Re: NOTO (or "no GOTO in FreeForm RPG"): The Empire Strikes Back -- RPG400-L

A hearty Bravo! One of the most important points I got out of this article, and 
it should be, was the discussion about programming skills. Back in the 
trenches, roll out is key, key. Keeping up a high effort level, that's a whole 
other program, especially on a Monday!
Rob
> -----Original Message-----
> From: Reeve [mailto:news@xxxxxxxxxx]
> Sent: Monday, February 16, 2004, 8:24 PM
> To: 'RPG programming on the AS400 / iSeries' <rpg400-l@xxxxxxxxxxxx>
> Subject: NOTO (or "no GOTO in FreeForm RPG"): The Empire Strikes Back
> 
> <snip>
> 
> Huh?  Understanding a SELECT group is not intuitive?!!  This is hardly
> complex stuff here.  If a SELECT group is too difficult for you, you have no
> business being a programmer.
> 
> </snip>
> 
>  
> 
> Huh?  Shoulda worn Nomex today...I'm sure the "you" in "you have no business
> being a programmer" was the editorial "you"!  And what should we say to
> those correspondents making the weekly requests about coloring source code?
> I can't decide if this is vigorous discussion or youthful impatience.
> 
>   
> 
> My customers (many of the most prestigious names in the industry) have
> purchased over 200,000,000 lines of iSeries ERP code I've written myself
> (that number includes quite a bit of reused code, /COPY, etc.).  This is
> about business: my customers appreciate the functionality, style,
> consistency, and stability in my application.  In context (interactive
> programs), my use of GOTO fits a very specific requirement, and I believe
> the customers changing on my code long after I've left the premises
> appreciate its unambiguous style (maintenance programmers are not known for
> having a long attention span).  Business is what I have, and TCO is the
> primary reason organizations buy my application from me (a one-man company)
> and an iSeries to run it.  I stopped writing magazine articles (that you're
> paid for once, usually) in 1980 so I could concentrate on writing code I
> can, and have, sold and installed dozens of times.
> 
>  
> 
> When I was in training for IBM, my final systems project was perfect with
> one exception: the instructor said this System/3 OCL wouldn't work:
> 
>  
> 
> // file name-master1,label-master  ..as a direct file
> 
> // file name-master2,label-master  ..as an indexed file
> 
>  
> 
> I neglected to mention to the instructor that this technique was in
> production at several CCP accounts.  Sales training, you know...John Milton,
> if you're out there...stand corrected and sit down!  (I've wanted to get
> that off my chest for a long time).  How much of what your instructor told
> you have you rejected in the last 15 years?  Plenty, I hope.
> 
>  
> 
> I have had customers (all very nice people) who will look high and low for a
> paper RPG manual to figure out SELECT, and they'll try to figure out what
> that little "c" does in the middle of those I-just-don't-get-them "D"
> specifications.  And when they can't find a source member in QRPGSRC, it's
> because I've deleted it (or at least that's what their voicemails say), and
> then there's a certain amount of angst when the QRPGLESRC member pops up in
> mixed case, with expressions, on their 80-column green screen.  No, I'm not
> referring to you, RPK!
> 
>  
> 
> The reason the iSeries hasn't enjoyed the wild success of other platforms
> isn't because of the use of GOTO's; it's because IBM's midrange offerings
> were later to market than most other players to the GUI/browser environment
> and offered (present tense, too) no integration to common business
> applications available and popular today (Linux doesn't meet both conditions
> yet).  Modern programming constructs are required to support a more
> sophisticated UI, but iSeries purchase decisions are frequently based on
> applications and not on the availability of qualified data structures, etc.
> API's haven't been around forever, gentle reader, and we're much better off
> for having them available.
> 
>  
> 
> Programmers are limited by what IBM provides, and IMHO IBM won the battle
> but lost the war by enhancing the S/36 instead of pricing the AS/400 right,
> developing an effective conversion tool, and dumping the 36 altogether (I've
> stayed 36-free for a career).  In the history of IBM's midrange family (my
> history goes back 29 years), RPG has made real advances not in the last 29
> years but mainly with the advent of the iSeries, and I salute George,
> Barbara, Hans, et al. for their contributions (I can't say it in Python). 
> 
>  
> 
> I don't think I'm tilting at windmills here.  I believe the proper use of
> GOTO reduces deep, complex, error-prone levels of nesting and eliminates the
> requirement for switches, flags, and other non-structural techniques. 
> 
>  
> 
> I see many emotional arguments ("best practice", "Programming 101", "dying
> out") against GOTO.  "Best practice" doesn't mean "only practice" or "right
> way", of course, and I wonder how many other "best practices" go into the
> dust bin.  I suggest the real problem in programming training is that it
> usually teaches coding techniques and a programming language, not
> programming skills.  And I offer the possibility that the problems created
> by GOTO mishmashes can be trumped by the problems arising from the use of
> more complex (not "more elegant") coding structures to control program flow
> (application logic is a distinctly different case), all in the interest of
> worshipping the False Prophet Of Noto.  Programming errors are a fact of
> programming life; the key is minimizing them, and then making them easy to
> identify and fix for the Unknown Programmer In The Future.
> 
>  
> 
> Let's see what Google says about programming "best practices": 
> 
> www-106.ibm.com/developerworks/eserver/articles/hook_duttaC.html?ca=dgr-nxw0
> 2BestC
> 
>  
> 
> First on the list: "Use a source code style that makes the code readable and
> consistent."
> 
> Way, WAY down on the list (around #25): "GOTO should be used sparingly"
> 
>  
> 
> Dijkstra, Rubin, and McConnell have comments regarding GOTO; they're worth
> reading.
> 
>  
> 
> Back in the Dark Ages (apparently when I learned to code), program
> readability was important.  One of the big considerations was keeping a
> meaningful hunk of code on a single page, so excessive page-turning by the
> programmer was eliminated.  Now, we have WDSCi and can flip CRT pages, but I
> have to believe that trying to determine a program's function by flipping
> around, even assuming the programmer is hip enough to use WDSCi's outline,
> is not good.  Obviously I have to brush up on my "best practices"; I'm
> hoping to see "write it so the next programmer will understand it" somewhere
> on the first page.  And then we have the concept of a proper program, with
> one entry point and one exit point (golly, if I don't understand SELECT, how
> can I know this?); depending upon how far you decompose your code, this
> construct could be hard to design properly...or should we design our systems
> to be like PARS?
> 
>  
> 
> The flap over GOTO's is a canard: the real problem is what's NOT used by, or
> understood by, far too many programmers: prototyped calls, procedures,
> embedded SQL, stored procedures, activation groups, BIF's, expressions,
> WDSCi, that funny QC2LE binding directory, basic debit-and-credit
> accounting, and industry knowledge.  All of those features coexist very
> nicely with GOTO!  Besides, it's not the GOTO's, it's those pesky,
> poorly-positioned TAG's that cause the problems.
> 
>  
> 
> There's a lot of ease-of-use and functionality built into my example
> (below), and a careful examination of the GOTO's will show no occurrence of
> the GOTO "deadly embrace"...I hope...
> 
>  
> 
> Tag1:
> 
> Tag2:
> 
> Goto tag1
> 
> Goto tag2   
> 
>  
> 
> ...which is, I believe, the major problem with most uses of GOTO.  An
> extremely useful syntax check could have been a warning of deadly embrace
> GOTO's; I'm highly confident such a feature will be absent from the next
> "Vote for your enhancements" survey from the RPG team.
> 
>  
> 
> Interesting...I just noticed only one TAG per main (non-HELP) panel.  Do I
> get any points for having a high GOTO/TAG ratio?
> 
>  
> 
> Refactoring pieces is easy; it's doing the whole thing that's nasty.  Nomex
> on...
> 
>  
> 
> Tag1:
> 
>             Display format
> 
>                         Display file error
> 
>                                     Do something to recover and to redisplay
> the format
> 
>             If cmd1
> 
>                         Display help
> 
>                                     Do something to recover and to redisplay
> the format
> 
>                         If not valid-command-key goto tag1
> 
>  
> 
> ***These lines are a group
> 
>             When cmd2
> 
>                         Inquiry1
> 
>                         Goto tag1
> 
>             When cmd3
> 
>                         Exit
> 
>             When cmd7
> 
>                         Inquiry2
> 
>                         Goto tag1
> 
>             When cmd12
> 
>                         Goto tag1
> 
>  
> 
>             Application code
> 
>                         When error
> 
>                                     Goto     tag1
> 
>  
> 
> Tag2:
> 
>             Display format
> 
>                         Display file error
> 
>                                     Do something to recover and to redisplay
> the format
> 
>             If cmd1
> 
>                         Display help
> 
>                                     Do something to recover and to redisplay
> the format
> 
>                         If not valid-command-key goto tag2
> 
>  
> 
> ***These lines are a group
> 
>             When cmd2
> 
>                         Inquiry1
> 
>                         Goto tag2
> 
>             When cmd3
> 
>                         Exit
> 
>             When cmd5
> 
>                         Inquiry3
> 
>             When cmd7
> 
>                         Inquiry2
> 
>                         Goto tag2
> 
>             When cmd12
> 
>                         Goto tag1
> 
>  
> 
>             Application code
> 
>                         When error
> 
>                                     Goto tag2
> 
>  
> 
> ...and so on...
> 
>  
> 
> Considerations:
> 
> The HELP panel is not required to use command keys, which is why it's coded
> outside the implicit SELECT.  The command keys are accessible from the main
> panel or from the help panel.
> 
>  
> 
> There are multiple panels in every application
> 
>  
> 
> Each panel has a combination of standard and unique command key options.
> 
>  
> 
> There may be a shortcut on the main panel to jump directly to other panels.
> 
>  
> 
> This is a refactoring exercise; no alteration or reduction of user function
> is allowed.  If there is a better path, I will take it.  But "better" is an
> emotional response too!
> 
>  
> 
> --------------------------
> 
> I've failed to mention the self-documenting nature of the GOTO/TAG
> construct, possibly because I've failed to take advantage of that useful
> feature myself.  I'm paying too much attention to style; all my tags are
> named TAGnnn.
> 
>  
> 
> At this point, I have to GOTO the sandbox and then GOTO dinner.  Or is it
> DOU *FULL and DOW NOT *HUNGRY?
> 
>  
> 
> -Reeve
> 
>  
> 
>  
> 
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