For this ICU ticket:
http://bugs.icu-project.org/trac/ticket/10637 For Chinese calendar, need way to format/parse using current Gregorian year
We may need a way in date patterns to specify year (and possibly month, day) for "related" calendars associated with some non-Gregorian calendars. In particular, for East Asian lunar calendars, a year or date in some Gregorian-like calendar is often specified along with the lunar date in order to disambiguate era.
One possibility is that we could designate, say, 'r' to indicate the year in the related calendar (Gregorian by default). This needs more design. In any case, the only CLDR work for this would be a spec change to designate pattern characters.
Nte, available pattern characters are currently "bBCfiInNopPrRtT"