(*  Title:      nominal_dt_alpha.ML
    Author:     Christian Urban
    Author:     Cezary Kaliszyk

  Performing quotient constructions and lifting theorems
*)

signature NOMINAL_DT_QUOT =
sig
  val define_qtypes: (string list * binding * mixfix) list -> typ list -> term list -> 
    thm list -> local_theory -> Quotient_Info.quotdata_info list * local_theory

  val define_qconsts: typ list -> (string  * term * mixfix) list -> local_theory -> 
    Quotient_Info.qconsts_info list * local_theory

  val define_qperms: typ list -> string list -> (string * sort) list -> 
    (string * term * mixfix) list -> thm list -> local_theory -> local_theory

  val define_qsizes: typ list -> string list -> (string * sort) list -> 
    (string * term * mixfix) list -> local_theory -> local_theory

  val lift_thms: typ list -> thm list -> thm list -> Proof.context -> thm list * Proof.context
end

structure Nominal_Dt_Quot: NOMINAL_DT_QUOT =
struct

(* defines the quotient types *)
fun define_qtypes qtys_descr alpha_tys alpha_trms alpha_equivp_thms lthy =
let
  val qty_args1 = map2 (fn ty => fn trm => (ty, trm, false)) alpha_tys alpha_trms
  val qty_args2 = (qtys_descr ~~ qty_args1) ~~ alpha_equivp_thms
in
  fold_map Quotient_Type.add_quotient_type qty_args2 lthy
end 


(* defines quotient constants *)
fun define_qconsts qtys consts_specs lthy =
let
  val (qconst_infos, lthy') = 
    fold_map (Quotient_Def.lift_raw_const qtys) consts_specs lthy
  val phi = ProofContext.export_morphism lthy' lthy
in
  (map (Quotient_Info.transform_qconsts phi) qconst_infos, lthy')
end


(* defines the quotient permutations and proves pt-class *)
fun define_qperms qtys qfull_ty_names tvs perm_specs raw_perm_laws lthy =
let
  val lthy1 = 
    lthy
    |> Local_Theory.exit_global
    |> Class.instantiation (qfull_ty_names, tvs, @{sort pt}) 
  
  val (qs, lthy2) = define_qconsts qtys perm_specs lthy1

  val ((_, raw_perm_laws'), lthy3) = Variable.importT raw_perm_laws lthy2

  val lifted_perm_laws = 
    map (Quotient_Tacs.lifted lthy3 qtys []) raw_perm_laws'
    |> Variable.exportT lthy3 lthy2

  fun tac _ =
    Class.intro_classes_tac [] THEN
      (ALLGOALS (resolve_tac lifted_perm_laws))
in
  lthy2
  |> Class.prove_instantiation_exit tac 
  |> Named_Target.theory_init
end


(* defines the size functions and proves size-class *)
fun define_qsizes qtys qfull_ty_names tvs size_specs lthy =
let
  fun tac _ = Class.intro_classes_tac []
in
  lthy
  |> Local_Theory.exit_global
  |> Class.instantiation (qfull_ty_names, tvs, @{sort size})
  |> snd o (define_qconsts qtys size_specs)
  |> Class.prove_instantiation_exit tac
  |> Named_Target.theory_init
end


(* lifts a theorem and cleans all "_raw" instances 
   from variable names *)

local
  val any = Scan.one (Symbol.not_eof)
  val raw = Scan.this_string "_raw"
  val exclude =
    Scan.repeat (Scan.unless raw any) --| raw >> implode
  val parser = Scan.repeat (exclude || any)
in
  fun unraw_str s =
   s |> explode
     |> Scan.finite Symbol.stopper parser >> implode 
     |> fst
end

fun unraw_vars_thm thm =
let
  fun unraw_var_str ((s, i), T) = ((unraw_str s, i), T)

  val vars = Term.add_vars (prop_of thm) []
  val vars' = map (Var o unraw_var_str) vars
in
  Thm.certify_instantiate ([], (vars ~~ vars')) thm
end

fun unraw_bounds_thm th =
let
  val trm = Thm.prop_of th
  val trm' = Term.map_abs_vars unraw_str trm
in
  Thm.rename_boundvars trm trm' th
end

fun lift_thms qtys simps thms ctxt =
  (map (Quotient_Tacs.lifted ctxt qtys simps
        #> unraw_bounds_thm
        #> unraw_vars_thm
        #> Drule.zero_var_indexes) thms, ctxt)


end (* structure *)

