[Development] Alternative plural forms for English (and similar)

[Nicolas Fella]

Hi,

it should be pretty well-known that plurals are a complex topic when it 
comes to translating. While languages like English and German generally 
only distinguish between Singular and Plural, other languages can have 
more complex rules. Qt supports all of that, so far so good.

However, even with English or German there are more subtleties involved. 
When having zero items of something the plural form is used: "0 unread 
messages" is a perfectly grammatical sentence. It often reads nicer to 
instead have "No unread messages" instead though. It's possible to 
achieve that with Qt by an additional if check and using a different 
string, but this doesn't scale with the number of strings to be 
translated and might clash with languages with more complex rules.

Instead it would be nice if Qt's translation system supported this 
natively. From the translator's point of view this effectively becomes 
an additional plural form (n==0). I've had a look at how hard it would 
be to extend Qt to support that. It appears that the QtCore side is 
flexible enough to handle this and reads the rules from the qm file, so 
it's "just" a matter of teaching lupdate/lrelease about the alternative 
plural rules. I've successfully hacked those to change the rules for 
English-ish languages to achieve this, but it would probably need to be 
opt-in in order to not break existing users that don't want this.

Before I spend more time on this, is this something that Qt would be 
willing to support/accept? Are there any other considerations that I 
should be aware of?

Cheers

Nico