(************************************************************************)
(*  v      *   The Coq Proof Assistant  /  The Coq Development Team     *)
(* <O___,, * CNRS-Ecole Polytechnique-INRIA Futurs-Universite Paris Sud *)
(*   \VV/  **************************************************************)
(*    //   *      This file is distributed under the terms of the       *)
(*         *       GNU Lesser General Public License Version 2.1        *)
(************************************************************************)

(*i $Id: extract_env.ml 6328 2004-11-18 17:31:41Z sacerdot $ i*)

open Term
open Declarations
open Names
open Libnames
open Pp
open Util
open Miniml
open Table
open Extraction
open Modutil
open Common
open Mod_subst

(*s Obtaining Coq environment. *)

let toplevel_env () = 
  let seg = Lib.contents_after None in 
  let get_reference = function 
    | (_,kn), Lib.Leaf o ->
	let mp,_,l = repr_kn kn in 
	let seb = match Libobject.object_tag o with
	  | "CONSTANT" -> SEBconst (Global.lookup_constant (constant_of_kn kn))
	  | "INDUCTIVE" -> SEBmind (Global.lookup_mind kn) 
	  | "MODULE" -> SEBmodule (Global.lookup_module (MPdot (mp,l)))
	  | "MODULE TYPE" -> SEBmodtype (Global.lookup_modtype kn)
	  | _ -> failwith "caught"
	in l,seb
    | _ -> failwith "caught"
  in 
  match current_toplevel () with 
    | MPself msid -> MEBstruct (msid, List.rev (map_succeed get_reference seg))
    | _ -> assert false

let environment_until dir_opt = 
  let rec parse = function 
    | [] when dir_opt = None -> [current_toplevel (), toplevel_env ()]
    | [] -> [] 
    | d :: l -> 
	match (Global.lookup_module (MPfile d)).mod_expr with 
	  | Some meb -> 
	      if dir_opt = Some d then [MPfile d, meb]
	      else (MPfile d, meb) :: (parse l)
	  | _ -> assert false
  in parse (Library.loaded_libraries ())

type visit =
 { mutable kn : KNset.t; mutable ref : Refset.t; mutable mp : MPset.t }

let in_kn v kn = KNset.mem kn v.kn
let in_ref v ref = Refset.mem ref v.ref
let in_mp v mp = MPset.mem mp v.mp

let visit_mp v mp = v.mp <- MPset.union (prefixes_mp mp) v.mp
let visit_kn v kn = v.kn <- KNset.add kn v.kn; visit_mp v (modpath kn)
let visit_ref v r =
 let r =
  (* if we meet a constructor we must export the inductive definition *)
  match r with
     ConstructRef (r,_) -> IndRef r
   | _ -> r
 in
  v.ref <- Refset.add r v.ref; visit_mp v (modpath_of_r r) 

exception Impossible

let check_arity env cb = 
  if Reduction.is_arity env cb.const_type then raise Impossible

let check_fix env cb i = 
  match cb.const_body with 
    | None -> raise Impossible
    | Some lbody -> 
	match kind_of_term (Declarations.force lbody) with 
	  | Fix ((_,j),recd) when i=j -> check_arity env cb; (true,recd)
	  | CoFix (j,recd) when i=j -> check_arity env cb; (false,recd)
	  | _ -> raise Impossible

let factor_fix env l cb msb = 
  let _,recd as check = check_fix env cb 0 in 
  let n = Array.length (let fi,_,_ = recd in fi) in
  if n = 1 then [|l|], recd, msb
  else begin 
    if List.length msb < n-1 then raise Impossible; 
    let msb', msb'' = list_chop (n-1) msb in 
    let labels = Array.make n l in 
    list_iter_i 
      (fun j -> 
	 function 
	   | (l,SEBconst cb') -> 
	       if check <> check_fix env cb' (j+1) then raise Impossible; 
	       labels.(j+1) <- l; 
	   | _ -> raise Impossible) msb'; 
    labels, recd, msb''
  end

let get_decl_references v d = 
  let f = visit_ref v in decl_iter_references f f f d

let get_spec_references v s = 
  let f = visit_ref v in spec_iter_references f f f s

let rec extract_msig env v mp = function 
  | [] -> [] 
  | (l,SPBconst cb) :: msig -> 
      let kn = make_con mp empty_dirpath l in 
      let s = extract_constant_spec env kn cb in 
      if logical_spec s then extract_msig env v mp msig
      else begin
	get_spec_references v s; 
	(l,Spec s) :: (extract_msig env v mp msig)
      end
  | (l,SPBmind cb) :: msig -> 
      let kn = make_kn mp empty_dirpath l in 
      let s = Sind (kn, extract_inductive env kn) in 
      if logical_spec s then extract_msig env v mp msig
      else begin 
	get_spec_references v s; 
	(l,Spec s) :: (extract_msig env v mp msig)
      end
  | (l,SPBmodule {msb_modtype=mtb}) :: msig -> 
(*i      let mpo = Some (MPdot (mp,l)) in  i*)
      (l,Smodule (extract_mtb env v None (*i mpo i*) mtb)) :: (extract_msig env v mp msig)
  | (l,SPBmodtype mtb) :: msig -> 
      (l,Smodtype (extract_mtb env v None mtb)) :: (extract_msig env v mp msig)

and extract_mtb env v mpo = function 
  | MTBident kn -> visit_kn v kn; MTident kn 
  | MTBfunsig (mbid, mtb, mtb') -> 
      let mp = MPbound mbid in 
      let env' = Modops.add_module mp (Modops.module_body_of_type mtb) env in 
      MTfunsig (mbid, extract_mtb env v None mtb, 
		extract_mtb env' v None mtb') 
  | MTBsig (msid, msig) -> 
      let mp, msig = match mpo with 
	| None -> MPself msid, msig
	| Some mp -> mp, Modops.subst_signature_msid msid mp msig
      in
      let env' = Modops.add_signature mp msig env in 
      MTsig (msid, extract_msig env' v mp msig) 

let rec extract_msb env v mp all = function 
  | [] -> [] 
  | (l,SEBconst cb) :: msb -> 
      (try 
	 let vl,recd,msb = factor_fix env l cb msb in 
	 let vkn = Array.map (fun id -> make_con mp empty_dirpath id) vl in
	 let ms = extract_msb env v mp all msb in 
	 let b = array_exists (fun con -> in_ref v (ConstRef con)) vkn in 
	 if all || b then 
	   let d = extract_fixpoint env vkn recd in 
	   if (not b) && (logical_decl d) then ms 
	   else begin get_decl_references v d; (l,SEdecl d) :: ms end
	 else ms
       with Impossible ->
	 let ms = extract_msb env v mp all msb in 
	 let kn = make_con mp empty_dirpath l in 
	 let b = in_ref v (ConstRef kn) in 
	 if all || b then 
	   let d = extract_constant env kn cb in
	   if (not b) && (logical_decl d) then ms 
	   else begin get_decl_references v d; (l,SEdecl d) :: ms end
	 else ms)
  | (l,SEBmind mib) :: msb ->
      let ms = extract_msb env v mp all msb in
      let kn = make_kn mp empty_dirpath l in 
      let b = in_ref v (IndRef (kn,0)) in  (* 0 is dummy *)
      if all || b then 
	let d = Dind (kn, extract_inductive env kn) in 
	if (not b) && (logical_decl d) then ms 
	else begin get_decl_references v d; (l,SEdecl d) :: ms end
      else ms
  | (l,SEBmodule mb) :: msb -> 
      let ms = extract_msb env v mp all msb in
      let mp = MPdot (mp,l) in 
      if all || in_mp v mp then 
	(l,SEmodule (extract_module env v mp true mb)) :: ms
      else ms
  | (l,SEBmodtype mtb) :: msb ->
      let ms = extract_msb env v mp all msb in
      let kn = make_kn mp empty_dirpath l in
      if all || in_kn v kn then 
	(l,SEmodtype (extract_mtb env v None mtb)) :: ms
      else ms

and extract_meb env v mpo all = function 
  | MEBident (MPfile d) -> error_MPfile_as_mod d (* temporary (I hope) *)
  | MEBident mp -> visit_mp v mp; MEident mp 
  | MEBapply (meb, meb',_) -> 
      MEapply (extract_meb env v None true meb, 
	       extract_meb env v None true meb')
  | MEBfunctor (mbid, mtb, meb) -> 
      let mp = MPbound mbid in 
      let env' = Modops.add_module mp (Modops.module_body_of_type mtb) env in 
      MEfunctor (mbid, extract_mtb env v None mtb, 
		 extract_meb env' v None true meb)
  | MEBstruct (msid, msb) -> 
      let mp,msb = match mpo with 
	| None -> MPself msid, msb 
	| Some mp -> mp, subst_msb (map_msid msid mp) msb
      in 
      let env' = add_structure mp msb env in 
      MEstruct (msid, extract_msb env' v mp all msb) 

and extract_module env v mp all mb = 
  (* [mb.mod_expr <> None ], since we look at modules from outside. *)
  (* Example of module with empty [mod_expr] is X inside a Module F [X:SIG]. *)
  let meb = out_some mb.mod_expr in
  let mtb = match mb.mod_user_type with None -> mb.mod_type | Some mt -> mt in
  (* Because of the "with" construct, the module type can be [MTBsig] with *)
  (* a msid different from the one of the module. Here is the patch. *)
  let mtb = replicate_msid meb mtb in
  { ml_mod_expr = extract_meb env v (Some mp) all meb;
    ml_mod_type = extract_mtb env v None mtb }

let unpack = function MEstruct (_,sel) -> sel | _ -> assert false 

let mono_environment refs mpl = 
  let l = environment_until None in 
  let v = 
    let add_ref r = Refset.add r in 
    let refs = List.fold_right add_ref refs Refset.empty in 
    let add_mp mp = MPset.union (prefixes_mp mp) in
    let mps = List.fold_right add_mp mpl MPset.empty in 
    let mps = Refset.fold (fun k -> add_mp (modpath_of_r k)) refs mps in 
    { kn = KNset.empty; ref = refs; mp = mps }
  in 
  let env = Global.env () in 
  List.rev_map (fun (mp,m) -> mp, unpack (extract_meb env v (Some mp) false m)) 
    (List.rev l)

(*s Recursive extraction in the Coq toplevel. The vernacular command is
    \verb!Recursive Extraction! [qualid1] ... [qualidn]. We use [extract_env]
    to get the saturated environment to extract. *)

let mono_extraction (f,m) qualids = 
  check_inside_section (); 
  check_inside_module ();
  let rec find = function 
    | [] -> [],[]
    | q::l -> 
	let refs,mps = find l in 
	try 
	  let mp = Nametab.locate_module (snd (qualid_of_reference q))
	  in refs,(mp::mps)
	with Not_found -> (Nametab.global q)::refs, mps 
  in 	    
  let refs,mps = find qualids in
  let prm = {modular=false; mod_name = m; to_appear= refs} in
  let struc = optimize_struct prm None (mono_environment refs mps) in 
  print_structure_to_file f prm struc; 
  reset_tables ()

let extraction_rec = mono_extraction (None,id_of_string "Main")

(*s Extraction in the Coq toplevel. We display the extracted term in
    Ocaml syntax and we use the Coq printers for globals. The
    vernacular command is \verb!Extraction! [qualid]. *)

let extraction qid = 
  check_inside_section (); 
  check_inside_module ();
  try 
    let _ = Nametab.locate_module (snd (qualid_of_reference qid)) in 
    extraction_rec [qid]
  with Not_found -> 
    let r = Nametab.global qid in 
    if is_custom r then
      msgnl (str "User defined extraction:" ++ spc () ++ 
	     str (find_custom r) ++ fnl ()) 
    else begin 
      let prm = 
	{ modular = false; mod_name = id_of_string "Main"; to_appear = [r]} in 
      let struc = optimize_struct prm None (mono_environment [r] []) in 
      let d = get_decl_in_structure r struc in 
      print_one_decl struc (modpath_of_r r) d;
      reset_tables ()
    end

(*s Extraction to a file (necessarily recursive). 
    The vernacular command is 
    \verb!Extraction "file"! [qualid1] ... [qualidn].*)

let lang_suffix () = match lang () with 
  | Ocaml -> ".ml",".mli"
  | Haskell -> ".hs",".hi"
  | Scheme -> ".scm",".scm"
  | Toplevel -> assert false

let filename f = 
  let s,s' = lang_suffix () in
  if Filename.check_suffix f s then 
    let f' = Filename.chop_suffix f s in 
    Some (f,f'^s'),id_of_string f' 
  else Some (f^s,f^s'),id_of_string f

let extraction_file f vl =
  if lang () = Toplevel then error_toplevel () 
  else mono_extraction (filename f) vl

(*s Extraction of a module at the toplevel. *)

let extraction_module m = 
  check_inside_section (); 
  check_inside_module ();
  match lang () with 
    | Toplevel -> error_toplevel ()
    | Scheme -> error_scheme ()
    | _ -> 
	let q = snd (qualid_of_reference m) in 
	let mp = 
	  try Nametab.locate_module q
	  with Not_found -> error_unknown_module q
	in 
	let b = is_modfile mp in 
	let prm = {modular=b; mod_name = id_of_string ""; to_appear= []} in
	let l = environment_until None in 
	let v={ kn = KNset.empty ; ref = Refset.empty; mp = prefixes_mp mp } in
	let env = Global.env () in 
	let struc = 
	  List.rev_map
	    (fun (mp,m) -> mp, unpack (extract_meb env v (Some mp) b m)) 
	    (List.rev l)
	in 
	let struc = optimize_struct prm None struc in 
	let struc = 
	  let bmp = base_mp mp in 
	  try [bmp, List.assoc bmp struc] with Not_found -> assert false
	in
	print_structure_to_file None prm struc; 
	reset_tables ()

(*s (Recursive) Extraction of a library. The vernacular command is 
  \verb!(Recursive) Extraction Library! [M]. *) 

let module_file_name m = match lang () with 
  | Ocaml -> let f = String.uncapitalize (string_of_id m) in  f^".ml", f^".mli"
  | Haskell -> let f = String.capitalize (string_of_id m) in f^".hs", f^".hi"
  | _ -> assert false

let dir_module_of_id m = 
  let q = make_short_qualid m in 
  try Nametab.full_name_module q with Not_found -> error_unknown_module q

let extraction_library is_rec m =
  check_inside_section (); 
  check_inside_module ();  
  match lang () with 
    | Toplevel -> error_toplevel ()
    | Scheme -> error_scheme ()
    | _ -> 
	let dir_m = dir_module_of_id m in 
	let v =
         { kn = KNset.empty; ref = Refset.empty;
           mp = MPset.singleton (MPfile dir_m) } in 
	let l = environment_until (Some dir_m) in 
	let struc = 
	  let env = Global.env () in
	  let select l (mp,meb) = 
	    if in_mp v mp (* [mp] est long -> [in_mp] peut etre sans [long_mp] *)
	    then (mp, unpack (extract_meb env v (Some mp) true meb)) :: l 
	    else l
	  in 
	  List.fold_left select [] (List.rev l)
	in 
	let dummy_prm = {modular=true; mod_name=m; to_appear=[]} in
	let struc = optimize_struct dummy_prm None struc in 
	let rec print = function 
	  | [] -> () 
	  | (MPfile dir, _) :: l when not is_rec && dir <> dir_m -> print l 
	  | (MPfile dir, sel) as e :: l -> 
	      let short_m = snd (split_dirpath dir) in
	      let f = module_file_name short_m in 
	      let prm = {modular=true;mod_name=short_m;to_appear=[]} in
	      print_structure_to_file (Some f) prm [e]; 
	      print l 
	  | _ -> assert false
	in print struc; 
	reset_tables ()