Order of modifiers and flags in parameter expansion

[Hannu Koivisto <azure@xxxxxx>]

Greetings,

I have a script foo-files that prints filenames separated by
newlines.  I want directory parts of those filenames and then I
want to get rid of duplicates.  So I write
${(u)${(f)"$(foo-files)"}:h} which works and the fact that it works
means that the h modifier is applied before the u flag.
Unfortunately I can't find where in the manual this order is
specified.  I have read 13.3.2 but it didn't seem to consider the u
flag even indirectly.  Any clues?

-- 
Hannu