Bill, well of course my code is much more complicated than my little example. I have lots of "if" blocks within my block of code. And some of those "if" blocks will do a "GOTO GetCursor" to fetch the next row. There is also a possibility that there could be a fatal error that would cause it to go to EndCursor, but I don't have one of those. So do you think there's a memory leak when there's a "goto" within an "if"? I know we've had many threads on this before. It's well known that you do NOT do a GoTo within a while loop that takes you to a label outside the while loop, but I thought we were pretty safe when the goto is within an "if"
Karen -----Original Message----- From: Bill Downall <[email protected]> To: RBASE-L Mailing List <[email protected]> Sent: Fri, Mar 21, 2014 8:32 am Subject: [RBASE-L] - Re: Thanks to someone for the code! Tony is right, that the IF/GOTO constructs can be dangerous, but in this case, Karen is using a "Structured GOTO" to get around limitations of WHILE loops. If you look at Label EndCursor, you will see that there is a GOTO GetCursor just before it. There is still only one way in the code to get to the WRITE 'I am done!' statement. IF/GOTO becomes dangerous and hard to maintain when you have multiple ways to get to a block of code. Bill On Fri, Mar 21, 2014 at 9:14 AM, Dennis McGrath <[email protected]> wrote: Also note, RStyle recognized two special comments --indent and --outdent to make goto loops format in a readable structure. It even enforces that they be paired. As far as RStyle is concerned, they are part of the code structure. DROP CURSOR C1 DECLARE C1 CURSOR FOR SELECT ....... blah blah blah OPEN C1 LABEL GetCursor --indent FETCH C1 INTO ..... blah blah blah IF SQLCODE = 100 THEN GOTO EndCursor ENDIF -- do all your processing here GOTO GetCursor --outdent LABEL EndCursor WRITE 'I AM DONE!' RETURN Dennis McGrath Software Developer QMI Security Solutions 1661 Glenlake Ave Itasca IL 60143 630-980-8461 [email protected] From: [email protected] [mailto:[email protected]] On Behalf Of Dennis McGrath Sent: Friday, March 21, 2014 7:59 AM To: RBASE-L Mailing List Subject: [RBASE-L] - Re: Thanks to someone for the code! Tony, Large while loops tend to be difficult to maintain as it is very easy to write something that will crash the loop. Also, I have had while loops that absolutely refused to trace making debugging impossible. Using the GOTO loop method results in code that may run a little slower, but is easier to maintain and not as fragile. I use while loops for small tasks that iterate a great many times, and are not likely to change over time. Otherwise, my time is better spent writing code that is less time intensive to debug and maintain. I’m sure there are those folks who will violently disagree with me, and that is OK too. Dennis McGrath Software Developer QMI Security Solutions 1661 Glenlake Ave Itasca IL 60143 630-980-8461 [email protected] From: [email protected] [mailto:[email protected]] On Behalf Of Tony IJntema Sent: Friday, March 21, 2014 6:40 AM To: RBASE-L Mailing List Subject: [RBASE-L] - Re: Thanks to someone for the code! Karen, Maybe not relevant, but why don’t you use the while-endwhile construction. If statements are handy, but also a little dangerous 10 if statements in a program will result in 1024 paths through your program Tony DROP CURSOR c1 DECLARE c1 CURSOR FOR SELECT ....... blah blah blah OPEN c1 FETCH c1 INTO ..... blah blah blah while SQLCODE <> 100 THEN -- do all your processing here FETCH c1 INTO ..... blah blah blah endwhile WRITE 'I AM DONE!' From: [email protected] [mailto:[email protected]] On Behalf Of Karen Tellef Sent: donderdag 20 maart 2014 23:18 To: RBASE-L Mailing List Subject: [RBASE-L] - Re: Thanks to someone for the code! Well then, I'm guessing it was either Dennis or Alastair! Or both! Karen -----Original Message----- From: Alastair Burr <[email protected]> To: RBASE-L Mailing List <[email protected]> Sent: Thu, Mar 20, 2014 2:21 pm Subject: [RBASE-L] - RE: Thanks to someone for the code! And I, for one, have been using it for many of those years. Cheers, Dennis, Regards, Alastair. From: Dennis McGrath Sent: Thursday, March 20, 2014 7:01 PM To: RBASE-L Mailing List Subject: [RBASE-L] - RE: Thanks to someone for the code! Perhaps someone else shared that with you but I’m been preaching that style for mucho many years. Dennis McGrath Software Developer QMI Security Solutions 1661 Glenlake Ave Itasca IL 60143 630-980-8461 [email protected] From: [email protected] [mailto:[email protected]] On Behalf Of Karen Tellef Sent: Thursday, March 20, 2014 1:52 PM To: RBASE-L Mailing List Subject: [RBASE-L] - Thanks to someone for the code! Probably a year ago I asked for recommendations of how to use alternative code for a cursor that had to go through 50,000 rows of data, run hundreds of lines of code per record, and would periodically lock up. I got a couple examples, and I picked this one as being the easiest to follow, the simplest and best of all, IT WORKS! I forgot who gave it to me, but thank you! And perhaps this will help someone else. Karen DROP CURSOR c1 DECLARE c1 CURSOR FOR SELECT ....... blah blah blah OPEN c1 LABEL GetCursor FETCH c1 INTO ..... blah blah blah IF SQLCODE = 100 THEN GOTO EndCursor ENDIF -- do all your processing here GOTO GetCursor LABEL EndCursor WRITE 'I AM DONE!' RETURN
