[sugar] gtk experiment for an spreadsheet activity

[Tomeu Vizoso]

Hi all,

what can be done during a weekend without net access but with a copy of
the pygtk tutorial? An spreadsheet!

http://dev.laptop.org/~tomeu/Count-1.xo
http://dev.laptop.org/~tomeu/count-screenshot.png

Well, not quite.

This can be seen more accurately as an experiment to see until which
point the gtk.TreeView widget can carry us. These are the things that I
haven't found how to do with the current gtk.TreeView:

- Row headers.
- Non-fixed number of columns.
- Alignment of values inside the cells.
- Automatically add rows as the user scrolls down.
- Support big datasets efficiently.
- A more standard way of starting cell edits.

To fix these would probably take forking the upstream gtk.TreeView
inside the activity bundle.

This is NOT an attempt to replace the current efforts of porting
SocialCalc and Gnumeric to Sugar. While these projects aim for full
featured spreadsheets, gtk.TreeView will probably be only enough for a
very limited spreadsheet that only support the most basic functionality,
mainly manipulation of tabulated data and some simple functions.

The basic infrastructure for supporting functions is there, but a parser
and an evaluator still need to be implemented.

I hope this can be useful:

- as an example of a basic python activity, perhaps of some use to the
sugarizing of SocialCalc and Gnumeric,
- as a possible placeholder until we have a better spreadsheet if nor
SocialCalc nor Gnumeric can be present in the Update.2 milestone.

Cheers,

Tomeu