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! D I G I T A L ! Interoffice Memorandum
+---------------+
To: Users Date: 14-Jan-81
cc: Dept: LSG Soft. Eng.
Subj: COBOL-68 to COBOL-74 Conversion Utility
68274 is a conversion utility to aid in the conversion of legal version
12C COBOL-68 programs into legal version 12C 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 12C 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]