%-

tydecl case = Nominative | Accusative | Dative | Genitive | Instrumental

tydecl gender = Masculine | Feminine | Neuter

tydecl number = Singular | Plural

; demonstrative pronouns
; "this" or "these"
(:def decline
  (:lambda x (case, gender, number)
    (:match x
      [(Nominative, Masculine, Singular) "þes"]
      [(Accusative, Masculine, Singular) "þisne"]
      [(Genitive, (Masculine|Neuter), Singular) "þisses"]
      [(Dative, (Masculine|Neuter), Singular) "þissum"]
      [(Instrumental, (Masculine|Neuter), Singular) "þys"]
      [((Nominative|Accusative), Neuter, Singular) "þis"]
      [(Nominative, Feminine, Singular) "þeos"]
      [(Accusative, Feminine, Singular) "þas"]
      [((Genitive|Dative|Instrumental), Feminine, Singular) "þisse"]
      [(Nominative, _, Plural) "þas"]
      [(Genitive, _, Plural) "þissa"]
      [(Dative, _, Plural) "þissum"]
      )))