designed", which is like Emmad guessed a "pointer wise" change; text that already got replaced - in your case the trailing @ of @NXT@ - should not be re-inspected.

Note: In this special case (length are identical) I'd suggest to use INSPECT instead of FUNCTION SUBSTITUTE, but if you need to inspect the full context left/right you may want to loop over the text.

[David Wall]

Inspect replacing fails the same way. I end up with ABC NXT ABC.
Perhaps the 'as designed' needs a repair.
as the manual says replace all occurrences - it's an occurrence - it just falls as part of an existing occurrence.

OK - hows about I pose this question.

A field contains the following - where a + is actually a space.
How do I replace ALL occurrences of NXT (ONLY) with ABC.

++++++GO+NXT+NXT+NXT+DEPENDING+ON+NXTCNT that gives me
++++++GO+ABC+ABC+ABC+DEPENDING +ON+NXTCNT.

[Simon Sobisch]

I assume you don't meant the manual but the Programmer's Guide. In this case please create a bug report for Vince to adjust it, ideally with a suggestion how it should be changed.

[David Wall]

YES as you say - looping over does the trick - eventually.

[Simon Sobisch]

Either looping or applying SUBSTITUTE more than once (three times should work for everything).

[David Wall]

At least 1 thing I've learned from this - you can Move substitute (AAA BBB CCC) to AAA.
Source & Destination can be the same.
I've always done the move from AAA to XXX & then moved back again.