Re: Benefits of Sub-procedures

[rob@xxxxxxxxx]

Hans you might have a point there about some programming.

"Had" a programmer here who would not take the time to teach himself 
Query.  Turned out he couldn't write anything more complicated than a 
report that could be generated by Query.

Rob Berendt
-- 
"They that can give up essential liberty to obtain a little temporary 
safety deserve neither liberty nor safety." 
Benjamin Franklin 




Hans Boldt <boldt@xxxxxxxxxx> 
Sent by: rpg400-l-bounces@xxxxxxxxxxxx
10/24/2003 08:19 AM
Please respond to
RPG programming on the AS400 / iSeries <rpg400-l@xxxxxxxxxxxx>


To
rpg400-l@xxxxxxxxxxxx
cc

Subject
Re: Benefits of Sub-procedures






jt wrote:
> ...  Similarly I would
> ask, why would anyone want to code this:
> 
> parms.transNo = %editc((%dec(transNo:%size(transNo):0) + 1):'X');
> 
> in order to increment a transaction number...???  I ask this seriously: 
Why
> do you need "rocket science" to add 1 to an alpha transaction number??
> Iirc, seems like only one person on this list even came up with an
> /alternative/, a simple data structure.  I guess because if it ain't
> "modern", it ain't cool...

That's really the wrong question. A more appropriate one is this: 
Why would anyone want to implement a transaction /number/ as an 
alpha string? Many other languages with strong type checking require 
similar machinations. For example, in Python, you might code 
something contrived like:

n='%.*d'%(len(n),int(n)+1)

(That is, convert the number string to an int, add one. Then format 
it as a numeric padded to the length of the original string.)

If you want looser interpretations of numeric and character types, 
you could go to Perl or Rexx, which allow mixed character and 
numeric operations. But then you'd still have the issue of keeping 
leading zeros.

A more appropriate solution for this problem (in any language) would 
involve a procedure (remember procedures?) which returns the next 
available transaction number as a string. Then, the users of the 
procedure are spared the gory details of the actual implementation.

Likewise, a Python programmer would (or should) never code that 
crufty statement above. A more typical coding practice would be to 
code a "transaction number" class. Getting a new transaction number 
would then just require a statement like "transnum=tn.next()". The 
details of how the transaction number are implemented belong in the 
class, and not in the calling code.

For example, in Python you might code something like:

class Counter:
     def __init__(self, start=0, size=5):
         self.count = start
         self.size = size
     def next(self):
         self.count += 1
         return '%.*d'%(self.size,self.count)

c = Counter(start=234,size=7)
print c.next()
print c.next()
print c.next()
print c.next()

(Sorry for posting Python code in an RPG list. But it's easier to 
whip up a Python example to illustrate my point. Don't sweat the 
details - just think of it as "executable pseudo-code".)

> 
> Businesses are not primarily about coddling people who care a /whole/ 
lot
> more about looking cool than they do producing a solution, (one that 
works
> like the Energizer Bunny (tm, I sure...;-)), and producing it on a
> reasonable timeline (ie, cost).  At least, in my experience.
> 

Exactly. And that's why programmers in practically all other 
programming languages use procedures extensively.

This gets back to my theory that a large number of programmers 
really don't want programming to be easier, and I suspect that's 
true especially among RPG programmers. Are more modern (that is, 
1970's or later) programming techniques like procedures considered 
too "cool", and thus suspect? Is RPG programming supposed to be 
hard? Are RPG programmers who make programming look hard considered 
more capable than programmers who make it look easy?

Cheers! Hans


_______________________________________________
This is the RPG programming on the AS400 / iSeries (RPG400-L) mailing list
To post a message email: RPG400-L@xxxxxxxxxxxx
To subscribe, unsubscribe, or change list options,
visit: http://lists.midrange.com/mailman/listinfo/rpg400-l
or email: RPG400-L-request@xxxxxxxxxxxx
Before posting, please take a moment to review the archives
at http://archive.midrange.com/rpg400-l.