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 >
