1 files changed, 33 insertions, 0 deletions
diff --git a/lib/kernel/citation.ml b/lib/kernel/citation.ml
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+(* Scripture references only -- never scripture text (spec §1: that is lectio's
+   job). *)
+type part = First | Psalm | Second | Gospel | Tract | Alleluia | Sequence
+[@@deriving sexp]
+
+let all_parts = [ First; Psalm; Second; Gospel; Tract; Alleluia; Sequence ]
+
+let part_to_string = function
+  | First -> "first" | Psalm -> "psalm" | Second -> "second" | Gospel -> "gospel"
+  | Tract -> "tract" | Alleluia -> "alleluia" | Sequence -> "sequence"
+
+let part_of_string = function
+  | "first" -> Some First | "psalm" -> Some Psalm | "second" -> Some Second
+  | "gospel" -> Some Gospel | "tract" -> Some Tract | "alleluia" -> Some Alleluia
+  | "sequence" -> Some Sequence | _ -> None
+
+type t = { part : part; reference : string }
+
+let sexp_of_t { part; reference } =
+  Sexplib0.Sexp.List [
+    Sexplib0.Sexp_conv.sexp_of_string "part";
+    sexp_of_part part;
+    Sexplib0.Sexp_conv.sexp_of_string "reference";
+    Sexplib0.Sexp_conv.sexp_of_string reference
+  ]
+
+let t_of_sexp sexp =
+  match sexp with
+  | Sexplib0.Sexp.List [ _; part_sexp; _; ref_sexp ] ->
+      let part = part_of_sexp part_sexp in
+      let reference = Sexplib0.Sexp_conv.string_of_sexp ref_sexp in
+      { part; reference }
+  | _ -> Sexplib0.Sexp_conv.of_sexp_error "Citation.t_of_sexp: expected record format" sexp