PODA PODA PODA PODA PODA PODA
One of the first things that are discussed when you did
(if you did) the Action Diagramming course for 2E is PODA.
PODA is an approach to effective function design.
- P is for parameters and the interface.
- O is for options (Function Options)
- D is for device design (Screen/Print)
- A is for action diagram.
The concept being that these all influence the function
and getting them correct will mean you’ll write less code and won’t be
wrestling with the template (prototypes/patterns).
Bare this in mind for the rest of the blog post.
I was at work the other day and was maintaining some code
where once again I could be heard saying, “Whoever wrote this should be shot!". It’s my preferred (go to) phrase when I see
badly written/designed/architect-ed code.
Anyhow in this instance the code was quite simple and
generic so I can share it here.
The reason for my comment above was why is this code
inside a subroutine called Subroutine?
The actual function ‘Perform Substitution’ was itself and EIF (Execute Internal
Function).
I thought to myself, it is okay someone probably wanted
to be able to *QUIT from one of the case blocks below….. NO!!!
Hmmmm.......Perhaps someone was being a dunce!
Anyhow, depending on you model default and EIF can be
generated as either inline code or as a subroutine. I am thinking that this code might be quite
old or that someone simply doesn’t understand how the code is generated in 2E.
(Probably the later).
Most of you know that you can share subroutines and
reduce code bloat using the ‘Share subroutine’ option. And EIF also has an additional option called ‘Generate
as subroutine’.
In the instance above we could have achieved the same
result with omitting the sequence block and simply setting the value.
Let’s explore the generated code for a much simpler
example. I have an EEF (Execute External
Function) calling and EIF. The EEF is
setting the local context for LCL.*JOB DATE to JOB.*Job Date and then calls the
EIF which in turn set the WRK.*Job Date to JOB.*Job Date.
With ‘Generate as subroutine’ set to No we get inline
code. (See below).
Taking the original example (see top), if I put the internal
code inside a Sequence block I’d get a subroutine.
See code mock up below.
So although this code looks a little neater, it still isn’t
perfect.
Setting the option Generate as subroutine’ to Yes
generates slightly difference code.
Overall, in this instance it didn’t matter too much as
there were NO *QUIT’s to worry about and the routines weren’t (or couldn’t) be
shared etc. But it does highlight that
following PODA can make your programmer life easier, not to mention mine..... as I mop up after you....
Thanks for reading.
Lee.
