FROM: FRED SMITH

SUBJECT: COBOL FILTER PROGRAM

DATE: JULY 13, 1973


THE COBOL FILTER PROGRAM CONSISTS OF A MAIN COBOL PROGRAM WITH
2 SUBROUTINES - 1 WRITTEN IN COBOL AND 1 WRITTEN IN MACRO-10.
ALL 3 PROGRAMS MUST BE COMPILED TO PRODUCE .REL FILES AND THEN
LOADED TOGETHER AND SAVED. THE COMMANDS FOR THIS ARE:

.COMPILE FILTER
.COMPILE SCANIT
.COMPILE PUTREC
.LOAD FILTER,SCANIT,PUTREC
.SAVE FILTER

THE .SAV VERSION IS NOW READY TO RUN.
IT IS EXECUTED BY THE COMMAND:

.RUN FILTER

>ENTER COMMAND STRING AS: FN.EXT[PPN]/SWITCH_FN.EXT[PPN]/SWITCH


1. THE BASIS OF THE PROGRAM WAS THE EXISTING IBM FILTER PROGRAM
   CALLED IBMCOB.CBL WHICH WAS WRITTEN BY BOB HOGAN FROM A PREVIOUS
   FILTER PROGRAM CALLED COB360.CBL WHICH WAS WRITTEN BY AL BLACKINGTON.

2. THE CHANGES MADE TO THE PROGRAM ARE DESIGNED TO MAKE THE FILTER MORE
   USEFUL IN THE CONVERSION OF ALL COBOL PROGRAMS, REGARDLESS OF WHICH
   SOURCE COMPUTER THEY WERE WRITTEN FOR.

3. THE RELEASE OF VERSION 5 COBOL HAS TAKEN CARE OF SOME OF THE PROBLEMS
   WHICH WERE INHERENT IN THE EARLIER FILTERS.

4. ALL MACRO SUBROUTINES FOR DATA MANIPULATION WERE ELIMINATED FROM THE
   FILTER AND THESE ROUTINES ARE NOW DONE IN COBOL.

5. ONE MACRO SUBROUTINE WAS WRITTEN BY DAVE KIARSIS TO HANDLE THE
   WRITING OF THE CONVERTED SOURCE FILE WITHOUT TRAILING SPACES.
   THIS ROUTINE ELIMINATES THE NECESSITY TO RUN THE CONVERTED SOURCE
   PROGRAM THROUGH PIP TO DELETE TRAILING SPACES.

6. THE SELECT CLAUSE NOW ASSIGNS ALL FILES TO DIFFERENT LOGICAL
   NAMES INSTEAD OF ALL BEING ASSIGNED TO DSK. THIS ALLOWS RUNNING THE
   PROGRAM WITH I/O FROM DIFFERENT MEDIA.

7. ALL FILES ARE GIVEN STANDARD LABELS WITH A DIFFERENT VALUE OF
   IDENTIFICATION BASED ON THE SOURCE PROGRAM NAME AND A UNIQUE EXTENSION.

8. ALL "KEY" STATEMENTS ARE LEFT IN SELECT CLAUSES.

9. SEVERAL ADDITIONAL CHECKS FOR INCOMPATIBLE RESERVED WORDS HAVE BEEN
   ADDED. WHERE POSSIBLE THESE HAVE CHANGED TO DECSYSTEM-10 COBOL.

10. THE COMMAND FORMAT IS AS FOLLOWS:

    FN.EXT[PPN]/SWITCH_FN.EXT[PPN]/SWITCH

    THERE ARE NOW FOUR (4) SWITCHES AVAILABLE TO THE FILTER
    PROGRAM. THESE ARE:

    /HELP-----PRINTS A HELP MESSAGE
    /NOLIST---DOES NOT PRODUCE A LIST FILE
    /NOSOUR---DOES NOT PRODUCE A SOURCE FILE
    /SEQUEN---RESEQUENCES SOURCE FILE IN INCREMENTS OF 10


THIS FILTER WILL NOT DO EVERYTHING FOR ALL PROGRAMS, HOWEVER
IT WILL DO MORE THAN THE EXISTING FILTERS AND IT SHOULD MAKE
THE CONVERSION OF MOST COBOL SOURCE PROGRAMS FASTER AND EASIER.