COMTRAN

COMTRAN
Developer	Bob Bemer
First appeared	1957 (1957)
Influenced by
FLOW-MATIC
Influenced
COBOL

COMTRAN (COMmercial TRANslator) is an early programming language developed at IBM. It was intended as the business programming equivalent of the scientific programming language FORTRAN (FORmula TRANslator). It served as one of the forerunners to the COBOL language. Developed by Bob Bemer, in 1957, the language was the first to feature the programming language element known as a picture clause.

Contributions to COBOL

Several elements of COMTRAN were incorporated into COBOL:

• Picture clause.
• Paragraphing: dividing code into paragraphs (with line breaks not significant).
• Paragraph names. Assigning names to paragraphs, and jumps (GO TO's) are to a paragraph name, not to a line number.
• AT END clause on file input operations.
• Figurative constant HIGH-VALUE.
• Passing a numeric value (RETURN-CODE) back to the operating system when the program terminates.

Picture clause

Main article: Picture clause

A picture clause element defines how a particular data item should be formatted, for output. It consists of a string of letters and digits. It is similar to the FORTRAN format specifier seen in the READ and WRITE statements, or the formatting strings seen in more modern languages like C. This became an important part of COBOL.

Sample program

This is a sample COMTRAN program, doing payroll calculations. ^[1]

 01001*PROCEDURE 01002CALL (EMPLOYEE.NUMBER)EMPLOYNO, 01003(BONDEDUCTION)BONDEDUCT, 01004(BONDENOMINATION)BONDENOM, 01005(BONDACCUMULATION)BONDACCUM, 01006(INSURANCE.PREM)INSPREM, 01007(RETIREMENT.PREM)RETPREM, 01008(DEPARTMENT.TOTAL)DPT. 01009START.OPENALLFILES. 01010GET.MASTER.GETMASTER,ATENDDOEND.OF.MASTERS. 01011GET.DETAIL.GETDETAIL,ATENDGOTOEND.OF.DETAILS. 01012COMPARE.EMPLOYEE.NUMBERS.GOTOCOMPUTE.PAYWHENDETAILEMPLOYNO 01013ISEQUALTOMASTEREMPLOYNO,LOW.DETAILWHENDETAIL 01014EMPLOYNOISLESSTHANMASTEREMPLOYNO. 01015HIGH.DETAIL.MOVE 'M'TOMASTERERRORCODE,FILEMASTERIN 01016ERROR.FILE. 01017GETMASTER,ATENDDOEND.OF.MASTERS. 01018GOTOCOMPARE.EMPLOYEE.NUMBERS. 02001LOW.DETAIL.MOVE 'D'TODETAILERRORCODE,FILEDETAILIN 02002ERROR.FILE. 02003GOTOGET.DETAIL. 02004END.OF.MASTERS.IFDETAILEMPLOYNO=HIGH.VALUETHENGOTO 02005END.OF.RUNOTHERWISESETMASTEREMPLOYNO=HIGH.VALUE. 02006END.OF.DETAILS.IFMASTEREMPLOYNO=HIGH.VALUETHENGOTO 02007END.OF.RUNOTHERWISESETDETAILEMPLOYNO=HIGH.VALUE,GO 02008TOCOMPARE.EMPLOYEE.NUMBERS. 02009END.OF.RUN.MOVECORRESPONDINGGRAND.TOTALTOPAYRECORD,FILE 02010PAYRECORD,CLOSEALLFILES. 02011STOP1234. 02012COMPUTE.PAY.IFDETAILHOURSISGREATERTHAN40 THENSETDETAIL 02013GROSS=(DETAILHOURS-40)*MASTERRATE*1.5. 02014SETDETAILGROSS=DETAILGROSS+MASTERRATE*40,DO 02015FICA.ROUTINE,DOWITHHOLDING.TAX.ROUTINE. 02016IFMASTERBONDEDUCTISNOTEQUALTOZEROTHENDO 02017BOND.ROUTINE. 02018DOSEARCHFORINDEX =1(1)12. 02019NET.SETPAYRECORDNETPAY=DETAILGROSS-DETAILFICA-DETAIL 02020WHT-DETAILRETIREMENT-DETAILINSURANCE-DETAIL 02021BONDEDUCT.

References

1. IBM F28-8043 Commercial Translator General Reference Manual, June 1960 (PDF, 8.2 Mo), page 87, via Bit savers.

Further reading

• IBM's Early Computers, by Charles Bashe, Lyle Johnson, John Palmer, and Emerson Pugh, 1986, MIT Press, ISBN   0-262-02225-7.

External links

• Genealogy Programmers Solve Y2K in 1958 Archived 2007-03-04 at the Wayback Machine
• IBM Commercial Translator General Reference Manual (pdf, 8.2M) Page 87.