Re: [office-comment] Re: Unit system tracking

[Alex Hudson <home@alexhudson.com>]

Hey David,

On Mon, 2007-06-11 at 14:13 -0400, David A. Wheeler wrote:
> We discussed adding units of measure at today's OpenDocument
> teleconference.  Certainly, automated tracking/conversion of units of
> measure can be very valuable.
> 
> But I think most people view this capability as out-of-scope for this
> round.  The formula charter specifically says in point 6: "It must be
> friendly to conversions from and to existing office application
> spreadsheet formula languages."  Trying to add full automated
> conversions is a MAJOR change that would permeate any formula
> language.  Even +,-,*,/, and ^ would have to be modified to track
> units, and every value would now be a tuple of (value, units).

I think that's a bit of a hostage to fortune: essentially, we're talking
about typed data (in CS-speak), and if the other side isn't typed then
automated conversion into the typed format is obviously impossible. But,
I don't see why you'd attempt that - e.g., ODF doesn't ask people to
up-convert tables into page columns when they're used for layout. The
typed stuff is extra mojo on top. While it doesn't aid conversion, I
don't see that it hampers it.

I probably mostly agree with the end decision, but I think this should
be kept on the radar. Stuff like <number:currency-style> seems to me a
horrible mishmash of presentation and meta-data, and this type of
proposal could sort this out (i.e., separate the "this data is currency
in USD" from the "format USD values in blue with a $ on the front").

If correctly used (ha ha ha!), this would also be a significant user
convenience, I can think of two big use cases:

      * detection of user error - e.g., "time multiplied by time makes
        no sense!"
      * being able to get away from formulas to do conversions - e.g.,
        no more "(A1/12) is the rental value per month", so when A1
        changes from being an annual value to a six-monthly value, the
        calculation still works

Cheers,

Alex.