Re: Directory restructuring

[John Darrington]

The first-in-first-out model is certainly appropriate for errors
caused by parsing syntax, where the concern is to provide information
which will enable the user to fix the syntax.   But I'm not sure if
it's correct for other types of errors/messages.  I note that the gtk+
library uses a stack for its status
bar. http://developer.gnome.org/doc/API/2.0/gtk/GtkStatusbar.html  
They obviously believe that the most recent message should be
displayed first.

Consider what might happen if and when we implement pspp as a client
server model.   If the server crashes, then the client might
experience dozens of errors (eg catagorical variable equals SYSMIS),
but the loss of communication with the back-end might be not be
detected until several seconds later.  In this scenario, the loss of
communication is the most useful message, whereas data having strange
values is incidental.

Having said that, it seems that having msg() push a value into some
sort of structure is probably a good idea.  Exactly what sort of
structure that should be, and how items can be extracted from it can
probably be changed at a later date.

J'



On Sun, Feb 05, 2006 at 07:45:25AM -0800, Ben Pfaff wrote:
     
     I'm not sure that I explained properly, based on your reaction.
     A priority queue wouldn't be the right thing to do in general, in
     my opinion, because it would cause the messages to be reordered.
     If I have a warning on line 10, then an error on line 11, I want
     to see the warning first, not the error.
     
     I expect that in "normal" operation, messages would queue up for
     the entire execution of a command, then back in the main command
     loop we'd print them out in order.  In the text UI, I expect that
     would be in main() as the code is currently organized.  In the
     graphical UI, we'd be able to avoid the problem of an enormous
     number of dialogs easily because we'd have the whole list of
     messages at once.  Instead of putting up 250 dialogs, we could
     just display a single dialog with a scrolling list of all the
     messages for a command; or just display the first message; or
     only display the messages with priority higher than "warning"; or
     just the most severe, as you say.
     
     On another note, some IDEs use a scrolling pane to display error
     messages.  I don't know if that's appropriate for PSPP.

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