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+(* SPDX-License-Identifier: AGPL-3.0-or-later *)
+
+(** Bible books: one canonical id per book, and the tradition that decides
+    which book an id denotes.
+
+    Ids follow the VULGATE structure ([kings_3], [esdras_2],
+    [ecclesiasticus]), because the Vulgate is the default tradition and the
+    shipped 1962 data is Vulgate throughout. An id is internal -- it is never
+    shown to a reader, exactly as a slug is never shown. *)
+
+type id
+
+val to_string : id -> string
+
+(** Resolve one spelling as it appears in the data. Returns [None] for
+    anything not in {!tokens}.
+
+    SEVEN books arrive in two spellings ([Isa]/[Isa.], [3 Kgs.]/[3 Kings],
+    and five more). That inconsistency is INHERITED from lectio's own ini,
+    which is itself generated from missalemeum/Divinum Officium -- it is not
+    a colitur transcription error, and the data is deliberately left
+    untouched. Both spellings resolve here instead. *)
+val of_token : string -> id option
+
+(** Every id this build knows, for coverage checks. *)
+val all : id list
+
+(** Every accepted spelling paired with its id. *)
+val tokens : (string * id) list
+
+(** A numbering tradition: which book an id denotes. Separate from NAMING
+    (what a book is called), which lives in a language file's [\[bible\]]
+    section, because naming varies by language and this does not -- "modern
+    numbering" is the same decision in Latin, Polish and English. *)
+type tradition
+
+(** The identity tradition: the Vulgate, as the 1962 Missal prints it. The
+    default; colitur never silently renumbers. *)
+val vulgate : tradition
+
+(** Build a tradition from an ini section's fields. An entry naming an
+    unknown id on either side is IGNORED, not fatal: a traditions file
+    written for a newer colitur must still work on an older one. Use
+    {!unknown_fields} to report them. *)
+val tradition_of_fields : (string * string) list -> tradition
+
+val unknown_fields : (string * string) list -> string list
+
+val map : tradition -> id -> id