NewNamePolicyEngine creates a new NamePolicyEngine with NamePolicyOptions.

CannotMatch is the type of error returned when an error happens when matching SAN types.

CannotParseDomain is returned when an error occurs when parsing the domain part of SAN or subject.

CannotParseRFC822Name is returned when an error occurs when parsing an email address.

NotAllowed results when an instance of NamePolicyEngine determines that there's a constraint which doesn't permit a DNS or another type of SAN to be signed (or otherwise used).