typer.ml 39.5 KB
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(* TODO:
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 - rewrite type-checking of operators to propagate constraint
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 - optimize computation of pattern free variables
 - check whether it is worth using recursive hash-consing internally
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*)

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let warning loc msg =
  Format.fprintf !Location.warning_ppf "Warning %a:@\n%a%s@\n" 
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    Location.print_loc (loc,`Full)
    Location.html_hilight (loc,`Full)
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    msg

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(* I. Transform the abstract syntax of types and patterns into
      the internal form *)
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open Location
open Ast
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open Ident
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module TypeEnv = Map.Make(U)
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exception NonExhaustive of Types.descr
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exception Constraint of Types.descr * Types.descr
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exception ShouldHave of Types.descr * string
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exception ShouldHave2 of Types.descr * string * Types.descr
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exception WrongLabel of Types.descr * label
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exception UnboundId of id
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exception Error of string
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let raise_loc loc exn = raise (Location (loc,`Full,exn))
let raise_loc_str loc ofs exn = raise (Location (loc,`Char ofs,exn))
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let error loc msg = raise_loc loc (Error msg)
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  (* Schema datastructures *)

module StringSet = Set.Make (String)
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  (* just to remember imported schemas *)
let schemas = State.ref "Typer.schemas" StringSet.empty
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let schema_types = State.ref "Typer.schema_types" (Hashtbl.create 51)
let schema_elements = State.ref "Typer.schema_elements" (Hashtbl.create 51)
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let schema_attributes = State.ref "Typer.schema_attributes" (Hashtbl.create 51)
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(* Eliminate Recursion, propagate Sequence Capture Variables *)

let rec seq_vars accu = function
  | Epsilon | Elem _ -> accu
  | Seq (r1,r2) | Alt (r1,r2) -> seq_vars (seq_vars accu r1) r2
  | Star r | WeakStar r -> seq_vars accu r
  | SeqCapture (v,r) -> seq_vars (IdSet.add v accu) r

type derecurs_slot = {
  ploc : Location.loc;
  pid  : int;
  mutable ploop : bool;
  mutable pdescr : derecurs option
} and derecurs =
  | PAlias of derecurs_slot
  | PType of Types.descr
  | POr of derecurs * derecurs
  | PAnd of derecurs * derecurs
  | PDiff of derecurs * derecurs
  | PTimes of derecurs * derecurs
  | PXml of derecurs * derecurs
  | PArrow of derecurs * derecurs
  | POptional of derecurs
  | PRecord of bool * derecurs label_map
  | PCapture of id
  | PConstant of id * Types.const
  | PRegexp of derecurs_regexp * derecurs
and derecurs_regexp =
  | PEpsilon
  | PElem of derecurs
  | PSeq of derecurs_regexp * derecurs_regexp
  | PAlt of derecurs_regexp * derecurs_regexp
  | PStar of derecurs_regexp
  | PWeakStar of derecurs_regexp

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type tenv = {
  tenv_names : derecurs_slot TypeEnv.t;
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  tenv_nspref: Ns.table;
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  tenv_loc   : Location.loc
}
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let get_ns_table tenv = tenv.tenv_nspref
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let rec hash_derecurs = function
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  | PAlias s -> 
      s.pid
  | PType t -> 
      1 + 17 * (Types.hash_descr t)
  | POr (p1,p2) -> 
      2 + 17 * (hash_derecurs p1) + 257 * (hash_derecurs p2)
  | PAnd (p1,p2) -> 
      3 + 17 * (hash_derecurs p1) + 257 * (hash_derecurs p2)
  | PDiff (p1,p2) -> 
      4 + 17 * (hash_derecurs p1) + 257 * (hash_derecurs p2)
  | PTimes (p1,p2) -> 
      5 + 17 * (hash_derecurs p1) + 257 * (hash_derecurs p2)
  | PXml (p1,p2) -> 
      6 + 17 * (hash_derecurs p1) + 257 * (hash_derecurs p2)
  | PArrow (p1,p2) -> 
      7 + 17 * (hash_derecurs p1) + 257 * (hash_derecurs p2)
  | POptional p -> 
      8 + 17 * (hash_derecurs p)
  | PRecord (o,r) -> 
      (if o then 9 else 10) + 17 * (LabelMap.hash hash_derecurs r)
  | PCapture x -> 
      11 + 17 * (Id.hash x)
  | PConstant (x,c) -> 
      12 + 17 * (Id.hash x) + 257 * (Types.hash_const c)
  | PRegexp (p,q) -> 
      13 + 17 * (hash_derecurs_regexp p) + 257 * (hash_derecurs q)
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and hash_derecurs_regexp = function
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  | PEpsilon -> 
      1
  | PElem p -> 
      2 + 17 * (hash_derecurs p)
  | PSeq (p1,p2) -> 
      3 + 17 * (hash_derecurs_regexp p1) + 257 * (hash_derecurs_regexp p2)
  | PAlt (p1,p2) -> 
      4 + 17 * (hash_derecurs_regexp p1) + 257 * (hash_derecurs_regexp p2)
  | PStar p -> 
      5 + 17 * (hash_derecurs_regexp p)
  | PWeakStar p -> 
      6 + 17 * (hash_derecurs_regexp p)
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let rec equal_derecurs p1 p2 = (p1 == p2) || match p1,p2 with
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  | PAlias s1, PAlias s2 -> 
      s1 == s2
  | PType t1, PType t2 -> 
      Types.equal_descr t1 t2
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  | POr (p1,q1), POr (p2,q2)
  | PAnd (p1,q1), PAnd (p2,q2)
  | PDiff (p1,q1), PDiff (p2,q2)
  | PTimes (p1,q1), PTimes (p2,q2)
  | PXml (p1,q1), PXml (p2,q2)
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  | PArrow (p1,q1), PArrow (p2,q2) -> 
      (equal_derecurs p1 p2) && (equal_derecurs q1 q2)
  | POptional p1, POptional p2 -> 
      equal_derecurs p1 p2
  | PRecord (o1,r1), PRecord (o2,r2) -> 
      (o1 == o2) && (LabelMap.equal equal_derecurs r1 r2)
  | PCapture x1, PCapture x2 -> 
      Id.equal x1 x2
  | PConstant (x1,c1), PConstant (x2,c2) -> 
      (Id.equal x1 x2) && (Types.equal_const c1 c2)
  | PRegexp (p1,q1), PRegexp (p2,q2) -> 
      (equal_derecurs_regexp p1 p2) && (equal_derecurs q1 q2)
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  | _ -> false
and equal_derecurs_regexp r1 r2 = match r1,r2 with
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  | PEpsilon, PEpsilon -> 
      true
  | PElem p1, PElem p2 -> 
      equal_derecurs p1 p2
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  | PSeq (p1,q1), PSeq (p2,q2) 
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  | PAlt (p1,q1), PAlt (p2,q2) -> 
      (equal_derecurs_regexp p1 p2) && (equal_derecurs_regexp q1 q2)
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  | PStar p1, PStar p2
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  | PWeakStar p1, PWeakStar p2 -> 
      equal_derecurs_regexp p1 p2
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  | _ -> false
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module DerecursTable = Hashtbl.Make(
  struct 
    type t = derecurs 
    let hash = hash_derecurs
    let equal = equal_derecurs
  end
)

module RE = Hashtbl.Make(
  struct 
    type t = derecurs_regexp * derecurs 
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    let hash (p,q) = 
      (hash_derecurs_regexp p) + 17 * (hash_derecurs q)
    let equal (p1,q1) (p2,q2) = 
      (equal_derecurs_regexp p1 p2) && (equal_derecurs q1 q2)
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  end
)
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let counter = State.ref "Typer.counter - derecurs" 0
let mk_slot loc = 
  incr counter; 
  { ploop = false; ploc = loc; pid = !counter; pdescr = None }
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let protect_error_ns loc f x =
  try f x
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  with Ns.UnknownPrefix ns ->
    raise_loc_generic loc 
    ("Undefined namespace prefix " ^ (U.to_string ns))

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let parse_atom env loc t =
  let (ns,l) = protect_error_ns loc (Ns.map_tag env.tenv_nspref) t in
  Atoms.mk ns l
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let parse_ns env loc ns =
  protect_error_ns loc (Ns.map_prefix env.tenv_nspref) ns
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let const env loc = function
  | Const_internal c -> c
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  | Const_atom t -> Types.Atom (parse_atom env loc t)
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let parse_label env loc t =
  let (ns,l) = protect_error_ns loc (Ns.map_attr env.tenv_nspref) t in
  LabelPool.mk (ns,l)

let parse_record env loc f r =
  let r = List.map (fun (l,x) -> (parse_label env loc l, f x)) r in
  LabelMap.from_list (fun _ _ -> raise_loc_generic loc "Duplicated record field") r

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let rec derecurs env p = match p.descr with
  | PatVar v ->
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      (try PAlias (TypeEnv.find v env.tenv_names)
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       with Not_found -> 
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	 raise_loc_generic p.loc ("Undefined type/pattern " ^ (U.to_string v)))
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  | SchemaVar (kind, schema, item) ->
      let try_elt () = fst (Hashtbl.find !schema_elements (schema, item)) in
      let try_typ () = Hashtbl.find !schema_types (schema, item) in
      let try_att () = Hashtbl.find !schema_attributes (schema, item) in
      (match kind with
      | `Element ->
          (try
            PType (try_elt ())
          with Not_found ->
            failwith (Printf.sprintf
              "No element named '%s' found in schema '%s'" item schema))
      | `Type ->
          (try
            PType (try_typ ())
          with Not_found ->
            failwith (Printf.sprintf
              "No type named '%s' found in schema '%s'" item schema))
      | `Attribute ->
          (try
            PType (try_att ())
          with Not_found ->
            failwith (Printf.sprintf
              "No attribute named '%s' found in schema '%s'" item schema))
      | `Any ->
          PType
            (try try_elt () with Not_found ->
              (try try_typ () with Not_found ->
                (try try_att () with Not_found ->
                  failwith (Printf.sprintf
                    "No item named '%s' found in schema '%s'" item schema)))))
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  | Recurs (p,b) -> derecurs (derecurs_def env b) p
  | Internal t -> PType t
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  | AtomT t -> PType (Types.atom (Atoms.atom (parse_atom env p.loc t)))
  | NsT ns -> PType (Types.atom (Atoms.any_in_ns (parse_ns env p.loc ns)))
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  | Or (p1,p2) -> POr (derecurs env p1, derecurs env p2)
  | And (p1,p2) -> PAnd (derecurs env p1, derecurs env p2)
  | Diff (p1,p2) -> PDiff (derecurs env p1, derecurs env p2)
  | Prod (p1,p2) -> PTimes (derecurs env p1, derecurs env p2)
  | XmlT (p1,p2) -> PXml (derecurs env p1, derecurs env p2)
  | Arrow (p1,p2) -> PArrow (derecurs env p1, derecurs env p2)
  | Optional p -> POptional (derecurs env p)
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  | Record (o,r) -> PRecord (o, parse_record env p.loc (derecurs env) r)
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  | Capture x -> PCapture x
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  | Constant (x,c) -> PConstant (x,const env p.loc c)
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  | Regexp (r,q) -> 
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      let constant_nil t v = 
	PAnd (t, PConstant (v, Types.Atom Sequence.nil_atom)) in
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      let vars = seq_vars IdSet.empty r in
      let q = IdSet.fold constant_nil (derecurs env q) vars in
      let r = derecurs_regexp (fun p -> p) env r in
      PRegexp (r, q)
and derecurs_regexp vars env = function
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  | Epsilon -> 
      PEpsilon
  | Elem p -> 
      PElem (vars (derecurs env p))
  | Seq (p1,p2) -> 
      PSeq (derecurs_regexp vars env p1, derecurs_regexp vars env p2)
  | Alt (p1,p2) -> 
      PAlt (derecurs_regexp vars env p1, derecurs_regexp vars env p2)
  | Star p -> 
      PStar (derecurs_regexp vars env p)
  | WeakStar p -> 
      PWeakStar (derecurs_regexp vars env p)
  | SeqCapture (x,p) -> 
      derecurs_regexp (fun p -> PAnd (vars p, PCapture x)) env p
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and derecurs_def env b =
  let b = List.map (fun (v,p) -> (v,p,mk_slot p.loc)) b in
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  let n = 
    List.fold_left (fun env (v,p,s) -> TypeEnv.add v s env) env.tenv_names b in
  let env = { env with tenv_names = n } in
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  List.iter (fun (v,p,s) -> s.pdescr <- Some (derecurs env p)) b;
  env
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(* Stratification and recursive hash-consing *)
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type descr = 
  | IType of Types.descr
  | IOr of descr * descr
  | IAnd of descr * descr
  | IDiff of descr * descr
  | ITimes of slot * slot
  | IXml of slot * slot
  | IArrow of slot * slot
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  | IOptional of descr
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  | IRecord of bool * slot label_map
  | ICapture of id
  | IConstant of id * Types.const
and slot = {
  mutable fv : fv option;
  mutable hash : int option;
  mutable rank1: int; mutable rank2: int;
  mutable gen1 : int; mutable gen2: int;
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  mutable d    : descr option
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}
    
let descr s = 
  match s.d with
    | Some d -> d
    | None -> assert false
	
let gen = ref 0
let rank = ref 0
	     
let rec hash_descr = function
  | IType x -> Types.hash_descr x
  | IOr (d1,d2) -> 1 + 17 * (hash_descr d1) + 257 * (hash_descr d2)
  | IAnd (d1,d2) -> 2 + 17 * (hash_descr d1) + 257 * (hash_descr d2)
  | IDiff (d1,d2) -> 3 + 17 * (hash_descr d1) + 257 * (hash_descr d2)
  | IOptional d -> 4 + 17 * (hash_descr d)
  | ITimes (s1,s2) -> 5 + 17 * (hash_slot s1) + 257 * (hash_slot s2)
  | IXml (s1,s2) -> 6 + 17 * (hash_slot s1) + 257 * (hash_slot s2)
  | IArrow (s1,s2) -> 7 + 17 * (hash_slot s1) + 257 * (hash_slot s2)
  | IRecord (o,r) -> (if o then 8 else 9) + 17 * (LabelMap.hash hash_slot r)
  | ICapture x -> 10 + 17 * (Id.hash x)
  | IConstant (x,y) -> 11 + 17 * (Id.hash x) + 257 * (Types.hash_const y)
and hash_slot s =
  if s.gen1 = !gen then 13 * s.rank1
  else (
    incr rank;
    s.rank1 <- !rank; s.gen1 <- !gen;
    hash_descr (descr s)
  )
    
let rec equal_descr d1 d2 = 
  match (d1,d2) with
  | IType x1, IType x2 -> Types.equal_descr x1 x2
  | IOr (x1,y1), IOr (x2,y2) 
  | IAnd (x1,y1), IAnd (x2,y2) 
  | IDiff (x1,y1), IDiff (x2,y2) -> (equal_descr x1 x2) && (equal_descr y1 y2)
  | IOptional x1, IOptional x2 -> equal_descr x1 x2
  | ITimes (x1,y1), ITimes (x2,y2) 
  | IXml (x1,y1), IXml (x2,y2) 
  | IArrow (x1,y1), IArrow (x2,y2) -> (equal_slot x1 x2) && (equal_slot y1 y2)
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  | IRecord (o1,r1), IRecord (o2,r2) -> 
      (o1 = o2) && (LabelMap.equal equal_slot r1 r2)
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  | ICapture x1, ICapture x2 -> Id.equal x1 x2
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  | IConstant (x1,y1), IConstant (x2,y2) -> 
      (Id.equal x1 x2) && (Types.equal_const y1 y2)
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  | _ -> false
and equal_slot s1 s2 =
  ((s1.gen1 = !gen) && (s2.gen2 = !gen) && (s1.rank1 = s2.rank2))
  ||
  ((s1.gen1 <> !gen) && (s2.gen2 <> !gen) && (
     incr rank;
     s1.rank1 <- !rank; s1.gen1 <- !gen;
     s2.rank2 <- !rank; s2.gen2 <- !gen;
     equal_descr (descr s1) (descr s2)
   ))
  
module Arg = struct
  type t = slot
      
  let hash s =
    match s.hash with
      | Some h -> h
      | None ->
	  incr gen; rank := 0; 
	  let h = hash_slot s in
	  s.hash <- Some h;
	  h
	    
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  let equal s1 s2 = 
    (s1 == s2) || 
    (incr gen; rank := 0; 
     let e = equal_slot s1 s2 in
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(*     if e then Printf.eprintf "Recursive hash-consig: Equal\n";  *)
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     e)
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end
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module SlotTable = Hashtbl.Make(Arg)
  
let rec fv_slot s =
  match s.fv with
    | Some x -> x
    | None ->
	if s.gen1 = !gen then IdSet.empty 
	else (s.gen1 <- !gen; fv_descr (descr s))
and fv_descr = function
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  | IType _ -> IdSet.empty
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  | IOr (d1,d2)
  | IAnd (d1,d2)  
  | IDiff (d1,d2) -> IdSet.cup (fv_descr d1) (fv_descr d2)
  | IOptional d -> fv_descr d
  | ITimes (s1,s2)  
  | IXml (s1,s2)  
  | IArrow (s1,s2) -> IdSet.cup (fv_slot s1) (fv_slot s2)
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  | IRecord (o,r) -> 
      List.fold_left IdSet.cup IdSet.empty (LabelMap.map_to_list fv_slot r)
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  | ICapture x | IConstant (x,_) -> IdSet.singleton x
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let compute_fv s =
  match s.fv with
    | Some x -> ()
    | None ->
	incr gen;
	let x = fv_slot s in
	s.fv <- Some x
	  
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let todo_fv = ref []
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let mk () =   
  let s = 
    { d = None;
      fv = None;
      hash = None;
      rank1 = 0; rank2 = 0;
      gen1 = 0; gen2 = 0 } in
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  todo_fv := s :: !todo_fv;
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  s
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let flush_fv () =
  List.iter compute_fv !todo_fv;
  todo_fv := []
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let compile_slot_hash = DerecursTable.create 67
let compile_hash = DerecursTable.create 67

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let defs = ref []
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let rec compile p =
  try DerecursTable.find compile_hash p
  with Not_found ->
    let c = real_compile p in
    DerecursTable.replace compile_hash p c;
    c
and real_compile = function
  | PAlias v ->
      if v.ploop then
	raise_loc_generic v.ploc ("Unguarded recursion on type/pattern");
      v.ploop <- true;
      let r = match v.pdescr with Some x -> compile x | _ -> assert false in
      v.ploop <- false;
      r
  | PType t -> IType t
  | POr (t1,t2) -> IOr (compile t1, compile t2)
  | PAnd (t1,t2) -> IAnd (compile t1, compile t2)
  | PDiff (t1,t2) -> IDiff (compile t1, compile t2)
  | PTimes (t1,t2) -> ITimes (compile_slot t1, compile_slot t2)
  | PXml (t1,t2) -> IXml (compile_slot t1, compile_slot t2)
  | PArrow (t1,t2) -> IArrow (compile_slot t1, compile_slot t2)
  | POptional t -> IOptional (compile t)
  | PRecord (o,r) ->  IRecord (o, LabelMap.map compile_slot r)
  | PConstant (x,v) -> IConstant (x,v)
  | PCapture x -> ICapture x
  | PRegexp (r,q) -> compile_regexp r q
and compile_regexp r q =
  let memo = RE.create 17 in
  let rec aux accu r q =
    if RE.mem memo (r,q) then accu
    else (
      RE.add memo (r,q) ();
      match r with
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	| PEpsilon -> 
	    (match q with 
	       | PRegexp (r,q) -> aux accu r q 
	       | _ -> (compile q) :: accu)
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	| PElem p -> ITimes (compile_slot p, compile_slot q) :: accu
	| PSeq (r1,r2) -> aux accu r1 (PRegexp (r2,q))
	| PAlt (r1,r2) -> aux (aux accu r1 q) r2 q
	| PStar r1 -> aux (aux accu r1 (PRegexp (r,q))) PEpsilon q
	| PWeakStar r1 -> aux (aux accu PEpsilon q) r1 (PRegexp (r,q))
    )
  in
  let accu = aux [] r q in
  match accu with
    | [] -> assert false
    | p::l -> List.fold_left (fun acc p -> IOr (p,acc)) p l
and compile_slot p =
  try DerecursTable.find compile_slot_hash p
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  with Not_found ->
    let s = mk () in
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    defs := (s,p) :: !defs;
    DerecursTable.add compile_slot_hash p s;
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    s
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let rec flush_defs () = 
  match !defs with
    | [] -> ()
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    | (s,p)::t -> defs := t; s.d <- Some (compile p); flush_defs ()
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let typ_nodes = SlotTable.create 67
let pat_nodes = SlotTable.create 67
		  
let rec typ = function
  | IType t -> t
  | IOr (s1,s2) -> Types.cup (typ s1) (typ s2)
  | IAnd (s1,s2) ->  Types.cap (typ s1) (typ s2)
  | IDiff (s1,s2) -> Types.diff (typ s1) (typ s2)
  | ITimes (s1,s2) -> Types.times (typ_node s1) (typ_node s2)
  | IXml (s1,s2) -> Types.xml (typ_node s1) (typ_node s2)
  | IArrow (s1,s2) -> Types.arrow (typ_node s1) (typ_node s2)
  | IOptional s -> Types.Record.or_absent (typ s)
  | IRecord (o,r) -> Types.record' (o, LabelMap.map typ_node r)
  | ICapture x | IConstant (x,_) -> assert false
      
and typ_node s : Types.node =
  try SlotTable.find typ_nodes s
  with Not_found ->
    let x = Types.make () in
    SlotTable.add typ_nodes s x;
    Types.define x (typ (descr s));
    x
      
let rec pat d : Patterns.descr =
  if IdSet.is_empty (fv_descr d)
  then Patterns.constr (typ d)
  else pat_aux d
    
    
and pat_aux = function
  | IOr (s1,s2) -> Patterns.cup (pat s1) (pat s2)
  | IAnd (s1,s2) -> Patterns.cap (pat s1) (pat s2)
  | IDiff (s1,s2) when IdSet.is_empty (fv_descr s2) ->
      let s2 = Types.neg (typ s2) in
      Patterns.cap (pat s1) (Patterns.constr s2)
  | IDiff _ ->
      raise (Patterns.Error "Difference not allowed in patterns")
  | ITimes (s1,s2) -> Patterns.times (pat_node s1) (pat_node s2)
  | IXml (s1,s2) -> Patterns.xml (pat_node s1) (pat_node s2)
  | IOptional _ -> 
      raise (Patterns.Error "Optional field not allowed in record patterns")
  | IRecord (o,r) ->
      let pats = ref [] in
      let aux l s = 
	if IdSet.is_empty (fv_slot s) then typ_node s
	else
	  ( pats := Patterns.record l (pat_node s) :: !pats;
	    Types.any_node )
      in
      let constr = Types.record' (o,LabelMap.mapi aux r) in
      List.fold_left Patterns.cap (Patterns.constr constr) !pats
	(* TODO: can avoid constr when o=true, and all fields have fv *)
  | ICapture x -> Patterns.capture x
  | IConstant (x,c) -> Patterns.constant x c
  | IArrow _ ->
      raise (Patterns.Error "Arrow not allowed in patterns")
  | IType _ -> assert false
      
and pat_node s : Patterns.node =
  try SlotTable.find pat_nodes s
  with Not_found ->
    let x = Patterns.make (fv_slot s) in
    SlotTable.add pat_nodes s x;
    Patterns.define x (pat (descr s));
    x
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575
let register_types glb b =
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  List.iter 
    (fun (v,p) ->
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       if TypeEnv.mem v glb.tenv_names
       then raise_loc_generic p.loc ("Multiple definition for type " ^ (U.to_string v))
580
    ) b;
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  let glb = derecurs_def glb b in
  let b = List.map (fun (v,p) -> (v,p,compile (derecurs glb p))) b in
  flush_defs ();
  flush_fv ();
  let b = 
    List.map 
      (fun (v,p,s) -> 
	 if not (IdSet.is_empty (fv_descr s)) then
	   raise_loc_generic p.loc 
	     "Capture variables are not allowed in types";
	 let t = typ s in
	 if (p.loc <> noloc) && (Types.is_empty t) then
	   warning p.loc 
	     ("This definition yields an empty type for " ^ (U.to_string v));
	 (v,t)) b in
  List.iter (fun (v,t) -> Types.Print.register_global v t) b;
  glb

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let register_ns glb p ns =
600
  { glb with tenv_nspref = Ns.add_prefix p ns glb.tenv_nspref }
601

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let dump_types ppf glb =
603
  TypeEnv.iter (fun v _ -> Format.fprintf ppf " %a" U.print v) glb.tenv_names
604

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let dump_ns ppf glb =
  Ns.dump_table ppf glb.tenv_nspref

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let do_typ loc r = 
  let s = compile_slot r in
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  flush_defs ();
  flush_fv ();
  if IdSet.is_empty (fv_slot s) then typ_node s
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  else raise_loc_generic loc "Capture variables are not allowed in types"
   
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let typ glb p =
  do_typ p.loc (derecurs glb p)
617
    
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let pat glb p = 
  let s = compile_slot (derecurs glb p) in
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  flush_defs ();
  flush_fv ();
  try pat_node s
  with Patterns.Error e -> raise_loc_generic p.loc e
624
    | Location (loc,_,exn) when loc = noloc -> raise (Location (p.loc, `Full, exn))
625
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(* II. Build skeleton *)

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type op = [ `Unary of tenv -> Typed.unary_op | `Binary of tenv -> Typed.binary_op ]
let op_table : (string,op) Hashtbl.t = Hashtbl.create 31
let register_unary_op s f = Hashtbl.add op_table s (`Unary f)
let register_binary_op s f = Hashtbl.add op_table s (`Binary f)
let find_op s = Hashtbl.find op_table s


637
module Fv = IdSet
638

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type branch = Branch of Typed.branch * branch list

let cur_branch : branch list ref = ref []
642

643
let exp loc fv e =
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  fv,
  { Typed.exp_loc = loc;
646
    Typed.exp_typ = Types.empty;
647
    Typed.exp_descr = e;
648
  }
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let rec expr glb loc = function
  | LocatedExpr (loc,e) -> expr glb loc e
653
  | Forget (e,t) ->
654
      let (fv,e) = expr glb loc e and t = typ glb t in
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      exp loc fv (Typed.Forget (e,t))
  | Var s -> 
      exp loc (Fv.singleton s) (Typed.Var s)
  | Apply (e1,e2) -> 
659
      let (fv1,e1) = expr glb loc e1 and (fv2,e2) = expr glb loc e2 in
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      exp loc (Fv.cup fv1 fv2) (Typed.Apply (e1,e2))
  | Abstraction a ->
662
      let iface = List.map (fun (t1,t2) -> (typ glb t1, typ glb t2)) 
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		    a.fun_iface in
      let t = List.fold_left 
		(fun accu (t1,t2) -> Types.cap accu (Types.arrow t1 t2)) 
		Types.any iface in
      let iface = List.map 
		    (fun (t1,t2) -> (Types.descr t1, Types.descr t2)) 
		    iface in
670
      let (fv0,body) = branches glb a.fun_body in
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      let fv = match a.fun_name with
	| None -> fv0
	| Some f -> Fv.remove f fv0 in
      let e = Typed.Abstraction 
		{ Typed.fun_name = a.fun_name;
		  Typed.fun_iface = iface;
		  Typed.fun_body = body;
		  Typed.fun_typ = t;
		  Typed.fun_fv = fv
		} in
      exp loc fv e
  | Cst c -> 
683
      exp loc Fv.empty (Typed.Cst (const glb loc c))
684
  | Pair (e1,e2) ->
685
      let (fv1,e1) = expr glb loc e1 and (fv2,e2) = expr glb loc e2 in
686
687
      exp loc (Fv.cup fv1 fv2) (Typed.Pair (e1,e2))
  | Xml (e1,e2) ->
688
      let (fv1,e1) = expr glb loc e1 and (fv2,e2) = expr glb loc e2 in
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      exp loc (Fv.cup fv1 fv2) (Typed.Xml (e1,e2))
  | Dot (e,l) ->
691
      let (fv,e) = expr glb loc e in
692
      exp loc fv (Typed.Dot (e,parse_label glb loc l))
693
  | RemoveField (e,l) ->
694
      let (fv,e) = expr glb loc e in
695
      exp loc fv (Typed.RemoveField (e,parse_label glb loc l))
696
697
  | RecordLitt r -> 
      let fv = ref Fv.empty in
698
      let r = parse_record glb loc
699
		(fun e -> 
700
		   let (fv2,e) = expr glb loc e 
701
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703
		   in fv := Fv.cup !fv fv2; e)
		r in
      exp loc !fv (Typed.RecordLitt r)
704
  | String (i,j,s,e) ->
705
      let (fv,e) = expr glb loc e in
706
      exp loc fv (Typed.String (i,j,s,e))
707
  | Op (op,le) ->
708
      let (fvs,ltes) = List.split (List.map (expr glb loc) le) in
709
      let fv = List.fold_left Fv.cup Fv.empty fvs in
710
      (try
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	 (match (ltes,find_op op) with
	    | [e], `Unary op -> exp loc fv (Typed.UnaryOp (op glb, e))
	    | [e1;e2], `Binary op -> exp loc fv (Typed.BinaryOp (op glb, e1,e2))
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716
	    | _ -> assert false)
       with Not_found -> assert false)

717
  | Match (e,b) -> 
718
719
      let (fv1,e) = expr glb loc e
      and (fv2,b) = branches glb b in
720
      exp loc (Fv.cup fv1 fv2) (Typed.Match (e, b))
721
  | Map (e,b) ->
722
723
      let (fv1,e) = expr glb loc e
      and (fv2,b) = branches glb b in
724
725
      exp loc (Fv.cup fv1 fv2) (Typed.Map (e, b))
  | Transform (e,b) ->
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727
      let (fv1,e) = expr glb loc e
      and (fv2,b) = branches glb b in
728
      exp loc (Fv.cup fv1 fv2) (Typed.Transform (e, b))
729
  | Xtrans (e,b) ->
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731
      let (fv1,e) = expr glb loc e
      and (fv2,b) = branches glb b in
732
      exp loc (Fv.cup fv1 fv2) (Typed.Xtrans (e, b))
733
  | Validate (e,schema,elt) ->
734
      let (fv,e) = expr glb loc e in
735
      exp loc fv (Typed.Validate (e, schema, elt))
736
  | Try (e,b) ->
737
738
      let (fv1,e) = expr glb loc e
      and (fv2,b) = branches glb b in
739
      exp loc (Fv.cup fv1 fv2) (Typed.Try (e, b))
740
  | NamespaceIn (pr,ns,e) ->
741
      let glb = register_ns glb pr ns in
742
      expr glb loc e
743

744
	      
745
  and branches glb b = 
746
    let fv = ref Fv.empty in
747
    let accept = ref Types.empty in
748
    let branch (p,e) = 
749
750
      let cur_br = !cur_branch in
      cur_branch := [];
751
      let (fv2,e) = expr glb noloc e in
752
      let br_loc = merge_loc p.loc e.Typed.exp_loc in
753
      let p = pat glb p in
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761
762
      let fv2 = Fv.diff fv2 (Patterns.fv p) in
      fv := Fv.cup !fv fv2;
      accept := Types.cup !accept (Types.descr (Patterns.accept p));
      let br = 
	{ 
	  Typed.br_loc = br_loc;
	  Typed.br_used = br_loc = noloc;
	  Typed.br_pat = p;
	  Typed.br_body = e } in
763
      cur_branch := Branch (br, !cur_branch) :: cur_br;
764
765
      br in
    let b = List.map branch b in
766
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768
769
    (!fv, 
     { 
       Typed.br_typ = Types.empty; 
       Typed.br_branches = b; 
770
771
       Typed.br_accept = !accept;
       Typed.br_compiled = None;
772
773
     } 
    )
774

775
let expr glb = expr glb noloc
776

777
778
779
let let_decl glb p e =
  let (_,e) = expr glb e in
  { Typed.let_pat = pat glb p;
780
781
782
    Typed.let_body = e;
    Typed.let_compiled = None }

783
784
785
786
787

(* Hide global "typing/parsing" environment *)

let glb = State.ref "Typer.glb_env" 
	    { tenv_names = TypeEnv.empty;
788
	      tenv_nspref = Ns.empty_table;
789
790
791
792
793
794
795
	      tenv_loc = noloc }

let pat p = pat !glb p
let typ t = typ !glb t
let expr e = expr !glb e
let let_decl p e = let_decl !glb p e

796
797
let register_global_types l = glb := register_types !glb l
let dump_global_types ppf = dump_types ppf !glb
798

799
800
let register_global_ns p ns = glb := register_ns !glb p ns
let dump_global_ns ppf = dump_ns ppf !glb
801

802
803
let set_ns_table_for_printer () = Ns.InternalPrinter.set_table !glb.tenv_nspref

804
805
806
(* III. Type-checks *)

type env = Types.descr Env.t
807
808
809

open Typed

810
811
let require loc t s = 
  if not (Types.subtype t s) then raise_loc loc (Constraint (t, s))
812

813
814
815
let check loc t s = 
  require loc t s; t

816
817
818
819
820
let check_str loc ofs t s = 
  if not (Types.subtype t s) then raise_loc_str loc ofs (Constraint (t, s));
  t

let should_have loc constr s = 
821
822
  raise_loc loc (ShouldHave (constr,s))

823
824
825
let should_have_str loc ofs constr s = 
  raise_loc_str loc ofs (ShouldHave (constr,s))

826
827
828
829
830
831
832
833
834
835
836
let flatten loc arg constr precise =
  let constr' = Sequence.star 
		  (Sequence.approx (Types.cap Sequence.any constr)) in
  let sconstr' = Sequence.star constr' in
  let exact = Types.subtype constr' constr in
  if exact then
    let t = arg sconstr' precise in
    if precise then Sequence.flatten t else constr
  else
    let t = arg sconstr' true in
    Sequence.flatten t
837

838
839
let rec type_check env e constr precise = 
  let d = type_check' e.exp_loc env e.exp_descr constr precise in
840
  let d = if precise then d else constr in
841
842
843
  e.exp_typ <- Types.cup e.exp_typ d;
  d

844
and type_check' loc env e constr precise = match e with
845
846
847
  | Forget (e,t) ->
      let t = Types.descr t in
      ignore (type_check env e t false);
848
849
      check loc t constr

850
  | Abstraction a ->
851
852
853
      let t =
	try Types.Arrow.check_strenghten a.fun_typ constr 
	with Not_found -> 
854
855
	  should_have loc constr
	    "but the interface of the abstraction is not compatible"
856
      in
857
858
859
      let env = match a.fun_name with
	| None -> env
	| Some f -> Env.add f a.fun_typ env in
860
861
      List.iter 
	(fun (t1,t2) ->
862
863
864
	   let acc = a.fun_body.br_accept in 
	   if not (Types.subtype t1 acc) then
	     raise_loc loc (NonExhaustive (Types.diff t1 acc));
865
	   ignore (type_check_branches loc env t1 a.fun_body t2 false)
866
867
	) a.fun_iface;
      t
868

869
870
  | Match (e,b) ->
      let t = type_check env e b.br_accept true in
871
      type_check_branches loc env t b constr precise
872
873
874

  | Try (e,b) ->
      let te = type_check env e constr precise in
875
      let tb = type_check_branches loc env Types.any b constr precise in
876
      Types.cup te tb
877

878
879
  | Pair (e1,e2) ->
      type_check_pair loc env e1 e2 constr precise
880

881
882
  | Xml (e1,e2) ->
      type_check_pair ~kind:`XML loc env e1 e2 constr precise
883

884
  | RecordLitt r ->
885
886
887
888
889
890
891
892
      type_record loc env r constr precise

  | Map (e,b) ->
      type_map loc env false e b constr precise

  | Transform (e,b) ->
      flatten loc (type_map loc env true e b) constr precise

893
894
895
896
  | Apply (e1,e2) ->
      let t1 = type_check env e1 Types.Arrow.any true in
      let t1 = Types.Arrow.get t1 in
      let dom = Types.Arrow.domain t1 in
897
898
899
900
901
902
903
      let res =
	if Types.Arrow.need_arg t1 then
	  let t2 = type_check env e2 dom true in
	  Types.Arrow.apply t1 t2
	else
	  (ignore (type_check env e2 dom false); Types.Arrow.apply_noarg t1)
      in
904
905
906
      check loc res constr

  | UnaryOp (o,e) ->
907
908
      let t = o.un_op_typer loc 
		(type_check env e) constr precise in
909
910
911
      check loc t constr

  | BinaryOp (o,e1,e2) ->
912
913
914
      let t = o.bin_op_typer loc 
		(type_check env e1) 
		(type_check env e2) constr precise in
915
916
917
918
919
920
921
922
923
924
925
      check loc t constr

  | Var s -> 
      let t = 
	try Env.find s env
	with Not_found -> raise_loc loc (UnboundId s) in
      check loc t constr
      
  | Cst c -> 
      check loc (Types.constant c) constr

926
927
928
  | String (i,j,s,e) ->
      type_check_string loc env 0 s i j e constr precise

929
930
931
932
933
934
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936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
  | Dot (e,l) ->
      let t = type_check env e Types.Record.any true in
      let t = 
        try (Types.Record.project t l) 
        with Not_found -> raise_loc loc (WrongLabel(t,l))
      in
      check loc t constr

  | RemoveField (e,l) ->
      let t = type_check env e Types.Record.any true in
      let t = Types.Record.remove_field t l in
      check loc t constr

  | Xtrans (e,b) ->
      let t = type_check env e Sequence.any true in
      let t = 
	Sequence.map_tree 
	  (fun t ->
	     let resid = Types.diff t b.br_accept in
	     let res = type_check_branches loc env t b Sequence.any true in
	     (res,resid)
	  ) t in
      check loc t constr

953
954
955
956
  | Validate (e, schema_name, elt_name) ->
      ignore (type_check env e Types.any false);
      let t = fst (Hashtbl.find !schema_elements (schema_name, elt_name)) in
      check loc t constr
957

958
and type_check_pair ?(kind=`Normal) loc env e1 e2 constr precise =
959
  let rects = Types.Product.normal ~kind constr in
960
961
  if Types.Product.is_empty rects then 
    (match kind with
962
963
      | `Normal -> should_have loc constr "but it is a pair"
      | `XML -> should_have loc constr "but it is an XML element");
964
  let need_s = Types.Product.need_second rects in
965
966
967
968
969
  let t1 = type_check env e1 (Types.Product.pi1 rects) (precise || need_s) in
  let c2 = Types.Product.constraint_on_2 rects t1 in
  if Types.is_empty c2 then 
    raise_loc loc (ShouldHave2 (constr,"but the first component has type",t1));
  let t2 = type_check env e2 c2 precise in
970

971
  if precise then 
972
973
974
    match kind with
      | `Normal -> Types.times (Types.cons t1) (Types.cons t2)
      | `XML -> Types.xml (Types.cons t1) (Types.cons t2)
975
976
977
  else
    constr

978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
and type_check_string loc env ofs s i j e constr precise =
  if U.equal_index i j then type_check env e constr precise
  else
    let rects = Types.Product.normal constr in
    if Types.Product.is_empty rects 
    then should_have_str loc ofs constr "but it is a string"
    else
      let need_s = Types.Product.need_second rects in
      let (ch,i') = U.next s i in
      let ch = Chars.mk_int ch in
      let tch = Types.constant (Types.Char ch) in
      let t1 = check_str loc ofs tch (Types.Product.pi1 rects) in
      let c2 = Types.Product.constraint_on_2 rects t1 in
      let t2 = type_check_string loc env (ofs + 1) s i' j e c2 precise in
      if precise then Types.times (Types.cons t1) (Types.cons t2)
      else constr

995
996
997
998
999
1000
1001
1002
1003
1004
1005
and type_record loc env r constr precise =
(* try to get rid of precise = true for values of fields *)
(* also: the use equivalent of need_second to optimize... *)
  if not (Types.Record.has_record constr) then
    should_have loc constr "but it is a record";
  let (rconstr,res) = 
    List.fold_left
      (fun (rconstr,res) (l,e) ->
	 (* could compute (split l e) once... *)
	 let pi = Types.Record.project_opt rconstr l in
	 if Types.is_empty pi then 
1006
	   (let l = Label.to_string (LabelPool.value l) in
1007
1008
1009
1010
1011
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1020
	    should_have loc constr
	      (Printf.sprintf "Field %s is not allowed here." l));
	 let t = type_check env e pi true in
	 let rconstr = Types.Record.condition rconstr l t in
	 let res = (l,Types.cons t) :: res in
	 (rconstr,res)
      ) (constr, []) (LabelMap.get r)
  in
  if not (Types.Record.has_empty_record rconstr) then
    should_have loc constr "More fields should be present";
  let t = 
    Types.record' (false, LabelMap.from_list (fun _ _ -> assert false) res)
  in
  check loc t constr
1021

1022

1023
and type_check_branches loc env targ brs constr precise =
1024
  if Types.is_empty targ then Types.empty
1025
1026
  else (
    brs.br_typ <- Types.cup brs.br_typ targ;
1027
    branches_aux loc env targ 
1028
1029
      (if precise then Types.empty else constr) 
      constr precise brs.br_branches
1030
  )
1031
    
1032
and branches_aux loc env targ tres constr precise = function
1033
  | [] -> tres
1034
1035
1036
1037
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1039
  | b :: rem ->
      let p = b.br_pat in
      let acc = Types.descr (Patterns.accept p) in

      let targ' = Types.cap targ acc in
      if Types.is_empty targ' 
1040
      then branches_aux loc env targ tres constr precise rem
1041
1042
1043
1044
1045
1046
      else 
	( b.br_used <- true;
	  let res = Patterns.filter targ' p in
	  let env' = List.fold_left 
		       (fun env (x,t) -> Env.add x (Types.descr t) env) 
		       env res in
1047
1048
	  let t = type_check env' b.br_body constr precise in
	  let tres = if precise then Types.cup t tres else tres in
1049
1050
	  let targ'' = Types.diff targ acc in
	  if (Types.non_empty targ'') then 
1051
	    branches_aux loc env targ'' tres constr precise rem 
1052
1053
	  else
	    tres
1054
	)
1055

1056
1057
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1059
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and type_map loc env def e b constr precise = 
  let acc = if def then Sequence.any else Sequence.star b.br_accept in
  let t = type_check env e acc true in

  let constr' = Sequence.approx (Types.cap Sequence.any constr) in
  let exact = Types.subtype (Sequence.star constr') constr in
  (* Note: 
     - could be more precise by integrating the decomposition
     of constr inside Sequence.map.
  *)
  let res = 
    Sequence.map 
      (fun t ->
	 let res = 
	   type_check_branches loc env t b constr' (precise || (not exact)) in
	 if def && not (Types.subtype t b.br_accept) 
	 then Types.cup res Sequence.nil_type
	 else res)
      t in
  if exact then res else check loc res constr

1077
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1079
1080
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1085
and type_let_decl env l =
  let acc = Types.descr (Patterns.accept l.let_pat) in
  let t = type_check env l.let_body acc true in
  let res = Patterns.filter t l.let_pat in
  List.map (fun (x,t) -> (x, Types.descr t)) res

and type_rec_funs env l =
  let types = 
    List.fold_left
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1088
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1090
      (fun accu -> function  
	 | { exp_descr=Abstraction { fun_typ = t; fun_name = Some f } } ->
	     (f,t) :: accu
	 | _ -> assert false
      ) [] l
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1092
  in
  let env' = List.fold_left (fun env (x,t) -> Env.add x t env) env types in
1093
  List.iter (fun e -> ignore (type_check env' e Types.any false)) l;
1094
1095
  types

1096
1097

let rec unused_branches b =
1098
  List.iter
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    (fun (Branch (br,s)) -> 
       if not br.br_used 
       then warning br.br_loc "This branch is not used"
       else unused_branches s
    )
    b

let report_unused_branches () =
  unused_branches !cur_branch;
  cur_branch := []
1109

1110
1111
  (* Schema stuff from now on ... *)

1112