[uf-discuss] Re: Currency + Unit of measurement (Was: Currency+Product)

[Guillaume Lebleu]

I don't think Lorenzo is talking of: *currency amount per item/product* 
as your title and example imply (that, I agree, is a non-starter)

but of *currency amount per unit of measurement* (which is widely used - 
see for instance: http://www.bloomberg.com/energy/, although not in the 
context of a house/product/job in which case the unit is obvious).

In "$25 per barrel" or in "25 ($/bbl)", I think you would agree that 
knowing that the barrel is the unit of measurement is very significant, 
and even though knowing that "$" means USD dollars, overlooking that it 
is a price per barrel would lead to a big mistake.

I think Lorenzo is furthermore suggesting that a currency is just 
another unit. I agree conceptually that it is, but in practice, standard 
bodies (that I know of) have traditionally separated currency amounts 
from other measures. For instance, I took a look at the UNECE 
recommended codes for units of measurement (reused by some industry 
standards), available at: 
http://www.unece.org/cefact/codesfortrade/codes_index.htm. 
http://www.unece.org/cefact/recommendations/rec20/rec20.zip. They indeed 
have the barrel (US) as a well-known unit, but as I mentioned UNECE does 
not include currencies in their list of units of measurement.

Which leads me to my updated code examples.

<span class="price"><abbr class="currency" title="USD">$</abbv><span 
class="value">25</span> <span class="unit" title="BLL">per 
barrel</span></span>

<span class="price"><span class="value">25</span> <abbr class="currency" 
title="USD">$</abbv><abbr class="unit" title="BLL">/bbl</abbr></span></span>

<span class="price">On <abbr class="datetime" 
title="1998-03-12T08:30:00-05:00">August 1</abbr>, the US Dollar still 
stood at <span class="value">643 <abbr class="currency" 
title="DEM">Marks</abbr></span> to the <span class="unit currency" 
title="USD">Dollar</span>.</span>

The following rules should be used:

    * If "value" is not present, then value = 1.
    * "unit" is optional

By the way, I haven't found any measurement microformat on the wiki, so 
maybe we could do the currency+measurement at the same time.

Let me know what you think.

Guillaume