[uf-new] Currency brainstorming

[Guillaume Lebleu]

Andy Mabbett wrote:
> In message <46FD2AD0.8080606 at brixlogic.com>, Guillaume Lebleu 
> <gl at brixlogic.com> writes
>
>> IMO, we must conceptually distinguish the notion of *money amount* 
>> and the notion of *price*. A money amount is an amount of a given 
>> number of units of currency. A price is an equivalence relationship 
>> typically between a money amount and another amount in any 
>> measurement unit. Some prices are expressed without using currencies. 
>> Some prices are prices of one currency in another one (as in 1 euro = 
>> 1.41 dollars).
>>
>> The amount+unit is not a relation and does not change over time, and 
>> does not have to be dated.
>>
>> A price does change over time, and should be dated.
>>
>> In Andy's example above, the date is not a property of the "hmoney" 
>> class, but of a TBD "hprice" class.
>
> I don't see any advantage in making such a distinction, nor any 
> problem in not doing so,
>
> Perhaps you could enlighten me, with real-world published examples?
>
The advantage is less confusion.

If I'm a publisher and I need to mark up POSH the following "The Euro 
stood at 1.41 US dollars in September 2007",

We don't want publishers to mark up:

"The Euro stood at
<span class="money">1.41
    <span class="currency" title="USD">US dollars</span>
     in
    <span class="date">September 2007</span>
</span>".

Of course that is, unless you think the following is not better a better 
reflection of the intent of the author:

"<span class="exchangerate">
    <span class="currency" title="EUR">The Euro</span>
     stood at
    <span class="price">
        <span class="hmoney">
            <span class="value">1.41</span>
            <span class="currency" title="USD">US dollars</span>
        </span> in
        <span class="date">September 2007</span>
    </span>
</span>"

(date property of price)

or possibly:

"<span class="exchangerate">
    <span class="currency" title="EUR">The Euro</span>
     stood at
    <span class="price">
        <span class="hmoney">
            <span class="value">1.41</span>
            <span class="currency" title="USD">US dollars</span>
        </span> in
    </span>
    <span class="date">September 2007</span>
</span>"

(date property of exchangerate)

I looked at most of the historic prices examples you presented: 
http://microformats.org/wiki/currency-examples#Historic_prices

For what I can see, in most of these examples, the datetime near a money 
amount usually related to the relationship between a currency and 
another, or a currency and a commodity, not to the currency itself. When 
a datetime is nearby, it usually refers to the datetime of the posting, 
or of the general context in which the events described must be taken.

In other words, in most cases and example shown, the datetime of the 
money amount is implicit, inferred from the context, not explicit. 
Theses date time should not be marked up as part of the money amount, 
but as part of a "price" class, "article" class, or "exchangerate" class.

A datetime explicitly linked to a money amount is much rarer. The only 
case I can think of where a date is directly related to a currency is in 
"Damage in Bay County, Florida alone totaled US$50 million (1975 
dollars)" http://en.wikipedia.org/wiki/Hurricane_Eloise.

In this example, you are correct, we should have:

"Florida alone totaled <span class="hmoney"><span class="currency" 
title="USD">US$</span><span class="value" title="50000000">50 
million</span> <span class="date">(1975 dollars)</span></span>"

So, while I can find an example that support your feature suggestion, I 
believe the above example where the date of the currency is not implicit 
is rare enough to be left aside for now for the purpose of moving this 
proposal forward and avoiding confusion within publishers.

Guillaume