[SwiftGen-L10n] Manage positional placeholders (like %2$@)

[AliSoftware]

As in some languages the various texts are not always in the same order, it's not that rare to have positional placeholders like %2$@ in the Localizable.strings strings representing formats.

We need to be able to handle them properly, by storing the associated type at the right position in the [PlaceholderType] array.

Also check the official rules used by printf for that (like what about %3$@ %2$f %@, does the last %@ use the parameter at index 3 because it's incrementing the position from the last positional character encountered (2+1)? or do it use the first parameter? What are the official rules already?)

[NachoSoto]

If I understand this correctly, it should be possible to have the same parameter multiple times, right?
For example:

Text: %1%@; %1%@.

Right now that generates a function with two parameters, but I would expect only one. Can you confirm that's a bug? If so I'll file a separate issue :)

[AliSoftware]

I'd also expect the resulting enum to have only one parameter in such a situation indeed! Good catch

[AliSoftware]

Wait the printf-std syntax is actually %1$@ not %1%@. I thought that was an error when copying your example into the issue but in fact maybe that's why you get that result?

[NachoSoto]

Yup, I got the syntax wrong! My bad.

[AliSoftware]

Well to be fair this syntax is a little RegEx-like and confusing ^^ what an ugly standard/convention in the first place, thank you C legacy ^^