I generally get by with control structures like case (select/when), if/elsif/when, iterate and leave, but I unashamedly use GOTO, when it is the cleanest way to do something; I refuse to avoid a useful construct just because it is not politically correct. In the case of COBOL, I consider the out of line PERFORM to be far more dangerous. I have a similar issue with REXX; it does not have lexical scope, and you can fall into a procedure.
-- Shmuel (Seymour J.) Metz http://mason.gmu.edu/~smetz3 ________________________________________ From: IBM Mainframe Discussion List [IBM-MAIN@LISTSERV.UA.EDU] on behalf of Bernd Oppolzer [bernd.oppol...@t-online.de] Sent: Sunday, June 7, 2020 6:17 AM To: IBM-MAIN@LISTSERV.UA.EDU Subject: Goto Statements (was: COBOL Question) Thank you very much for the link to that article; I did not know that before. When I started to work on the Stanford Pascal compiler in 2011, it had about 20 to 30 labels and Gotos (6000 lines of source code). http://secure-web.cisco.com/1pX2kW19qrUp9yyoP4cfhRRs2ehNXyOiR8ZzrLZPfjVUIuBM5B0cu5ExeRn-gVhTqtsFmQqRCeX1kWt8GVLJyqBetd-We06QY6gkbVWv3QC1o-NEVdaqRH6t2DH39gZvw0-3Jihs-F5wMJmmJUpgr5TRe-YayUTWUwX8Ei1zyTXm3YUVjbqPmkwLafqSKfBfd7dffvaXZkRLue6QQlmtfeaQ2d1GitnaBXNkNX9uaLzv2H5RvX0D-L61XkawFX-Eek9LsXAx0ycMXFpGNImgy5z9eMSon1P95x3V9wTqj1Pw6li8X2jwgFaZf1K_OkHNP4J_e51OIlCSPmnr61YIXw_-N0KKbOmQDuxiLobG46E7__kPTDeUP6oVHTPSdfvi8bQ6hhgm0MAe1y0jWiSnvezjXncFaNcNhThLUdm5bv1vkXAAvMM89ntcCkUAiNb44/http%3A%2F%2Fbernd-oppolzer.de%2Fjob9.htm In the meantime, I omitted most of them, but this was only possible, after I added CONTINUE and BREAK (for all three types of loops) and RETURN (to do early returns from procedures), which are not present in Standard Pascal. http://secure-web.cisco.com/1Km_bU1ZhlXrKXvTgabvFbHyaYXnzrcmk29Sl8AEjRAtYm4DFVcOJwHT6UIto3Tv4KffE0e3UQGWhHuGzdbAd-m2WCw4XJOZavBvuPWSV9525c1v_HDcAvHJIHIA6np8gqeDNP9bJFESQpyaSyQivd7HdNVnZTzfPKzWC2Bcv82b4oS_eTA6_H7fYXeBcHDP76oBOMOyB-kYDewa6mzanpF2bWJDRsXBYrQsW5qSE7Fk3sggZqGbEAYcJlLHNrF8IZSg3UmLFP_nCC5K9ftu_qXhfj-mM8dDUC52sS0YD1lON2dpIK7GgMzQ9WudkLKf-Z43IOBnRltKuxHzXUiTetyx7siAqIytTDFJ5C-29z1pojvBmeRIHtb0-K74gMS83Q9i2y7Sj7nPydr_ou22wlo62sHVFJ4yS9RU4NANqxMEEbsrJuWL_ZM1qQjZPEuRa/http%3A%2F%2Fbernd-oppolzer.de%2Fjob9i004.htm The compiler now has 22000 lines of code (much more function than the 2011 version), but much less gotos. Back to Cobol: IMO, many of the observations of the 1960s are still valid for today's modern COBOL: if you use (for example) inline PERFORM and all the possibilities to do structured programming in COBOL and try to reduce the use of Gotos to an absolute minimum (for example: leave the program in case of catastrophic errors), then your programs will be easier to read and maintain; at least that's what I am experiencing. BTW: I added so much function to the New Stanford Pascal compiler in the years since 2011 (and I ported it to Windows and Linux etc.), that I recently was able to use it to write a COBOL source code formatter using this compiler, which is very helpful when doing maintenance work on (large old) COBOL programs. I am thinking about enhancing this source code formatter (which does COBOL parsing to some degree) to get meta information out of the COBOL source code, for example file usage or to throw warnings about strange logic constructs - much the same way as my PL/1 tool from 2007 did it (this was written in C). If someone is interested, I will share the Pascal source of the COBOL source code formatter ... contact me offlline. But you will need the New Stanford Compiler to use it (available from GitHub and from the WebSite above). Kind regards Bernd Am 07.06.2020 um 02:26 schrieb Seymour J Metz: > https://secure-web.cisco.com/1Ly5ugowEV6ot4gbUyw07wld8pVo5RD7yYuLNdHEOf-3il63S7RNh5Uhz3z3qoKCTFZWHjCdAd9NWtRND2NeuvtUodK8xswKDI8qCbark0s6SJ5nXm7-R2ftSd_nYVROosKE8L-PHT1wEeBiCnX_EoOBsN2JcXxfXFq_MNEEfAfs5I_hk6jaQfOdPfRC6_TLwm_g1xb0iM3ICYM0c8XPwUqrA4rLqXyfU-rIz4Dp8LJp_b5--XwmHIh5kl8_oQTbAGn4lksD2k0ehk9-HzYrQGjendQbb39rTwPrLGGng14e9Sx46KhwhyhYMz-stXs2kjIore_VyCD4j1FFWmlNBTVSYtOHijv6gCOsLEv9maQADfq2W7D_-_-XYWu4mAPz3Wu3h15kosqbDyPRuDf-xcCtA_dJ3oB55h5QETpelVe2_CuvHD-y2_nREcy5rpp4t/https%3A%2F%2Fwww.cs.sjsu.edu%2F%7Emak%2FCS185C%2FKnuthStructuredProgrammingGoTo.pdf > > > -- > Shmuel (Seymour J.) Metz > http://mason.gmu.edu/~smetz3 ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
