Re: [office-formula] Grouping functions and capabilities

["David A. Wheeler" <dwheeler@dwheeler.com>]

I said:
> > The old "OpenFormula" had level 1, 2, etc., and we
> > agreed that this was too constraining.  Interestingly enough,
> > the folks who were most concerned (wikiCalc) has since found
> > that it wasn't hard to add all the "level 1" functions, and
> > of course that aids portability.
> > 
> > Thus, for a start, here's what I propose:
> > * For every function, instead of saying "level X", simply
> >    give the function name as its (lowest-level) group.  If
> >    some capabilities are at a higher level (not everyone needs
> >    to support them), then append _2, _3, etc.
> > * Group the functions logically, and predefine a few levels
> >    in them the same way.
> > * Define something like "levels" at the end.

Rob Weir said:
> I'm not following.  Can you give a couple of examples?

Okay, how's this:
* Function "AND" is a function, and most of its requirements
   are assigned to the "AND_1" group.  For an implementation
   to meet the "AND_1" group requirements, it has to implement
   all of its requirements (including all the test cases identified for it).
* A "_LOGICAL_1" group is defined as the group (of groups):
   AND_1 + OR_1 + NOT_1 + ...
   To meet the _LOGICAL_1 requirements, you have to meet all of them.
* A _LEVEL_1 group is defined as the group:
   _LOGICAL_1 + _FINANCIAL_1 + ...
   So if you want to acquire a spreadsheet that meets "_LEVEL_1"
   requirements, you can easily state that requirement.  If you
   really only need the _LOGICAL_1 functions, you can state that too.
   A _LEVEL_2, etc., could be defined the same way.

This is more flexible that the old "single number" system, at the cost
of more complexity in the spec.  All the tables saying "Level" would
need to be changed to say "Group", and all the level numbers would
need to be changed to text values.

--- David A. Wheeler