Re: [Cbor] Proposal for Currency and Money Amount

[Richter, Jörg <[e-mail]>]

> Should this support non-decimal currency amounts?
> As far as I can tell, the only currently in use non-decimal currency is
> the Mauritania's ouguiya (ISO 4217: MRU & 929) which uses 1 ouguiya = 5 khoums
> ...
> (I suppose the simplest solution to allowing non-decimal currencies would be
> to make the array 2 or more elements.  The currency code tells the consumer
> how to render the encoded values.)

I would be very surprised if software would store values of this
currency not with fractions 0.0, 0.2, 0.4, 0.6 or 0.8.

Many calculations with amounts also use more decimal places than
the currency defines.  So there is a need to store a fraction of the smallest unit.
One daily live example would be petrol prices in Germany that have 3 decimal 
places instead of the 2 that the Euro defines.  
Some applications even require non-decimal fractions like 1/3.

This is of course representable with just one number.

Just the final presentation step would convert from a number to a pair of 
ouguiya and khoum.  But according to Wikipedia even this currency is printed 
in decimal:

> The Malagasy ariary and the Mauritanian ouguiya are technically divided 
> into five subunits (the iraimbilanja and khoum respectively) the coins 
> display "1/5" on their face and are referred to as a "fifth" (Khoum/cinquième); 
> These are not used in practice, but when written out, a single significant digit 
> is used. E.g. 1.2 UM.

- Jörg