let expand_tag_default (tag : Doc_types.ts_tag) : (string * string) option =
match tag with
| Cs_tag "ABBR" -> Some ("ABBREVIATION", "Abbreviation")
| Cs_tag "ASM" -> Some ("ASSUMPTION", "Assumption")
| Cs_tag "CONJ" -> Some ("CONJECTURE", "Conjecture")
| Cs_tag "CONV" -> Some ("CONVENTION", "Convention")
| Cs_tag "COR" -> Some ("COROLLARY", "Corollary")
| Cs_tag "DEF" -> Some ("DEFINITION", "Definition")
| Cs_tag "EX" -> Some ("EXAMPLE", "Example")
| Cs_tag "FCT" -> Some ("FACT", "Fact")
| Cs_tag "LMA" -> Some ("LEMMA", "Lemma")
| Cs_tag "NTN" -> Some ("NOTATION", "Notation")
| Cs_tag "PRF" -> Some ("PROOF", "Proof")
| Cs_tag "PRP" -> Some ("PROPOSITION", "Proposition")
| Cs_tag "QTN" -> Some ("QUOTATION", "Quotation")
| Cs_tag "RMK" -> Some ("REMARK", "Remark")
| Cs_tag "SLN" -> Some ("SOLUTION", "Solution")
| Cs_tag "THM" -> Some ("THEOREM", "Theorem")
| Cs_tag "TMY" -> Some ("TERMINOLOGY", "Terminology")
| Cs_tag "ABBRS" -> Some ("ABBBREVIATIONS", "Abbbreviations")
| Cs_tag "ASMS" -> Some ("ASSUMPTIONS", "Assumptions")
| Cs_tag "CONJS" -> Some ("CONJECTURES", "Conjectures")
| Cs_tag "CONVS" -> Some ("CONVENTIONS", "Conventions")
| Cs_tag "CORS" -> Some ("COROLLARIES", "Corollaries")
| Cs_tag "DEFS" -> Some ("DEFINITIONS", "Definitions")
| Cs_tag "EXS" -> Some ("EXAMPLES", "Examples")
| Cs_tag "FCTS" -> Some ("FACTS", "Facts")
| Cs_tag "LMAS" -> Some ("LEMMAS", "Lemmas")
| Cs_tag "NTNS" -> Some ("NOTATIONS", "Notations")
| Cs_tag "PRFS" -> Some ("PROOFS", "Proofs")
| Cs_tag "PRPS" -> Some ("PROPOSITIONS", "Propositions")
| Cs_tag "QTNS" -> Some ("QUOTATIONS", "Quotations")
| Cs_tag "RMKS" -> Some ("REMARKS", "Remarks")
| Cs_tag "SLNS" -> Some ("SOLUTIONS", "Solutions")
| Cs_tag "THMS" -> Some ("THEOREMS", "Theorems")
| Cs_tag "PAR"
| Cs_tag "ITM"
| Cs_tag "DSP"
| Cs_tag "BIB" -> None
| Cs_tag tag_string -> let _ : unit = IO.print_warning ("WARNING: undefined tag: " ^ tag_string) in None