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+---------------+
! D I G I T A L !                       Interoffice Memorandum
+---------------+


To: Users                               Date: 14-Jan-81 
                                        From: David Nixon
cc:                                     Dept: LSG Soft. Eng.
                                        Ext.: 231-6378
                                        Loc.: MR1-2/E37

Subj: COBOL-68 to COBOL-74 Conversion Utility

68274 is a conversion utility to aid in the conversion of legal  version
12B  COBOL-68  programs into legal version 12B COBOL-74 programs.  There
is no guarantee that all programs can be converted without human help or
that  all  differences  will be found, though the utility will do a good
job on most programs.  What it will do is:  
1) It will try to convert a COBOL-68 program to a COBOL-74 one.
2) It will provide a listing flagging all things that either  could  not
be converted or may have been converted incorrectly.

The  utilty  is  a  variation  on  the  version  12B  COBOL-68  compiler
produced  by setting the feature test switch FT68274 to 1.  It will take
as input  a  COBOL  program  including  COPY  libraries  and  produce  a
converted source output (extension .CVT) and a listing (extension .LST).
It will NOT produce a binary file (extension .REL).  All COBOL  switches
will be valid but the only useful ones will be /S (card sequenced file),
/N (no errors on terminal).  The converted file will be the same  format
as  the  input  file  with as little change as possible so that a FILCOM
will show the differences.

68274 will work with all forms of source input.  Terminal input presents
no  problems  unless it contains line sequence numbers (such as produced
by SOS).  In this case every time a new line is created it  gets  for  a
line  number  1  greater  than  the previous line.  No effort is made to
check that this line number does not  already  exist,  therefore  it  is
recomended that all such files be resequenced before conversion.  If the
source is card image (/S) then each new line created will get  the  same
line number as the previous line and 68274 in the comment field (72-80).

1.0     How to build the converter.

Since the conversion utility is just another  version  of  COBOL-74  all
that  has  to be done to  build it  is to add FT68274==1 and ANS68==1  to
COBASM.MAC and set ANS74==0. Then rebuild the compiler in  the normal way
using COBOL.CTL (or the .CTM file on TOPS-10).  Then  put the .EXE  files
on SYS:.

2.0     Things that will be converted.

In general where a change is described as
"this will be made  into  a  comment  by  putting  an  asterisk  in  the
continuation column".
COBOL-68 to COBOL-74 Conversion Utility                           Page 2


It means that for the specified syntax only will this occur.   If  there
are  other words on the line either before or after the specified syntax
then the line will be broken into  two  or  more  parts  and  each  part
treated separately.

2.1     IDENTIFICATION DIVISION

DATE-COMPILED paragraph.
All comment lines after the  initial  line  will  have  a  asterisk  (*)
inserted  in  the  continuation  column  since COBOL-74 would delete the
lines otherwise.

REMARKS paragraph.
All lines, including the first one, will have a asterisk (*) inserted in
the continuation column since COBOL-74 would delete the lines otherwise.

2.2     ENVIRONMENT DIVISION

2.2.1   CONFIGURATION SECTION

No action required.

2.2.2   INPUT-OUTPUT SECTION

No action required.

2.2.3   FILE-CONTROL paragraph

FOR MULTIPLE REEL/UNIT
This will be  made  into  a  comment  by  putting  an  asterisk  in  the
continuation column.

RESERVE interger ALTERNATE AREAS
ALTERNATE will be deleted and interger will be incremented by 2.

RESERVE NO ALTERNATE AREAS
This will be changed to RESERVE 1 AREA.

FILE-LIMITS clause
This will be  made  into  a  comment  by  putting  an  asterisk  in  the
continuation column.

ACCESS MODE IS SEQUENTIAL 
This will be changed into ORGANIZATION IS SEQUENTIAL

ACCESS MODE IS RANDOM
This will be changed  to  ORGANIZATION  IS  RELATIVE;   ACCESS  MODE  IS
DYNAMIC

ACCESS MODE IS INDEXED
This will be changed to ORGANIZATION IS INDEXED;  ACCESS MODE IS DYNAMIC

PROCESSING MODE IS SEQUENTIAL
This will be changed to ACCESS MODE IS SEQUENTIAL
COBOL-68 to COBOL-74 Conversion Utility                           Page 3


ACTUAL KEY
This is changed to RELATIVE KEY.

SYMBOLIC/NOMINAL KEY clause
This will be  made  into  a  comment  by  putting  an  asterisk  in  the
continuation column.

2.2.4   I-O-CONTROL paragraph

No action required.

2.3     DATA DIVISION

2.3.1   FILE SECTION

LABEL RECORDS ARE record-name
This will be  made  into  a  comment  by  putting  an  asterisk  in  the
continuation  column.   It  will  also be flagged to warn the user of an
incompatible change.

2.3.2   DATA description entry

TALLY
TALLY is no longer generated automatically.  68274 does not know whether
TALLY will be required until it is too late so it always generates
01      TALLY PIC S9(5) COMP.

2.4     PROCEDURE DIVISION

EXAMINE
This  whole  statement  will  be  replaced  by  the  equivalent  INSPECT
statement.  Specifically the cases are:

     1.  EXAMINE identifier TALLYING ALL literal-1
         INSPECT identifier TALLYING TALLY FOR ALL literal-1

     2.  EXAMINE  identifier  TALLYING  ALL   literal-1   REPLACING   BY
         literal-2
         INSPECT identifier TALLYING TALLY FOR ALL  literal-1  REPLACING
         ALL literal-1 BY literal-2

     3.  EXAMINE identifier TALLYING LEADING literal-1
         INSPECT identifier TALLYING TALLY FOR LEADING literal-1

     4.  EXAMINE identifier  TALLYING  LEADING  literal-1  REPLACING  BY
         literal-2
         INSPECT  identifier  TALLYING  TALLY  FOR   LEADING   literal-1
         REPLACING LEADING literal-1 BY literal-2

     5.  EXAMINE identifier TALLYING UNTIL FIRST literal-1
         INSPECT identifier TALLYING TALLY FOR CHARACTERS BEFORE INITIAL
         literal-1
COBOL-68 to COBOL-74 Conversion Utility                           Page 4


     6.  EXAMINE identifier TALLYING UNTIL FIRST literal-1 REPLACING  BY
         literal-2
         INSPECT identifier TALLYING TALLY FOR CHARACTERS BEFORE INITIAL
         literal-1 REPLACING CHARACTERS BY literal-2

     7.  EXAMINE identifier REPLACING ALL literal-1 BY literal-2
         INSPECT identifier REPLACING ALL literal-1 BY literal-2

     8.  EXAMINE identifier REPLACING LEADING literal-1 BY literal-2
         INSPECT identifier REPLACING LEADING literal-1 BY literal-2

     9.  EXAMINE identifier REPLACING FIRST literal-1 BY literal-2
         INSPECT identifier REPLACING FIRST literal-1 BY literal-2

    10.  EXAMINE identifier REPLACING UNTIL FIRST literal-1 BY literal-2
         INSPECT identifier REPLACING  CHARACTERS  BY  literal-2  BEFORE
         INITIAL literal-1


GOBACK
This will be changed to EXIT PROGRAM

NOTE paragraph
This will be  made  into  a  comment  by  putting  an  asterisk  in  the
continuation column.

SEEK verb
This will be  made  into  a  comment  by  putting  an  asterisk  in  the
continuation  column.   It  will  also be flagged to warn the user of an
incompatible change.

USE LABEL PROCEDURE
This will be  made  into  a  comment  by  putting  an  asterisk  in  the
continuation  column.   It  will  also be flagged to warn the user of an
incompatible change.

WRITE record-name.
If the file is ASCII and  the  WRITE  would  have  defaulted  to  BEFORE
ADVANCING in COBOL-68 then the clause is changed to explicitly be:
WRITE record-name BEFORE ADVANCING 1 LINE
since the default in COBOL-74 is AFTER 1 LINE.

3.0     Things that will be flagged.

The flagging messages are of two kinds:
1)Those the program would get if compiled with COBOL-74
2)Messages warning of impossible or possibly incorrect conversions
In addition  all  COBOL-68  fatal  and  warning  messages  (with  a  few
exceptions)  will  be  output incase the program is not a legal COBOL-68
one.

3.1     IDENTIFICATION DIVISION

Nothing is flagged.
COBOL-68 to COBOL-74 Conversion Utility                           Page 5


3.2     ENVIRONMENT DIVISION

3.2.1   CONFIGURATION SECTION

SWITCH (n)
Switches are defined differently in COBOL-74, therefore all  definitions
of SWITCH will be flagged.

3.2.2   INPUT-OUTPUT SECTION

Nothing is flagged.

3.2.3   FILE-CONTROL paragraph

ACCESS MODE IS RANDOM
This will be changed to ORGANIZATION IS RELATIVE
and then flagged warning user that
ACCESS MODE IS DYNAMIC has been assumed.

ACCESS MODE IS INDEXED
This will be changed to ORGANIZATION IS INDEXED
and then flagged warning user that
ACCESS MODE IS DYNAMIC has been assumed.

3.2.4   I-O-CONTROL paragraph

Nothing is flagged.

3.3     DATA DIVISION

3.3.1   FILE SECTION

LABEL RECORDS ARE record-name
This will be flagged as no longer legal in COBOL-74.

3.3.2   DATA description entry

BLANK WHEN ZERO
BLANK WHEN ZERO and asterisk (*) as zero suppression symbol in a PICTURE
clause may not appear in the same entry.

CURRENCY SIGN
The characters "L", "/", and "=" may not be specified  in  the  CURRENCY
SIGN clause.

TODAY
TODAY is no longer  generated  automatically.   In  COBOL-68  it  has  a
definition of:
01      TODAY PIC X(12).
where the contents of TODAY is yymmddhhmmss
where   yy = year
        mm = month
        dd = day
        hh = hour
        mm = minute
COBOL-68 to COBOL-74 Conversion Utility                           Page 6


        ss = second
It would be possible to construct TODAY in COBOL-74 as:
01      TODAY.
        02 68274-TODAY-DATE PIC X(6).
        02 68274-TODAY-TIME PIC x(6).
and in the PROCEDURE DIVISION before every reference of TODAY do:
ACCEPT 68274-TODAY-DATE FROM DATE.
ACCEPT 68274-TODAY-TIME FROM TIME.
However this is probably not what the user want so all  we  will  do  is
flag  all  references to TODAY and warn the user to do the conversion by
hand.

VALUE clause in PICTURE
In COBOL-74 VALUE is initialized independent of  JUSTIFIED  clause.   If
this is different from COBOL-68 the JUSTIFIED clause will be flagged.

3.4     PROCEDURE DIVISION

IF abreviated combined relation condition.
If NOT is immediately followed by  a  relational  operator  it  will  be
flagged as possibly having a different meaning in COBOL-74.

IF comparison of non-numeric operands
If one operand is numeric it is treated as though it were  moved  to  an
alphanumeric item of the same size and the contents of this alphanumeric
item compared to the non-numeric operand.

MOVE LOW-VALUE TO some-kind-of-key
If some-kind-of-key is an ACTUAL KEY (for a RANDOM file) or  a  SYMBOLIC
KEY or RECORD KEY (for an ISAM file), and a MOVE of LOW-VALUE is done to
it or to a data-item subordinate to it, then what is  probably  required
is a READ NEXT or a START with approximate key.  Since we do not do flow
analysis it is impossible to do the conversion correctly so the  utility
will  flag  all such references to LOW-VALUES.  Note it will not be able
to detect the case of MOVE LOW-VALUES TO data-item,  MOVE  data-item  TO
some-kind-of-key.

STRING/UNSTRING DELIMITED BY ALL literal/data-name DELIMITER IN item-1
If there are consecutive occurences of delimiter and  item-1  is  bigger
than  delimiter,  then  COBOL-74  will  contain  only  one  occurence of
delimiter,  whereas  COBOL-68  will  contain  the  actual  text  of  the
delimiter.

3.5     RESERVED WORDS

There are several valid COBOL-68 user-names that are reserved  words  in
COBOL-74.  These words will be flagged but not changed.

These words are:

    ALSO                  END-OF-PAGE           REFERENCES
    BOTTOM                EOP                   REMOVAL
    CHARACTER             EXCEPTION             RMS
    CODE-SET              INSPECT               SEPARATE
    COLLATING             LINAGE                SORT-MERGE
COBOL-68 to COBOL-74 Conversion Utility                           Page 7


    DAY                   LINAGE-COUNTER        STANDARD-1
    DEBUGGING             NATIVE                START
    DUPLICATES            ORGANIZATION          TOP
    DYNAMIC               PRINTING              TRAILING
    EBCDIC                PROCEDURES

4.0 COPY LIBRARY code.

Text copied from a copy library with a COPY  verb  presrents  a  special
problem.   Clearly  the  text  should  be  converted  and/or checked for
problems.  Checking presents no special problem since the  library  text
will  be expanded as usual in the listing file and all errors will point
to the correct place.  However the source does present a  problem.   The
solution chosen while perhaps not the best is at least simple.  The COPY
verb up to the following period will be made into a comment.   The  body
of  the  copied  text  will  then  appear  in  the converted (.CVT) file
surrounded by comment lines.  The effect will be:
*   COPY FOO OF "BAR   .LIB".
***** Start of copy library text *****
    TEXT COPIED FROM FOO
***** end of copy library text *****

The effect of this is that the .CVT file can be compiled "as is" so  the
converted  copy  library  text  can  be removed and replace the existing
contents of the library.  However there  is  a  problem  with  SOS  line
numbers.   If the source has line numbers then the copied code must also
have line numbers or else it cannot be edited.  If the copy library text
has  line  numbers  they  will be replaced by new line numbers generated
from the last source line number seen, adding 1 for each new  line.   If
the  copy  library  text  does  not  have line numbers then they will be
supplied using the above algorithm.


[End of 68274]