Certification union for Vendor.certified: a boolean flag, a bounded decimal rating, a letter-grade string,
or a gYear.
Spans the xsd:boolean, numeric and xsd:string tiers of the §5.7.5 sort order: a gYear is not a processing
type, so it ranks as an opaque xsd:string (§3). The grade pattern keeps the string variant lexically disjoint
from the gYear variant, so every value singles out exactly one branch (§3.3).
Certification union for
Vendor.certified: a boolean flag, a bounded decimal rating, a letter-grade string, or a gYear.Spans the
xsd:boolean,numericandxsd:stringtiers of the §5.7.5 sort order: a gYear is not a processing type, so it ranks as an opaquexsd:string(§3). The grade pattern keeps the string variant lexically disjoint from the gYear variant, so every value singles out exactly one branch (§3.3).