Returning currency without price

Does it makes sense to return a Price instance with currency set and without a price value?

Actually if we have a substring inside a string that matches with an existing currency, it will be returned even if we are not mentioning the currency:

In [1]: Price.fromstring("STRING WITH NO PRICE BUT HAS A WORD THAT CONTAINS PART OF A CURRENCY NAME: EUROPE")
Out[1]: Price(amount=None, currency='EUR')

This happens because we use regexes to match the currencies inside a string. But this approach would create a problem when single-letter currencies is handled better (#3) .

I can see two options to handle this scenario:

1. Consider as currency only if the substring is surrounded by whitespaces:

In [2]: Price.fromstring("SOMETHING EUROPE SOMETHING")
Out[2]: Price(amount=None, currency=None)

In [3]: Price.fromstring("SOMETHING EUR SOMETHING")
Out[3]: Price(amount=None, currency='EUR')

1. Consider as currency only if the entire string matches exactly with the currency name:

In [4]: Price.fromstring("EUR")
Out[4]: Price(amount=None, currency='EUR')

In [5]: Price.fromstring("SOMETHING EUR SOMETHING")
Out[5]: Price(amount=None, currency=None)

[Gallaecio]

I think so.

When a real-life scenario comes up where this is troublesome, we can look into improvements to solve or mitigate such issues. For example, ignore specific currency expressions on specific locales (I assume we are getting locale support à la dateparser eventually), such as ignoring “R” on languages where “R” is a common word and they always use a different text when referring to the “R” currency.

[Gallaecio]

I think option 1 is the way to go. We just need to improve the regular expressions that we use to match currencies so that “Europa” does not count as “EUR”.