Re: PSPP conference call notes.

[John Darrington]

On Thu, Jun 01, 2006 at 12:15:49PM -0700, Ben Pfaff wrote:
     > So it seems that the next release will feature the GUI.  Thinking
     > about it last night, I'm of the opinion that, in its first public
     > appearance, it should favour stability rather than features.
     >
     > So I propose that it be released as a "System/Portable file editor".
     > Getting it to actually run procedures is another ball game, which can
     > start after the next release.
     
     This is OK by me.
     
     > On this basis, I think that the end of 2006 is a reasonable release
     > date to aim for.
     
     Well, OK.  At first when I saw this I thought that it sounded
     pretty far off, but really it's probably a realistic goal.

This is my first attempt at writing a non-trivial GUI program, and I'm
still learning.  One thing I'm finding is that it's almost impossible
to automate testing in the way that we do the rest of PSPP.
Consequently, it's necessary to think very carefully before inserting
new code.  I can always use feedback from people who discover problems.
     
     > 2. Something to build the output tables.  A glade type application
     >    springs to mind.  But it would be a lot of work to do.
     
     I've also thought about this a bit.  It honestly hadn't occurred
     to me that an interactive application would be a good way to do
     it.  My tendency is always to think about inventing languages to
     describe things.

In general, I tend to think the same way.  However in this instance, I
think that graphical tool may be appropriate for designing graphic
objects (ie tables).  
     
     Here are some of the things that I took away from the
     conversation, in addition to what you say:
     
     - Need casefile bookmarking/cloning.  Should be easy; I'll take
       care of it soon.
     
       This will enable RANK.

It will also enable (I hope) integration of casefiles into the GUI.
There's a fundamental problem here:  The GUI needs to scroll through
the cases.  Scrolling forwards is not a problem.  Scrolling backwards
is something that casefiles don't allow.  My idea is to cache a small
number of cases (about twice the number that fits in the window) which
allows for small magnetude scrolling.  Scrolling back through larger
offsets is where the bookmark would come into play.
     
     - Should add log file support and support for sending errors to
       the listing file.  Both should be easy now.

But we need to consider the i18n issues involved.
     
     - Should add a command to change the width or type of variables,
       to enable the GUI to do these things.

Changing the type isn't a problem.  Changes to the width can be, if it
means a corresponing change to the size of the cases.
     
     - Need some work to make Mac OS system files work.  John has an
       example system file (can you file a bug report and attach it?).


Looking at the problem again, I'm not sure that this isn't a more
general issue with the way that sys-file-reader handles record 7(11)
--- it so happens that all of my example files which have this record
have been created with the Mac.  I'll try to get access to a Windoze
machine next week to investigate a bit further.  In the mean time I've
added code to make PSPP more tolerant of measure/alignment parameters
which don't seem to have valid values.


J'

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