Usage

Exclude attributes when compare

require "pubid-core"

pubid_first = Identifier.parse("ISO 1:1999")
pubid_second = Identifier.parse("ISO 1")

pubid_first == pubid_second
=> false

pubid_first.exclude(:year) == pubid_second
=> true

Using #to_h to convert identifier to hash

require "pubid-core"

pubid = Identifier.parse("ISO 1:1999")
pubid.to_h
=> { publisher: "ISO", number: 1, year: 1999 }