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openedgeprogress-4gllanguage-concepts

What's the idea behing W-, P- and I-files?

I'm working with appBuilder and procedure editor in Progress Release 11.6.

As mentioned in some previous questions, regularly I'm having problems with the appBuilder, not wanting to open files, corrupting them (deleting parts of source code), ..., one of the reasons now seems to be the limit that a procedure cannot exceed 32K, comments included.

At first I thought "Are we back in the stone age?", pardon my reaction.

But now I start thinking that we are completely abusing the whole concept, therefore I'd like to show my view on W-, P- and I-files, please confirm (or correct):

W-files are meant only to contain GUI definitions, like a form with some frames, buttons, fill-in fields, ..., any real programming needs to be done in P-files.
P-files contain the real intelligence: there the procedures and functions are elaborated, that can be used by the rest of the P-files, or finally by the W-files.
I-files are just there to include general behaviour.

Let me give you an example:

W-file:

DEFINE VARIABLE combo_information VIEW-AS COMBOBOX /* with some information on the content, if this is static */
...
ON CHOOSE OF combo_information DO:
  RUN very_large_procedure.
END.
...
{about.i} /* see here-after */
...

P-file:

PROCEDURE very_large_procedure:
DO /* a lot */
END.

I-file (about.i):

/* Describes the help-about menu item */

While working like this (only putting the GUI-related things in the W-file and let the "real" programming be done in the P-files), the mentioned 32K limit will never be reached. In top of that, adding a procedure can be done easily, the appBuilder will not delete it as the appBuilder won't ever open the P-file.

Is my view correct (and what about the I-files)?
In case yes: one technical question: how can I launch a procedure from a P-file inside a W-file? (Obviously, the mentioned example can't work as in the W-file I did not mention where to look for the very_large_procedure)

Solution

  • The naming is arbitrary and you may occasionally find other extensions being used. Having said that:

    "W" is for "window", it is supposed to contain code that is related to making a GUI work. It is very often abused to contain any sort of code. It is usually abused in that way by people who learned to code on the app builder or who have never coded on anything but Windows.

    "P" is for "Progress" and retconned to "Procedure". It was the standard back in the old days prior to the appearance of Windows GUI code. Any "headless" code or character mode code would typically go into a dot-p file.

    "I" is for "include". This is a very old school way to create reusable code snippets and common "header files". Include files are commonly parameterized. Potentially with either named or positional arguments.

    Another major extension is ".cls" files. These are for OO4GL classes (OpenEdge 10 and above).

    Launching procedures is acheived by running them:

    RUN myproc.p.

    or

    RUN guiproc.w.

    Or, if by "launch", you mean "start a session" then you use the "-p procedureName" startup parameter along with prowin32.exe or prowin.exe for Windows GUI code or _progres.exe for batch or character code.