-- current exchange rate. Needs to be updated frequently to be useful.
-- though a collection of historical data would sometimes be useful too.
|context> => |context: currency exchange rates>

full-name |currency: USD> => |currency: US Dollar>
full-name |currency: GBP> => |currency: British Pound Sterling>

to-USD | currency: USD: _x> => |currency: USD: _x>
to USD | currency: GBP: _x > => |currency: USD: _x*1.62>

to-GBP | currency: USD: _x> => | currency: GBP: _x*0.62>
to-GBP | currency: GBP: _x> => | currency: GBP: _x >


-- where to get more information:
more-info |context: currency exchange rates> => |url: http://www.xe.com/currencyconverter/>