(*  Title:      Pure/Isar/constdefs.ML

    Author:     Makarius, Hagia Maria Sion Abbey (Jerusalem)

Old-style constant definitions, with type-inference and optional

structure context; specifications need to observe strictly sequential

dependencies; no support for overloading.

*)

signature CONSTDEFS =

sig

  val add_constdefs: (Binding.T * string option) list *

    ((Binding.T * string option * mixfix) option *

      (Attrib.binding * string)) list -> theory -> theory

  val add_constdefs_i: (Binding.T * typ option) list *

    ((Binding.T * typ option * mixfix) option *

      ((Binding.T * attribute list) * term)) list -> theory -> theory

end;

structure Constdefs: CONSTDEFS =

struct

(** add_constdefs(_i) **)

fun gen_constdef prep_vars prep_prop prep_att

    structs (raw_decl, ((raw_name, raw_atts), raw_prop)) thy =

  let

    fun err msg ts = error (cat_lines (msg :: map (Syntax.string_of_term_global thy) ts));

    val thy_ctxt = ProofContext.init thy;

    val struct_ctxt = #2 (ProofContext.add_fixes_i structs thy_ctxt);

    val ((d, mx), var_ctxt) =

      (case raw_decl of

        NONE => ((NONE, NoSyn), struct_ctxt)

      | SOME raw_var =>

          struct_ctxt |> prep_vars [raw_var] |-> (fn [(x, T, mx)] =>

            ProofContext.add_fixes_i [(x, T, mx)] #> snd #> pair (SOME x, mx)));

    val prop = prep_prop var_ctxt raw_prop;

    val (c, T) = #1 (LocalDefs.cert_def thy_ctxt (Logic.strip_imp_concl prop));

    val _ =

      (case Option.map Name.name_of d of

        NONE => ()

      | SOME c' =>

          if c <> c' then

            err ("Head of definition " ^ quote c ^ " differs from declaration " ^ quote c') []

          else ());

    val def = Term.subst_atomic [(Free (c, T), Const (Sign.full_bname thy c, T))] prop;

    val name = Thm.def_name_optional c (Name.name_of raw_name);

    val atts = map (prep_att thy) raw_atts;

    val thy' =

      thy

      |> Sign.add_consts_i [(c, T, mx)]

      |> PureThy.add_defs false [((name, def), atts)]

      |-> (fn [thm] => Code.add_default_eqn thm);

  in ((c, T), thy') end;

fun gen_constdefs prep_vars prep_prop prep_att (raw_structs, specs) thy =

  let

    val ctxt = ProofContext.init thy;

    val (structs, _) = prep_vars (map (fn (x, T) => (x, T, Structure)) raw_structs) ctxt;

    val (decls, thy') = fold_map (gen_constdef prep_vars prep_prop prep_att structs) specs thy;

  in Pretty.writeln (ProofDisplay.pretty_consts ctxt (K true) decls); thy' end;

val add_constdefs = gen_constdefs ProofContext.read_vars Syntax.read_prop Attrib.attribute;

val add_constdefs_i = gen_constdefs ProofContext.cert_vars ProofContext.cert_prop (K I);

end;