#1197 DISPLAY strange behavior.

[Eugenio Di Lorenzo]

The following program exhibits strange behavior.
The fourth DISPLAYstatement, in which I commented out the two "END-DISPLAY" clause (which are not required by GnuCOBOL syntax), behaves strangely.
The program doesn't execute the "NOT ON EXCEPTION" statement but terminates without reporting errors.
The NOT ON EXCEPTION clause should still terminate what is included in the previous ON EXCEPTION clause.
I believe this can be classified as a BUG.

        >>SOURCE FREE
IDENTIFICATION   DIVISION.
PROGRAM-ID.      TESTDISPLAY01.

PROCEDURE DIVISION.
DISPLAY ' INIT' AT 0101 BACKGROUND-COLOR 2 FOREGROUND-COLOR 1 WITH ERASE EOS

display '01 ... 1234567890'  AT 0302 BACKGROUND-COLOR 6 FOREGROUND-COLOR 1  
    on exception      display 'EXCEPTION 1'        AT 0502 end-display
    not on exception  display 'NOT ON EXCEPTION 1' AT 0702 end-display
end-display

display ' POST DISPLAY 1 ' AT 0902 BACKGROUND-COLOR 7 FOREGROUND-COLOR 1 
accept omitted AT 1001

*> ***************************************************************************
*> FOLLOWING DISPLAY HAS STRANGE BEHAVIOR. "not on exception" is NOT EXECUTED. 
*> BUT PROGRAM ENDS HERE !!!  NORMAL END WITHOUT ERRORS !!! 
*> ***************************************************************************
display '02 ... 1234567890'  AT 1202 BACKGROUND-COLOR 6 FOREGROUND-COLOR 1  
    on exception      display 'EXCEPTION 2'        AT 1402 *> end-display   
    not on exception  display 'NOT ON EXCEPTION 2' AT 1602 *> end-display
end-display
*> end-display  *> With these two END-DISPLAY it works correctly
*> end-display

display ' POST DISPLAY 2 ' AT 1802 BACKGROUND-COLOR 7 FOREGROUND-COLOR 1 *> NOT EXECUTED 
accept omitted AT 2001 *> NOT EXCEUTED

goback.

[Chuck Haatvedt]

I don't think that this is a bug, note that the "not on exception is not part of the following statement. This is an end of scope scenario. Find the end of scope on each of the statements in your program. This is a good example of coding a "." at the end of each independent code statement would have resolved the issue.

display '02 ... 1234567890'  AT 1202 BACKGROUND-COLOR 6 FOREGROUND-COLOR 1

it is part of this statement

display 'EXCEPTION 2'        AT 1402

For example.... Note that I added a period (hard end of scope) at the end of what appears to each independent statement.

        >>SOURCE FREE
IDENTIFICATION   DIVISION.
PROGRAM-ID.      TESTDISPLAY01.

PROCEDURE DIVISION.
DISPLAY ' INIT' AT 0101 BACKGROUND-COLOR 2 FOREGROUND-COLOR 1 WITH ERASE EOS.

display '01 ... 1234567890'  AT 0302 BACKGROUND-COLOR 6 FOREGROUND-COLOR 1  
    on exception      display 'EXCEPTION 1'        AT 0502 end-display
    not on exception  display 'NOT ON EXCEPTION 1' AT 0702 end-display
end-display.

display ' POST DISPLAY 1 ' AT 0902 BACKGROUND-COLOR 7 FOREGROUND-COLOR 1.
accept omitted AT 1001.

*> ***************************************************************************
*> FOLLOWING DISPLAY HAS STRANGE BEHAVIOR. "not on exception" is NOT EXECUTED. 
*> BUT PROGRAM ENDS HERE !!!  NORMAL END WITHOUT ERRORS !!! 
*> ***************************************************************************
display '02 ... 1234567890'  AT 1202 BACKGROUND-COLOR 6 FOREGROUND-COLOR 1  
    on exception      display 'EXCEPTION 2'        AT 1402 *> end-display   
    not on exception  display 'NOT ON EXCEPTION 2' AT 1602 *> end-display
end-display.
*> end-display  *> With these two END-DISPLAY it works correctly
*> end-display

display ' POST DISPLAY 2 ' AT 1802 BACKGROUND-COLOR 7 FOREGROUND-COLOR 1. *> NOT EXECUTED 
accept omitted AT 2001. *> NOT EXCEUTED

goback.

[Simon Sobisch]

Note that MF does not support the exception part together with AT at all; if you remove all of those then it still doesn't compile...
Nor does ACUCOBOL - but if you rewrite that to use CALL then we can compare the results with the DISPLAY and also to the CALL scoping of MF and ACU.