types.ml 60.2 KB
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open Ident
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open Encodings
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let count = ref 0
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let () =
  Stats.register Stats.Summary
    (fun ppf -> Format.fprintf ppf "Allocated type nodes:%i@\n" !count)

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(* 
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To be sure not to use generic comparison ...
*)
let (=) : int -> int -> bool = (==)
let (<) : int -> int -> bool = (<)
let (<=) : int -> int -> bool = (<=)
let (<>) : int -> int -> bool = (<>)
let compare = 1

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type const = 
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  | Integer of Intervals.V.t
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  | Atom of Atoms.V.t
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  | Var of Atoms.V.t
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  | Char of Chars.V.t
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  | Pair of const * const
  | Xml of const * const
  | Record of const label_map
  | String of U.uindex * U.uindex * U.t * const
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type service_params =
  | TProd of service_params * service_params
  | TOption of service_params 
  | TList of string * service_params
  | TSet of service_params
  | TSum of service_params * service_params
  | TString of string
  | TInt of string
  | TInt32 of string
  | TInt64 of string
  | TFloat of string 
  | TBool of string
  | TFile of string
      (* | TUserType of string * (string -> 'a) * ('a -> string) *)
  | TCoord of string 
  | TCoordv of service_params * string
  | TESuffix of string 
  | TESuffixs of string
      (*  | TESuffixu of (string * (string -> 'a) * ('a -> string)) *)
  | TSuffix of (bool * service_params)
  | TUnit 
  | TAny
  | TConst of string;;

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module Const = struct
  type t = const

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  let check _ = ()
  let dump ppf _ = Format.fprintf ppf "<Types.Const.t>"
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  let rec compare c1 c2 = match (c1,c2) with
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    | Integer x, Integer y -> Intervals.V.compare x y
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    | Integer _, _ -> -1
    | _, Integer _ -> 1
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    | Atom x, Atom y -> Atoms.V.compare x y
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    | Atom _, _ -> -1
    | _, Atom _ -> 1
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    | Var x, Var y -> Atoms.V.compare x y
    | Var _, _ -> -1
    | _, Var _ -> 1

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    | Char x, Char y -> Chars.V.compare x y
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    | Char _, _ -> -1
    | _, Char _ -> 1
    | Pair (x1,x2), Pair (y1,y2) ->
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	let c = compare x1 y1 in
	if c <> 0 then c else compare x2 y2
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    | Pair (_,_), _ -> -1
    | _, Pair (_,_) -> 1
    | Xml (x1,x2), Xml (y1,y2) ->
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	let c = compare x1 y1 in
	if c <> 0 then c else compare x2 y2
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    | Xml (_,_), _ -> -1
    | _, Xml (_,_) -> 1
    | Record x, Record y ->
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	LabelMap.compare compare x y
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    | Record _, _ -> -1
    | _, Record _ -> 1
    | String (i1,j1,s1,r1), String (i2,j2,s2,r2) ->
	let c = Pervasives.compare i1 i2 in if c <> 0 then c 
	else let c = Pervasives.compare j1 j2 in if c <> 0 then c
	else let c = U.compare s1 s2 in if c <> 0 then c (* Should compare
							    only the substring *)
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	else compare r1 r2

  let rec hash = function
    | Integer x -> 1 + 17 * (Intervals.V.hash x)
    | Atom x -> 2 + 17 * (Atoms.V.hash x)
    | Char x -> 3 + 17 * (Chars.V.hash x)
    | Pair (x,y) -> 4 + 17 * (hash x) + 257 * (hash y)
    | Xml (x,y) -> 5 + 17 * (hash x) + 257 * (hash y)
    | Record x -> 6 + 17 * (LabelMap.hash hash x)
    | String (i,j,s,r) -> 7 + 17 * (U.hash s) + 257 * hash r
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    | Var x -> 7 + 17 * (Atoms.V.hash x)
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      (* Note: improve hash for String *)
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  let equal c1 c2 = compare c1 c2 = 0
end
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module Abstract =
struct
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  module T = Custom.String
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  type abs = T.t

  module V =
  struct
    type t = abs * Obj.t
  end

  include SortedList.FiniteCofinite(T)

  let print = function
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    | Finite l -> List.map (fun x ppf -> Format.fprintf ppf "!%s" x) l
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    | Cofinite l ->       
	[ fun ppf ->
	  Format.fprintf ppf "@[Abstract";
	  List.iter (fun x -> Format.fprintf ppf " \\@ !%s" x) l;
	  Format.fprintf ppf "@]" ]
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  let contains_sample s t = match s,t with
    | None, Cofinite _ -> true
    | None, Finite _ -> false
    | Some s, t -> contains s t
    

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end


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type pair_kind = [ `Normal | `XML ]

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module rec Descr : 
sig
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  type s = {
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    atoms : Atoms.t;
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    vars  : Atoms.t;
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    ints  : Intervals.t;
    chars : Chars.t;
    times : BoolPair.t;
    xml   : BoolPair.t;
    arrow : BoolPair.t;
    record: BoolRec.t;
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    abstract: Abstract.t;
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    absent: bool
  }
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  include Custom.T with type t = s
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  val empty: t
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end =
struct
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  type s = {
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    atoms : Atoms.t;
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    vars  : Atoms.t;
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    ints  : Intervals.t;
    chars : Chars.t;
    times : BoolPair.t;
    xml   : BoolPair.t;
    arrow : BoolPair.t;
    record: BoolRec.t;
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    abstract: Abstract.t;
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    absent: bool
  }
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  type t = s
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  let print_lst ppf =
    List.iter (fun f -> f ppf; Format.fprintf ppf " |")

  let dump ppf d =
    Format.fprintf ppf "<types atoms(%a) times(%a) record(%a) xml(%a)>"
      print_lst (Atoms.print d.atoms)
      BoolPair.dump d.times
      BoolRec.dump d.record
      BoolPair.dump d.xml
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  let empty = { 
    times = BoolPair.empty; 
    xml   = BoolPair.empty; 
    arrow = BoolPair.empty; 
    record= BoolRec.empty;
    ints  = Intervals.empty;
    atoms = Atoms.empty;
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    vars = Atoms.empty;
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    chars = Chars.empty;
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    abstract = Abstract.empty;
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    absent= false;
  }

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  let equal a b =
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    (a == b) || (
      (Atoms.equal a.atoms b.atoms) &&
      (Chars.equal a.chars b.chars) &&
      (Intervals.equal a.ints  b.ints) &&
      (BoolPair.equal a.times b.times) &&
      (BoolPair.equal a.xml b.xml) &&
      (BoolPair.equal a.arrow b.arrow) &&
      (BoolRec.equal a.record b.record) &&
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      (Abstract.equal a.abstract b.abstract) &&
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      (a.absent == b.absent)
    )
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  let compare a b =
    if a == b then 0 
    else let c = Atoms.compare a.atoms b.atoms in if c <> 0 then c
    else let c = Chars.compare a.chars b.chars in if c <> 0 then c
    else let c = Intervals.compare a.ints b.ints in if c <> 0 then c
    else let c = BoolPair.compare a.times b.times in if c <> 0 then c
    else let c = BoolPair.compare a.xml b.xml in if c <> 0 then c
    else let c = BoolPair.compare a.arrow b.arrow in if c <> 0 then c
    else let c = BoolRec.compare a.record b.record in if c <> 0 then c
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    else let c = Abstract.compare a.abstract b.abstract in if c <> 0 then c
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    else if a.absent && not b.absent then -1
    else if b.absent && not a.absent then 1
    else 0
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  let hash a =
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    let accu = Chars.hash a.chars in
    let accu = 17 * accu + Intervals.hash a.ints in
    let accu = 17 * accu + Atoms.hash a.atoms in
    let accu = 17 * accu + BoolPair.hash a.times in
    let accu = 17 * accu + BoolPair.hash a.xml in
    let accu = 17 * accu + BoolPair.hash a.arrow in
    let accu = 17 * accu + BoolRec.hash a.record in
    let accu = 17 * accu + Abstract.hash a.abstract in
    let accu = if a.absent then accu+5 else accu in
    accu
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  let check a =
    Chars.check a.chars;
    Intervals.check a.ints;
    Atoms.check a.atoms;
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    Atoms.check a.vars;
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    BoolPair.check a.times;
    BoolPair.check a.xml;
    BoolPair.check a.arrow;
    BoolRec.check a.record;
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    Abstract.check a.abstract;
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    ()


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end
and Node :
sig
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  type t = { id : int; cu: Compunit.t; mutable descr : Descr.t }
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  val dump: Format.formatter -> t -> unit
  val check: t -> unit
  val equal: t -> t -> bool
  val hash: t -> int
  val compare:t -> t -> int
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  val mk: int -> Descr.t -> t
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end =
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struct
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  type t = { id : int; cu: Compunit.t; mutable descr : Descr.t }
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  let check n = ()
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  let dump ppf n = Format.fprintf ppf "X%i" n.id
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  let hash x = x.id + Compunit.hash x.cu
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  let compare x y = 
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    let c = x.id - y.id in if c = 0 then Compunit.compare x.cu y.cu else c
  let equal x y = x==y || (x.id == y.id && (Compunit.equal x.cu y.cu))
  let mk id d = { id = id; cu = Compunit.current (); descr = d }
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end

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(* It is also possible to use Boolean instead of Bool here;
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   need to analyze when each one is more efficient *)
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and BoolPair : Bool.S with type elem = Node.t * Node.t = 
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(*Bool.Simplify*)(Bool.Make)(Custom.Pair(Node)(Node))
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and BoolRec : Bool.S with type elem = bool * Node.t label_map =
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(*Bool.Simplify*)(Bool.Make)(Custom.Pair(Custom.Bool)(LabelSet.MakeMap(Node)))
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module DescrHash = Hashtbl.Make(Descr)
module DescrMap = Map.Make(Descr)
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module DescrSet = Set.Make(Descr)
module DescrSList = SortedList.Make(Descr)
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type descr = Descr.t
type node = Node.t
include Descr
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let forward_print = ref (fun _ _ -> assert false)

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let make () = 
  incr count; 
  Node.mk !count empty

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let define n d = 
  n.Node.descr <- d

let cons d = 
  incr count; 
  Node.mk !count d

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let any =  {
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  times = BoolPair.full; 
  xml   = BoolPair.full; 
  arrow = BoolPair.full; 
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  record= BoolRec.full; 
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  ints  = Intervals.any;
  atoms = Atoms.any;
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  vars = Atoms.any;
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  chars = Chars.any;
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  abstract = Abstract.any;
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  absent= false;
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}
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let non_constructed =
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  { any with  
      times = empty.times; xml = empty.xml; record = empty.record }
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let non_constructed_or_absent = 
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  { non_constructed with absent = true }
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let interval i = { empty with ints = i }
let times x y = { empty with times = BoolPair.atom (x,y) }
let xml x y = { empty with xml = BoolPair.atom (x,y) }
let arrow x y = { empty with arrow = BoolPair.atom (x,y) }
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let record label t = 
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  { empty with 
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      record = BoolRec.atom (true,LabelMap.singleton label t) }
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let record_fields (x : bool * node Ident.label_map) =
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  { empty with record = BoolRec.atom x }
let atom a = { empty with atoms = a }
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let vars a = { empty with vars = a }
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let char c = { empty with chars = c }
let abstract a = { empty with abstract = a }
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let get_abstract t = t.abstract
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let cup x y = 
  if x == y then x else {
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    times = BoolPair.cup x.times y.times;
    xml   = BoolPair.cup x.xml y.xml;
    arrow = BoolPair.cup x.arrow y.arrow;
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    record= BoolRec.cup x.record y.record;
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    ints  = Intervals.cup x.ints  y.ints;
    atoms = Atoms.cup x.atoms y.atoms;
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    vars = Atoms.cup x.vars y.vars;
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    chars = Chars.cup x.chars y.chars;
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    abstract = Abstract.cup x.abstract y.abstract;
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    absent= x.absent || y.absent;
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  }
    
let cap x y = 
  if x == y then x else {
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    times = BoolPair.cap x.times y.times;
    xml   = BoolPair.cap x.xml y.xml;
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    record= BoolRec.cap x.record y.record;
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    arrow = BoolPair.cap x.arrow y.arrow;
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    ints  = Intervals.cap x.ints  y.ints;
    atoms = Atoms.cap x.atoms y.atoms;
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    vars = Atoms.cap x.vars y.vars;
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    chars = Chars.cap x.chars y.chars;
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    abstract = Abstract.cap x.abstract y.abstract;
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    absent= x.absent && y.absent;
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  }
    
let diff x y = 
  if x == y then empty else {
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    times = BoolPair.diff x.times y.times;
    xml   = BoolPair.diff x.xml y.xml;
    arrow = BoolPair.diff x.arrow y.arrow;
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    record= BoolRec.diff x.record y.record;
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    ints  = Intervals.diff x.ints  y.ints;
    atoms = Atoms.diff x.atoms y.atoms;
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    vars = Atoms.diff x.vars y.vars;
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    chars = Chars.diff x.chars y.chars;
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    abstract = Abstract.diff x.abstract y.abstract;
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    absent= x.absent && not y.absent;
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  }
    
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(* TODO: optimize disjoint check for boolean combinations *)
let trivially_disjoint a b =
  (Chars.disjoint a.chars b.chars) &&
  (Intervals.disjoint a.ints b.ints) &&
  (Atoms.disjoint a.atoms b.atoms) &&
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  (Atoms.disjoint a.vars b.vars) &&
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  (BoolPair.trivially_disjoint a.times b.times) &&
  (BoolPair.trivially_disjoint a.xml b.xml) &&
  (BoolPair.trivially_disjoint a.arrow b.arrow) &&
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  (BoolRec.trivially_disjoint a.record b.record) &&
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  (Abstract.disjoint a.abstract b.abstract) &&
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  (not (a.absent && b.absent))
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let descr n = n.Node.descr
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let internalize n = n
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let id n = n.Node.id
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let rec constant = function
  | Integer i -> interval (Intervals.atom i)
  | Atom a -> atom (Atoms.atom a)
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  | Var a -> vars (Atoms.atom a)
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  | Char c -> char (Chars.atom c)
  | Pair (x,y) -> times (const_node x) (const_node y)
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  | Xml (x,y) -> xml (const_node x) (const_node y)
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  | Record x -> record_fields (false ,LabelMap.map const_node x)
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  | String (i,j,s,c) ->
      if U.equal_index i j then constant c
      else 
	let (ch,i') = U.next s i in
	constant (Pair (Char (Chars.V.mk_int ch), String (i',j,s,c)))
and const_node c = cons (constant c)
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let neg x = diff any x

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let any_node = cons any
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let empty_node = cons empty
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module LabelS = Set.Make(Label)
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let any_or_absent = { any with absent = true } 
let only_absent = { empty with absent = true }
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let get_record r =
  let labs accu (_,r) = 
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    List.fold_left 
      (fun accu (l,_) -> LabelS.add l accu) accu (LabelMap.get r) in
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  let extend descrs labs (o,r) =
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    let rec aux i labs r =
      match labs with
	| [] -> ()
	| l1::labs ->
	    match r with
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	      | (l2,x)::r when l1 == l2 -> 
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		  descrs.(i) <- cap descrs.(i) (descr x);
		  aux (i+1) labs r
	      | r ->
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		  if not o then 
		    descrs.(i) <- cap descrs.(i) only_absent; (* TODO:OPT *)
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		  aux (i+1) labs r
    in
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    aux 0 labs (LabelMap.get r);
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    o
  in
  let line (p,n) =
    let labels = 
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      List.fold_left labs (List.fold_left labs LabelS.empty p) n in
    let labels = LabelS.elements labels in
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    let nlab = List.length labels in
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    let mk () = Array.create nlab any_or_absent in
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    let pos = mk () in
    let opos = List.fold_left 
		 (fun accu x -> 
		    (extend pos labels x) && accu)
		 true p in
    let p = (opos, pos) in

    let n = List.map (fun x ->
			let neg = mk () in
			let o = extend neg labels x in
			(o,neg)
		     ) n in
    (labels,p,n)
  in
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  List.map line (BoolRec.get r)
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(* Subtyping algorithm *)

let diff_t d t = diff d (descr t)
let cap_t d t = cap d (descr t)
let cup_t d t = cup d (descr t)
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let cap_product any_left any_right l =
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  List.fold_left 
    (fun (d1,d2) (t1,t2) -> (cap_t d1 t1, cap_t d2 t2))
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    (any_left,any_right)
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    l
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let any_pair = { empty with times = any.times }
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let rec exists max f =
  (max > 0) && (f (max - 1) || exists (max - 1) f)

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exception NotEmpty
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module Witness = struct

  module NodeSet = Set.Make(Node)

  type witness =
    | WInt of Intervals.V.t
    | WAtom of Atoms.sample
    | WChar of Chars.V.t
    | WAbsent
    | WAbstract of Abstract.elem option

    | WPair of witness * witness * witness_slot
    | WXml of witness * witness * witness_slot
    | WRecord of witness label_map * bool * witness_slot
	(* Invariant: WAbsent cannot actually appear *)

    | WFun of (witness * witness option) list * witness_slot
  and witness_slot = 
      { mutable wnodes_in: NodeSet.t;
	mutable wnodes_out: NodeSet.t;
	mutable wuid: int }

  module WHash = Hashtbl.Make(
    struct
      type t = witness
      let hash_small = function
	| WInt i -> 17 * Intervals.V.hash i
	| WChar c -> 1 + 17 * Chars.V.hash c
	| WAtom None -> 2
	| WAtom (Some (ns,None)) -> 3 + 17 * Ns.Uri.hash ns
	| WAtom (Some (_,Some t)) -> 4 + 17 * Ns.Label.hash t
	| WAbsent -> 5
	| WAbstract None -> 6
	| WAbstract (Some t) -> 7 + 17 * Abstract.T.hash t
	| WPair (_,_,s) 
	| WXml (_,_,s)
	| WRecord (_,_,s)
	| WFun (_,s) -> 8 + 17 * s.wuid
      let hash = function
	| WPair (p1,p2,_) -> 257 * hash_small p1 + 65537 * hash_small p2
	| WXml (p1,p2,_) -> 1 + 257 * hash_small p1 + 65537 * hash_small p2
	| WRecord (r,o,_) -> 
	    (if o then 2 else 3) + 257 * LabelMap.hash hash_small r
	| WFun (f,_) ->
	    4 + 257 *
	      (Hashtbl.hash 
		 (List.map 
		    (function (x,None) -> 17 * hash_small x
		       | (x,Some y) -> 
			   1 + 17 * hash_small x + 257 * hash_small y)
		    f)
	      )
	| _ -> assert false

      let equal_small w1 w2 = match w1,w2 with
	| WInt i1, WInt i2 -> Intervals.V.equal i1 i2
	| WChar c1, WChar c2 -> Chars.V.equal c1 c2
	| WAtom None, WAtom None -> true
	| WAtom (Some (ns1,None)), WAtom (Some (ns2,None)) ->
	    Ns.Uri.equal ns1 ns2
	| WAtom (Some (_,Some t1)), WAtom (Some (_,Some t2)) ->
	    Ns.Label.equal t1 t2
	| WAbsent, WAbsent -> true
	| WAbstract None, WAbstract None -> false
	| WAbstract (Some t1), WAbstract (Some t2) -> Abstract.T.equal t1 t2
	| _ -> w1 == w2

      let equal w1 w2 = match w1,w2 with
	| WPair (p1,q1,_), WPair (p2,q2,_) 
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	| WXml (p1,q1,_), WXml (p2,q2,_) -> 
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	    equal_small p1 p2 && equal_small q1 q2
	| WRecord (r1,o1,_), WRecord (r2,o2,_) ->
	    o1 == o2 && (LabelMap.equal equal_small r1 r2)
	| WFun (f1,_), WFun (f2,_) ->
	    List.length f1 = List.length f2 &&
		List.for_all2
		(fun (x1,y1) (x2,y2) ->
		   equal_small x1 x2 && (match y1,y2 with
					   | Some y1, Some y2 -> 
					       equal_small y1 y2
					   | None, None -> true
					   | _ -> false)
		) f1 f2
	| _ -> false
    end)

  let wmemo = WHash.create 1024
  let wuid = ref 0
  let wslot () = { wuid = !wuid; wnodes_in = NodeSet.empty; 
		   wnodes_out = NodeSet.empty }


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  let () =
    Stats.register Stats.Summary
      (fun ppf -> Format.fprintf ppf "Allocated witnesses:%i@\n" !wuid)

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  let rec print_witness ppf = function
    | WInt i ->
	Format.fprintf ppf "%a" Intervals.V.print i
    | WChar c ->
	Format.fprintf ppf "%a" Chars.V.print c
    | WAtom None ->
	Format.fprintf ppf "`#:#"
    | WAtom (Some (ns,None)) ->
	Format.fprintf ppf "`%a" Ns.InternalPrinter.print_any_ns ns
    | WAtom (Some (_,Some t)) ->
	Format.fprintf ppf "`%a" Ns.Label.print_attr t
    | WPair (w1,w2,_) -> 
	Format.fprintf ppf "(%a,%a)" print_witness w1 print_witness w2
    | WXml (w1,w2,_) -> 
	Format.fprintf ppf "XML(%a,%a)" print_witness w1 print_witness w2
    | WRecord (ws,o,_) ->
	Format.fprintf ppf "{";
	LabelMap.iteri
	  (fun l w -> Format.fprintf ppf " %a=%a" 
	     Label.print_attr l print_witness w)
	  ws;
	if o then Format.fprintf ppf " ..";
	Format.fprintf ppf " }"
    | WFun (f,_) ->
	Format.fprintf ppf "FUN{";
	List.iter (fun (x,y) ->
		     Format.fprintf ppf " %a->" print_witness x;
		     match y with
		       | None -> Format.fprintf ppf "#"
		       | Some y -> print_witness ppf y) f;
	Format.fprintf ppf " }"
    | WAbstract None ->
	Format.fprintf ppf "Abstract(..)"
    | WAbstract (Some s) ->
	Format.fprintf ppf "Abstract(%s)" s
    | WAbsent ->
	Format.fprintf ppf "Absent"
	  
625 626 627 628 629 630 631 632 633 634 635 636 637 638
  let wmk w =  (* incr wuid; w *)  (* hash-consing disabled *)
    try WHash.find wmemo w
    with Not_found -> 
      incr wuid; 
      WHash.add wmemo w w;
(*      Format.fprintf Format.std_formatter "W:%a@." 
	print_witness w; *)
      w

  let wpair p1 p2 = wmk (WPair (p1,p2, wslot()))
  let wxml p1 p2 = wmk (WXml (p1,p2, wslot()))
  let wrecord r o = wmk (WRecord (r,o, wslot()))
  let wfun f = wmk (WFun (f, wslot()))

639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707
  let bool_pair f =
    BoolPair.compute 
      ~empty:false ~full:true 
      ~cup:(||) ~cap:(&&) ~diff:(fun x y -> x && not y) 
      ~atom:f

  let bool_rec f =
    BoolRec.compute 
      ~empty:false ~full:true 
      ~cup:(||) ~cap:(&&) ~diff:(fun x y -> x && not y) 
      ~atom:f

  let rec node_has n = function
    | WXml (_,_,s) | WPair (_,_,s) | WFun (_,s) | WRecord (_,_,s) as w ->
	if NodeSet.mem n s.wnodes_in then true
	else if NodeSet.mem n s.wnodes_out then false
	else (let r = type_has (descr n) w in
	      if r then s.wnodes_in <- NodeSet.add n s.wnodes_in
	      else s.wnodes_out <- NodeSet.add n s.wnodes_out;
	      r)
    | w -> type_has (descr n) w

  and type_has t = function
    | WInt i -> Intervals.contains i t.ints
    | WChar c -> Chars.contains c t.chars
    | WAtom a -> Atoms.contains_sample a t.atoms
    | WPair (w1,w2,_) -> 
	bool_pair 
	  (fun (n1,n2) -> node_has n1 w1 && node_has n2 w2) 
	  t.times
    | WXml (w1,w2,_) ->
	bool_pair 
	  (fun (n1,n2) -> node_has n1 w1 && node_has n2 w2)
	  t.xml
    | WFun (f,_) ->
	bool_pair 
	  (fun (n1,n2) ->
	     List.for_all
	       (fun (x,y) ->
		  not (node_has n1 x) ||
		    (match y with None -> false
		       | Some y -> node_has n2 y))
	       f) 
	  t.arrow
    | WRecord (f,o,_) ->
	bool_rec 
	  (fun (o',f') ->
	     ((not o) || o') && (
	       let checked = ref 0 in
	       try 
		 LabelMap.iteri 
		   (fun l n ->
		      let w = 
			try let w = LabelMap.assoc l f in incr checked; w
			with Not_found -> WAbsent in
		      if not (node_has n w) then raise Exit
		   ) f'; 
		 o' || (LabelMap.length f == !checked)
		   (* All the remaining fields cannot be WAbsent
		      because of an invariant. Otherwise, we must
		      check that all are WAbsent here. *)
	       with Exit -> false))
	  t.record
    | WAbsent -> t.absent
    | WAbstract a -> Abstract.contains_sample a t.abstract
end



708

709 710 711
type slot = { mutable status : status; 
	       mutable notify : notify;
	       mutable active : bool }
712 713
and status = Empty | NEmpty of Witness.witness | Maybe
and notify = Nothing | Do of slot * (Witness.witness -> unit) * notify
714 715

let slot_empty = { status = Empty; active = false; notify = Nothing }
716 717
let slot_nempty w = { status = NEmpty w;
		     active = false; notify = Nothing }
718

719
let rec notify w = function
720 721
  | Nothing -> ()
  | Do (n,f,rem) -> 
722 723
      if n.status == Maybe then (try f w with NotEmpty -> ());
      notify w rem
724 725 726 727 728 729

let rec iter_s s f = function
  | [] -> ()
  | arg::rem -> f arg s; iter_s s f rem


730 731 732
let set s w =
  s.status <- NEmpty w;
  notify w s.notify;
733
  s.notify <- Nothing; 
734 735
  raise NotEmpty

736
let rec big_conj f l n w =
737
  match l with
738 739
    | [] -> set n w
    | [arg] -> f w arg n
740
    | arg::rem ->
741 742
	let s = 
	  { status = Maybe; active = false; 
743
	    notify = Do (n,(big_conj f rem n), Nothing) } in
744
	try 
745
	  f w arg s;
746
	  if s.active then n.active <- true
747
	with NotEmpty when n.status == Empty || n.status == Maybe -> ()
748

749
let memo = DescrHash.create 8191
750 751
let marks = ref [] 

752 753
let count_subtype = Stats.Counter.create "Subtyping internal loop" 

754 755
let complex = ref 0

756
let rec slot d =
757
  incr complex;
758
  Stats.Counter.incr count_subtype; 
759 760 761
  if d.absent then slot_nempty Witness.WAbsent
  else if not (Intervals.is_empty d.ints) 
  then slot_nempty (Witness.WInt (Intervals.sample d.ints))
762
  else if not (Atoms.is_empty d.atoms) 
763
  then slot_nempty (Witness.WAtom (Atoms.sample d.atoms))
764
  else if not (Chars.is_empty d.chars) 
765
  then slot_nempty (Witness.WChar (Chars.sample d.chars))
766
  else if not (Abstract.is_empty d.abstract) 
767
  then slot_nempty (Witness.WAbstract (Abstract.sample d.abstract))
768 769 770 771 772
  else try DescrHash.find memo d
  with Not_found ->
    let s = { status = Maybe; active = false; notify = Nothing } in
    DescrHash.add memo d s;
    (try
773
       iter_s s check_times (BoolPair.get d.times);  
774
       iter_s s check_xml (BoolPair.get d.xml); 
775
       iter_s s check_arrow (BoolPair.get d.arrow);
776 777
       iter_s s check_record (get_record d.record);
       if s.active then marks := s :: !marks else s.status <- Empty;
778
     with NotEmpty -> ());
779 780
    s

781 782 783 784 785
and guard n t f = match (slot t) with
  | { status = Empty } -> ()
  | { status = Maybe } as s -> n.active <- true; s.notify <- Do (n,f,s.notify)
  | { status = NEmpty v } -> f v

786
and check_times (left,right) s =
787 788 789 790 791 792 793 794
  let rec aux w1 w2 accu1 accu2 seen = function
    (* Find a product in right which contains (w1,w2) *)
    | [] -> (* no such product: the current witness is in the difference. *)
	set s (Witness.wpair w1 w2)
    | (n1,n2) :: rest 
	when (Witness.node_has n1 w1) && (Witness.node_has n2 w2) ->
	let right = seen @ rest in
	let accu2' = diff accu2 (descr n2) in 
795 796 797
	guard s accu2' (fun w2 -> aux w1 w2 accu1 accu2' [] right);
	let accu1' = diff accu1 (descr n1) in
	guard s accu1' (fun w1 -> aux w1 w2 accu1' accu2 [] right)
798
    | k :: rest -> aux w1 w2 accu1 accu2 (k::seen) rest
799
  in
800 801
  let (t1,t2) = cap_product any any left in
  guard s t1 (fun w1 -> guard s t2 (fun w2 -> aux w1 w2 t1 t2 [] right))
802 803

and check_xml (left,right) s =
804 805 806 807 808 809 810 811
  let rec aux w1 w2 accu1 accu2 seen = function
    (* Find a product in right which contains (w1,w2) *)
    | [] -> (* no such product: the current witness is in the difference. *)
	set s (Witness.wxml w1 w2)
    | (n1,n2) :: rest 
	when (Witness.node_has n1 w1) && (Witness.node_has n2 w2) ->
	let right = seen @ rest in
	let accu2' = diff accu2 (descr n2) in 
812 813 814
	guard s accu2' (fun w2 -> aux w1 w2 accu1 accu2' [] right);
	let accu1' = diff accu1 (descr n1) in
	guard s accu1' (fun w1 -> aux w1 w2 accu1' accu2 [] right)
815
    | k :: rest -> aux w1 w2 accu1 accu2 (k::seen) rest
816
  in
817 818
  let (t1,t2) = cap_product any any_pair left in
  guard s t1 (fun w1 -> guard s t2 (fun w2 -> aux w1 w2 t1 t2 [] right))
819

820
and check_arrow (left,right) s =
821 822
  let single_right f (s1,s2) s =
    let rec aux w1 w2 accu1 accu2 left = match left with
823
      | (t1,t2)::left ->
824
          let accu1' = diff_t accu1 t1 in 
825
	  guard s accu1' (fun w1 -> aux w1 w2 accu1' accu2 left);
826 827

          let accu2' = cap_t  accu2 t2 in 
828
	  guard s accu2' (fun w2 -> aux w1 (Some w2) accu1 accu2' left)
829 830 831
      | [] -> 
	  let f = match f with Witness.WFun (f,_) -> f | _ -> assert false in
	  set s (Witness.wfun ((w1,w2)::f))
832 833
    in
    let accu1 = descr s1 in
834
    guard s accu1 (fun w1 -> aux w1 None accu1 (neg (descr s2)) left)
835
  in
836
  big_conj single_right right s (Witness.wfun [])
837

838
and check_record (labels,(oleft,left),rights) s =
839 840
  let rec aux ws accus seen = function
    | [] ->
841 842
	let rec aux w i = function
	  | [] -> assert (i == Array.length ws); w
843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862
	  | l::labs -> 
	      let w = match ws.(i) with 
		| Witness.WAbsent -> w
		| wl -> LabelMap.add l wl w in
	      aux w (succ i) labs in
	set s (Witness.wrecord (aux LabelMap.empty 0 labels) oleft)
    | (false,_) :: rest when oleft -> aux ws accus seen rest
    | (_,f) :: rest 
	when not (exists (Array.length left)
		    (fun i -> not (Witness.type_has f.(i) ws.(i)))) ->
	(* TODO: a version f get_record which keeps nodes in neg records. *)
	let right = seen @ rest in
	for i = 0 to Array.length left - 1 do
	  let di = diff accus.(i) f.(i) in
	  guard s di (fun wi -> 
			let accus' = Array.copy accus in accus'.(i) <- di;
			let ws' = Array.copy ws in ws'.(i) <- wi;
			aux ws' accus' [] right);
	done
    | k :: rest -> aux ws accus (k::seen) rest
863
  in
864
  let rec start wl i =
865
    if (i < 0) then aux (Array.of_list wl) left [] rights
866
    else guard s left.(i) (fun w -> start (w::wl) (i - 1))
867
  in
868
  start [] (Array.length left - 1)
869 870


871

872
let timer_subtype = Stats.Timer.create "Types.is_empty"
873

874