COBOL UNSTRING negative numeric string

[meyer_d]

I'm using the VAX COBOL compiler.

The UNSTRING statement can parse a string of numeric characters into a display numeric item (PIC 9(n)), but terminates with the error '%COB-F-INVDECDIG, invalid decimal digit: "-"' if the numeric string has a leading or trailing negative sign, even if the receiving item is declared PIC S9(n). Is there any way to get UNSTRING (or another statement) to parse an input negative number?

[hein]

VAX ? Really? Compiler/rtl/vms version?

Did the behavior change or is this a first try?

Can you perhaps post a small working (well, failing) example to make it easier for us to try on Alpha or Itanium... or X86?
If this is a bug it may well have been fixed.

Hein.

[arne_v]

I don't do COBOL and this is on VMS x86-64 not VAX, but:

Code: Select all

$ type usdemo.cob
identification division.
program-id.usdemo.
*
data division.
working-storage section.
01 ui pic 9(8) display.
01 si pic s9(8) display.
01 t  pic x(10).
*
procedure division.
main-paragraph.
    move 10 to ui
    display "unsigned 10 = " ui
    move 10 to si
    display "signed 10   = " si
    move -10 to si
    display "signed -10  = " si
    move "10" to t
    unstring t into ui
    display t " -> " ui
    move "10" to t
    unstring t into si
    display t " -> " si
    move "-10" to t
    unstring t into si
    display t " -> " si " (WRONG)"
    move "1}" to t
    unstring t into si
    display t " -> " si " (WRONG)"
    move "-10" to t
    compute si = function numval(t)
    display "numval(" t ") = " si
    stop run.
$ cob usdemo
$ lin usdemo
$ run usdemo
unsigned 10 = 00000010
signed 10   = 0000001{
signed -10  = 0000001}
10         -> 00000010
10         -> 0000001{
-10        -> 0000001{ (WRONG)
1}         -> 0000000A (WRONG)
numval(-10       ) = 0000001}

You could try if the NUMVAL function works on VAX.

[meyer_d]

VAX ? Really? Compiler/rtl/vms version?

Yes, really. I'm using a VAX 7000/640 (Living Computer's ROSENCRANTZ host; I think it's running on real hardware) running OpenVMS V7.3. The compiler is Digital VAX COBOL V5.5-56. I don't know where to look-up the RTL version.

Did the behavior change or is this a first try?

First try. I'm re-learning COBOL by working through programming problems on CodeAbbey.com, many of which assume that you can feed numeric test data to the program from the user's terminal. I realize that this kind of interaction is not really COBOL's design target, and that it would not be to hard to write my own string-to-numeric parser, but I'd like to see how much I can accomplish with facilities that are build-in to COBOL-85.

Can you perhaps post a small working (well, failing) example to make it easier for us to try on Alpha or Itanium... or X86?

Code: Select all

       IDENTIFICATION DIVISION.
       PROGRAM-ID. TUNST.
      * TUNST - TEST UNSTRING COMMAND

       DATA DIVISION.
       WORKING-STORAGE SECTION.

       01  SOURCE-STR  PIC X(80)  VALUE '-8'.
       01  N  PIC S9(6).

       PROCEDURE DIVISION.

       MAIN.
           DISPLAY 'PROGRAM TUNST'.
           UNSTRING SOURCE-STR DELIMITED BY SPACE INTO N.
           DISPLAY 'N: /', N, '/'.
           STOP RUN.

Here's how it fails:

Code: Select all

 $ run tunst
PROGRAM TUNST
%COB-F-INVDECDIG, invalid decimal digit: "-"
%TRACE-F-TRACEBACK, symbolic stack dump follows
module name     routine name                     line       rel PC    abs PC

                                                           00079145  00079145

Added in 12 minutes 20 seconds:

You could try if the NUMVAL function works on VAX.

It looks like VAX COBOL has NUMVAL, and it might do the trick for me.

Code: Select all

       IDENTIFICATION DIVISION.
       PROGRAM-ID. TNUMVAL.

       DATA DIVISION.
       WORKING-STORAGE SECTION.

       01  SOURCE-STR  PIC X(80)  VALUE '-8'.
       01  N  PIC S9(6).

       PROCEDURE DIVISION.

       MAIN.
           DISPLAY 'PROGRAM TNUMVAL'.
           COMPUTE N = FUNCTION NUMVAL(SOURCE-STR).
           DISPLAY 'N: /', N, '/'.
           STOP RUN.

Code: Select all

 $ RUN TNUMVAL
PROGRAM TNUMVAL
N: /00000Q/

Which is how you say '-8' in COBOL.

... Though it would still be neater if there were a way to get UNSTRING to parse negative numbers since it can do the trick for positives.

[hein]

I tried a few things, but no joy with UNSTRING. It does not interpret the data. Per doc:
"dest-string - is the identifier of an alphanumeric, alphabetic, or numeric DISPLAY data item. It is the receiving field for the data from src-string"

The backend move from the unstringed element into the dest-string, seems check better on the VAX, but neither 'properly' interpret the string. In Integrity you for example can get: N: /0000-8/ - no error, but no good either. It's better to have the error.

To use UNSTRING for free format number parsing you'd have to do something like UNSTRING ...
DELIMITED BY "-" OR ALL " " DELIMITER IN delim-dest. Yuck.


>>> N: /00000Q/ .... Which is how you say '-8' in COBOL.

YES , for straight S9(x) becoming a trailing overpunch.

To 'see' the sign you would need 01 N PIC S9(6) SIGN LEADING|TRAIING SEPARATE.

So indeed best go NUMVAL COBOL intrinsic, or one of the LIB$ VMS routines.
Hein.

Code: Select all

Table 5–11 Positive and Negative Signs for All Numeric Digits
Digit Values Positive Sign Negative Sign
0 {, [, ?, or 0 }, ], :, or !
1 A or 1 J
2 B or 2 K
3 C or 3 L
4 D or 4 M
5 E or 5 N
6 F or 6 O
7 G or 7 P
8 H or 8 Q
9 I or 9 R

[arne_v]

I still think it is something that should be fixed.

It does work in GNUCobol:

Code: Select all

C:\Work\Cobol>type usdemo.cob
identification division.
program-id.usdemo.

data division.
working-storage section.
01 ui pic 9(8) display.
01 si pic s9(8) display.
01 t  pic x(10).

procedure division.
main-paragraph.
    move 10 to ui
    display "unsigned 10 = " ui
    move 10 to si
    display "signed 10   = " si
    move -10 to si
    display "signed -10  = " si
    move "10" to t
    unstring t into ui
    display t " -> " ui
    move "10" to t
    unstring t into si
    display t " -> " si
    move "-10" to t
    unstring t into si
    display t " -> " si " (CORRECT)"
    move "1}" to t
    unstring t into si
    display t " -> " si " (WRONG)"
    move "-10" to t
    compute si = function numval(t)
    display "numval(" t ") = " si
    stop run.

C:\Work\Cobol>runcob usdemo

C:\Work\Cobol>call "C:\Native\32bit\GC32-BDB\set_env.cmd"

Information: batch was called alread from "C:\Native\32bit\GC32-BDB\"
             skipping environment setting...

cobc (GnuCOBOL) 3.2.0
Copyright (C) 2023 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <https://gnu.org/licenses/gpl.html>
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
Written by Keisuke Nishida, Roger While, Ron Norman, Simon Sobisch, Edward Hart
Built     Jul 28 2023 19:10:09
Packaged  Jul 28 2023 17:02:56 UTC
C version (MinGW) "9.2.0"

GnuCOBOL 3.2.0 (Jul 28 2023 19:08:58), (MinGW) "9.2.0"
GMP 6.2.1, cJSON 1.7.14, PDCursesMod 4.3.7, BDB 18.1.40

C:\Work\Cobol>cobc -Wall -O3 -free -x usdemo.cob

C:\Work\Cobol>usdemo
unsigned 10 = 00000010
signed 10   = +00000010
signed -10  = -00000010
10         -> 00000010
10         -> +00000010
-10        -> -00000010 (CORRECT)
1}         -> +00000001 (WRONG)
numval(-10       ) = -00000010

Added in 14 minutes 37 seconds:
To be more specific:
- the VAX behavior of giving an error is OK (but does not matter much as there will be no fixes for VAX anyway)
- the newer behavior of giving wrong result is not OK and should be fixed